# PM45m variable speed mill mods + full 3 axis CNC conversion build log (Pics HEAVY)



## gt40 (Feb 26, 2012)

*PM45m mill CNC conversion build log(Update R8 to BT30 conversion)*

After a month and a half, I am really liking the new PM45m variable speed. FYI, the factory variable speed is pretty decent. It also adjusting between 45 and 3500 rpm, so it seems to be worth it vs buying a vfd etc. 

Previously, I had a mini mill and it ended up being just like when I went from the harbor freight 8x17 lathe to the jet 13x40- No substitute for size

Mods/Addition so far:
Kurt vice
Phase II table + 6" 3 jaw chuck(stock one from the Jet 13x40 lathe I had laying around)
Bison ER40 collet holder
Techniks er40 collet set
Lyndex ball bearing nut
Glacern r8 chuck
diy welded stand
Criterion S2 boring head(ebay)

This weekend, I added DRO I got a great deal on a mitutoyo scale for the quill and added a 2 axis glass scale set= all from fleebay. I made all the brackets out of some extra scrap of mic plate I had laying around that was 3/4" thick. A bit overkill but it is absolutely smooth through the full range. I am really happy getting the x axis scale on the back of the machine. You can hardly tell its there. Here are a few pics:



































Going to just make some lights now for a while with it. Eventually, I hope to cnc it but I am still learning to mill

Mark


----------



## precisionworks (Feb 27, 2012)

*Re: PM45m variable speed mill mods*



> Kurt vice
> Phase II table + 6" 3 jaw chuck(stock one from the Jet 13x40 lathe I had laying around)
> Bison ER40 collet holder
> Techniks er40 collet set
> ...



Great choices on tooling  The better the tooling the less frustration when making parts.

You may want to tear down the rotary table & have a look at the internals. My Phase II super spacer needed a couple of hours of filing, fitting, polishing, etc., before it started to feel like a Yuasa or Hardinge. If you ever find a great buy on an 8" Phase II or Yuasa it's well worth the money to get the larger through hole. My 8" super spacer has already claimed the left side of the table & doesn't leave that location very often. 

Nice job on both the X & Y DRO as well as the Z axis. With the Z readout you'll have total confidence about depth of cut.


----------



## wquiles (Feb 27, 2012)

*Re: PM45m variable speed mill mods*

Great update. Having a DRO makes it a joy to use. I did my own VFD conversion and can also attest to how much more versatile a mill gets when it gets variable drive


----------



## StrikerDown (Feb 28, 2012)

*Re: PM45m variable speed mill mods*

The whole thing SUCKS!


Perhaps I should elaborate... 

It sucks that it's not in my garage! Very nice set up and accessories dude! So badly I want to add X&Y DRO to my RF-31. I have a similar set up on the quill and love it. After the pennies add up to a TIG welder then maybe... Getting close!


----------



## precisionworks (Feb 29, 2012)

*Re: PM45m variable speed mill mods*



> So badly I want to add X&Y DRO to my RF-31.


Without a DRO (on either a mill or lathe) it is possible to do accurate work ... at a very slow pace. The DRO pays for itself quickly in scrap reduction.


----------



## StrikerDown (Feb 29, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> Without a DRO (on either a mill or lathe) it is possible to do accurate work ... at a very slow pace. The DRO pays for itself quickly in scrap reduction.



Yes, even quicker if the scrap is a 1911 frame or slide!


----------



## precisionworks (Feb 29, 2012)

*Re: PM45m variable speed mill mods*



StrikerDown said:


> Yes, even quicker if the scrap is a 1911 frame or slide!


Even a DRO is no guarantee against stupidity. In less than one year I've managed to destroy or mutilate $650 worth of lights, four in total. The details don't really matter but in every case it was either a bad setup or failure to reset zero after a tool change.

This is somewhat interesting ... on the SWM V10R Ti groove mod the roughing is done with a DNMG-433. That's a 55° diamond that does a great job on thin walled titanium parts or whenever vibration can be a problem. The DNMG hogs away 95% of the metal & leaves just a bit for the DCGT-21.50.5 high positive aluminum cutting insert. The high pos works well because the cutting force is tiny but the .008" tip radius is fragile. One tube is guaranteed & it will make it at least part of the way through a second tube before the tip is gone. Finish is nice, around 16 Ra:






When the tip wears or breaks off (which takes exactly one heartbeat) the finish goes to hell. Index to the other point & go back in but stop .005" short - that's how much tip is gone. Go back in to zero & guess what ... the part will be .010" smaller than desired


----------



## gt40 (Mar 19, 2012)

*Re: PM45m variable speed mill mods*

Ordered a 3 axis ac servo kit from DMM tech. http://www.dmm-tech.com/cncsystems_main.html

They are getting decent reviews on cnc zone. Pretty plug in play for the kit with cables etc. AC servos are supposed to be nice. You need to add software and stick the stuff in a control box + pc to run itand ball screws, brackets to mount the servos etc. I ditched thefactory psu and went to an antek 63v 23amp one at their suggestionto pick up rpm on the servos. 

http://www.antekinc.com/pdf/PS-15N44R.pdf

The techs actually seem to know what they are talking about and spent time answering my silly questions. It should at least give me something to do while I wait for parts on my lathe


----------



## precisionworks (Mar 19, 2012)

*Re: PM45m variable speed mill mods*

I already have an old PC Loaded with windows xp. How much do you figure you'll have in your 3 axis conversion?


----------



## gt40 (Mar 19, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> I already have an old PC Loaded with windows xp. How much do you figure you'll have in your 3 axis conversion?




Conversion costs=Roughly 2k on the low side and skys the limit on the high. I am budgeting 2800 to 3k


Fixed costs not counting a rf45 mill breaking down as follows:

$1300 for 950 watt 3 axis dmm tech ac servo kit: http://dmm-tech.com/Files/DMMTechnology_multiaxiscatalogue_Rev.1.1.pdf

$100 to $200 for 1 shot oiler: http://cnccookbook.com/CCMilllOneShot.htm

$450-$600 for 3 ball screws + ball nuts = c7 class (you can also spend 10k per axis on this one) decent site on someone doing a conversion: http://www.graetech.com/index_files/Page1897.htm

$100 for belts, pulleys from spi- si: http://www.sdp-si.com/eStore/CoverPg/Drive_Components.htm + good additional info: http://cnccookbook.com/CCMillCNCServos.html

$50-$100 for material costs for brackets to mount the servos

mach 3= $175 http://www.machsupport.com/purchase.php

$25-$ 100 PC case for servo control box

$100- $200 PC running xp, vista or window 7 http://www.tigerdirect.com/applications/Category/guidedSearch.asp?CatId=6&sel=Price;Price4




a few good threads on rf45 clone builds:

http://www.cnczone.com/forums/benchtop_machines/101638-bolton_zx45_conversion.html

http://www.cnczone.com/forums/benchtop_machines/120917-copycat_rf45_clone.html

http://www.cnczone.com/forums/benchtop_machines/100759-dm45_rf45_build_thread_-.html

http://www.cnczone.com/forums/benchtop_machines/122462-pm-45_cnc_conversion_rf45.html

http://www.cnczone.com/forums/benchtop_machines/121628-precision_matthews_pm-45m_3_axis-4.html

http://www.ocf.berkeley.edu/~davytong/personal_projects_and_hobbies/mill3.htm


On a final note, this video really got me to want to learn more about cnc:


----------



## gt40 (Mar 24, 2012)

*Re: PM45m variable speed mill mods*

I officially started the cnc conversion. Picked up 80lbs of aluminum rem stock from industrial metal supply. Mostly 2 1/2" x 3" thick and 1/2" thick plate. There is also 20lb chunk of steel rem for the z axis ball nut mount. All of the aluminum was at 1.69lb and the steel was 1.39. Basically a $150 for stock metal costs for the conversion:






Got to use the new Glacern Face mill. It really is awesome!





I should have snapped a pic right after I milled it- shiny metal and dead smooth flat. I took this one 3 hours later after measuring the mill a and stock to check fitment and design. This chunk is a a bearing block to be.

Here is a pic with the basic shape cut and one side bored for the double row angular contact bearing. There are to be 2 double row bearings on each block in a sandwich to support each end of the ballscrew.






I plan to mount a block like this on each side of the x axis and then a 1/2" thick plate for the offset to mount the motor.


UPS man should be busy with servos, ballscrews, power supplies etc on the way.

I machined to identical bearing blocks and will use the stock bolt holes for coplanar alignment. Waiting on my ballscrews though to verify alignment before i drill the bearing blocks for mounting holes. Here are some pics to show perspective better:

Width of bearing block:






I basically cut the blocks to size and then drilled through the block with a 1/2" drill to to provide a way to locate and bore the bearing hole on each side of the block and have them be coplanar.






Checking fitment:






gang machining to make them identical:






finished blocks with 2 bearings per side:







More to come, thanks for looking....


----------



## gt40 (Mar 27, 2012)

*Re: PM45m variable speed mill mods*

today everything arrived:

dmm ac servo kit, antec 65v psu, ballscrews, limit switches, ballscrews, ballnuts...





roton:





dmm control board:





removed the table and took measurements for x axis ball nut mount:






table off:


----------



## wquiles (Mar 27, 2012)

*Re: PM45m variable speed mill mods*

Awesome - thanks much for the photos


----------



## precisionworks (Mar 28, 2012)

*Re: PM45m variable speed mill mods*

Does the motor have enough torque to move the table when a 165# (75 kg) indexer is mounted on the far side of the table?


----------



## gt40 (Mar 28, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> Does the motor have enough torque to move the table when a 165# (75 kg) indexer is mounted on the far side of the table?



The 750 watt ac servos are more than double necessary torque to do that. To the point, here is a video showing z axis rapids powered by 300 watt motors which are half the size of my servos in terms of specs. Keep in mind the head is over 200lbs and you are moving vertically:



The tech of the servo company actually laughed when I told him I wanted the 750 watt motors. He said the smaller ones could snap a 1/2" end mill. With smaller sized servos, you can gear them 3 or 4 to one to gain torque but he said most people go 1:1 with these. I am going 2:1 in any case.

Here is another with someone with basically the same mill and the smaller servo setup:





Decent write up on the issues:

http://www.graetech.com/index_files/Page736.htm


----------



## PEU (Mar 29, 2012)

*Re: PM45m variable speed mill mods*

screws: I see you have 2 nuts per screw, do they come with accesories for preoloading them? You did not like ballscrews?

servos: with 2.9nm nominal torque you plan to go 2:1 on these, wow  

z axis: will you use a counterweight for a smooth ride or you will leave the servo to deal with the gravity?


Pablo


----------



## wquiles (Mar 29, 2012)

*Re: PM45m variable speed mill mods*

gt40, I hope you don't mind a slightly off-topic question on this counterweight stuff ...



PEU said:


> z axis: will you use a counterweight for a smooth ride or you will leave the servo to deal with the gravity?


Two questions: 
1) In a knee mill such as mine, where the weight of the table moving up and down the Z axis changes based on what is on the table (duh!), how does one go about a counterweight? Do you assume/planned for an average value? 

2) Where/how does one implement this counter weight on a knee mill?

Will


----------



## gt40 (Mar 29, 2012)

*Re: PM45m variable speed mill mods*



PEU said:


> screws: I see you have 2 nuts per screw, do they come with accesories for preoloading them? You did not like ballscrews?
> 
> servos: with 2.9nm nominal torque you plan to go 2:1 on these, wow
> 
> ...



I got roton ballscrews and ballnuts. I am making the mount for the ballnuts which will preload the nuts with 2 ballnuts per axis. The pic of the acme nut was taken for reference while I figured out where to put the ballnut mount. I plan to use belleville washers to preload 200lbs per nut.


----------



## PEU (Mar 29, 2012)

*Re: PM45m variable speed mill mods*



wquiles said:


> 2) Where/how does one implement this counter weight on a knee mill?



Never saw a knee mill with counterweight, not saying they do not exist. Maybe a solution would be to use a gas spring.


Pablo


----------



## gt40 (Mar 29, 2012)

*Re: PM45m variable speed mill mods*



wquiles said:


> gt40, I hope you don't mind a slightly off-topic question on this counterweight stuff ...
> 
> 
> Two questions:
> ...




Regarding the counterweight issue, I have researched around a dozen rf45 conversions. 


3 options: 

Gas springs

Counterweight

Giant servos


I am opting for the latter. There have been good results all three ways.


----------



## gadget_lover (Mar 29, 2012)

*Re: PM45m variable speed mill mods*



wquiles said:


> gt40, I hope you don't mind a slightly off-topic question on this counterweight stuff ...
> 
> 
> Two questions:
> ...



I don't think it's desirable on the knee mill, especially one as small as ours. Part of the rigidity is the heavy lump of iron resting solidly on the leadscrew. If you counterbalanced it you would then need to lock the knee for all operations, right?

Daniel


----------



## gt40 (Mar 29, 2012)

*Re: PM45m variable speed mill mods*

duh!!! is right. I should have read your question better  I really don't know on knee mills for the z. Maybe a giant servo is all that is needed.

Here is a decent knee mill cnc conversion:

http://plsntcov.8m.com/JetMill/Jet.html

Looks like a lot of the same issues with different mounting of ballscrews and servos...


----------



## wquiles (Mar 30, 2012)

*Re: PM45m variable speed mill mods*



gadget_lover said:


> I don't think it's desirable on the knee mill, especially one as small as ours. Part of the rigidity is the heavy lump of iron resting solidly on the leadscrew. If you counterbalanced it you would then need to lock the knee for all operations, right?



Thanks for the clarification. I should however note that I anyway always lock the knee for "all" operations today - I like as rigid a platform as possible 

I don't have any money for a CNC conversion, but I certainly like the learning part - maybe a future project (if/when I win the lottery!)

Will


----------



## gt40 (Mar 30, 2012)

*Re: PM45m variable speed mill mods*



wquiles said:


> Thanks for the clarification. I should however note that I anyway always lock the knee for "all" operations today - I like as rigid a platform as possible
> 
> I don't have any money for a CNC conversion, but I certainly like the learning part - maybe a future project (if/when I win the lottery!)
> 
> Will



I have been doing the equivalent, locking the z with my mill.

What's cool about the conversion is that putting ballscrews and servo/steppers on the mill is similar to having all three axis locked down at all times if you do a decent job with the build. Ballscrews are so efficient at transmitting motion you can have the cutter pull the piece into the cut. Servo/steppers provide hundreds or thousands of oz/inch force to counter act that. Add in a reduction of backlash by removing acme screws and nuts and everything should be much more rigid. 

As far as costs, if you are using steppers, you could probably do it for under 2k if you are watching costs. 3 axis motor drive kits are under 1k. 

I almost went with a knee mill and looked at both types of machines. I just don't have the room though for a full knee.


----------



## precisionworks (Apr 1, 2012)

*Re: PM45m variable speed mill mods*

You may want to figure the price of a turn-key kit (all the parts you bought + the brackets & bearing housings you made, etc.) I may be interested.


----------



## gt40 (Apr 1, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> You may want to figure the price of a turn-key kit (all the parts you bought + the brackets & bearing housings you made, etc.) I may be interested.



I will let you know upon seeing all this actually works. :nana: 

So far, everything comes down to measuring and I am standing on the shoulders of all the builds on this mill I have been able to read. One thing, you may end up having to drill and tap some holes because these chinese mills have variations according to what I have seen posted.

On another note,

I am pretty happy with my x axis pre loaded double nut and mount. It currently has 2 50lb bellville washers per screw to provide preload force. The idea is 2 opposing ballnuts being pushed apart can reduce or eliminate backlash. 

In this pic, you can see the nut loose and the parts, there are actually 2 opposing bellevilles per bolt like this () They generate 50lbs wer washer x 8 washers:








All tightened up:







Head on view:







It fits!






Next I got to put the lathe back together enough to try and turn the ball screws to size. 

Thanks for looking...


----------



## Maglin (Apr 7, 2012)

*Re: PM45m variable speed mill mods*

Your build is looking good. I think after you add up all the costs of the mill and parts it's close to $7K. That is with an auto drawbar using a fixed table tool changer, building a cabinet, and all the drives and PC stuffs. I have a lot into mine. Now I have to find the time to finish it. I like your X nut. Looks pretty beefy. I'm going with 300# on my preload. I figure the table alone is 100# and with a vise 80# and some large steel work another 100# it just really adds up.

Kept the pictures coming. The worst part is that once it's done you have a lot of learn on the CAM side actually making your tool paths and not breaking cutters.


----------



## gt40 (Apr 15, 2012)

*Re: PM45m variable speed mill mods*



Maglin said:


> Your build is looking good. I think after you add up all the costs of the mill and parts it's close to $7K. That is with an auto drawbar using a fixed table tool changer, building a cabinet, and all the drives and PC stuffs. I have a lot into mine. Now I have to find the time to finish it. I like your X nut. Looks pretty beefy. I'm going with 300# on my preload. I figure the table alone is 100# and with a vise 80# and some large steel work another 100# it just really adds up.
> 
> Kept the pictures coming. The worst part is that once it's done you have a lot of learn on the CAM side actually making your tool paths and not breaking cutters.



I guess it can add up... I am on track so far to keep it under $2500 for the inital conversion. I am going as cheap as I can, repurposing and old pc and cabinet, scrap pipe for the stand etc.


Anyway, just got back from Arizona and got a bit more done. X axis is getting there and fitment seems fine. I turned down the ballscrews- no power feed on the lathe and it was a bit tedious as those things are hard. Remembered reading something on the Roton site and sure enough, they said to anneal the ends with acetylene torch. Once I did that it was fine and I also threaded one end. I drilled and tapped one side for the bearing mount and turned the ballscrew with a drill to check for binding but it all aligned 

Fyi, the preloaded ballnut setup with 2 cheap roton ballnuts (24.00 each + 5/8" ballscrew at $11.00 a foot) seems to have absolutely no backlash with 300lbs of preload from belleville washers. 

Here are few pics:






It fits!






cheap harbor freight marking punch. I am amazed how much i use the set. 






Test fit of the gear side:







Tail side:








BTW, this is my new favorite tool. I always hated tapping and these spiral flute taps are awesome. The chips come through the flutes and they just cut better. I got 4 sizes so far all on ebay:






Close up because I really really like these taps!






That's it for now, thanks for looking.

GT40


----------



## gt40 (May 27, 2012)

*Re: PM45m variable speed mill mods*

Update:

I have made some good progress.

X axis is largely done:






Y axis ball nut block with boss:






I had to take the mill head off. Considering the 300 + lb weight, this was done by disassembly. I will be adding bigger motor anyway:






Gears:






Z axis lower bearing support block. Alignment of Z axis was a little tricky. In the end, i snuck up on it but had to make several of these to get the fitment right. It was hard to take accurate measurements inside the column:






z axis ballnut block. Basically a 3"x8"x5" block with a boss cut on the end. I am really happy with the fitment as there is absolutely no slop:






Here is the opposite view with the boss cap:







3 hp inverter duty motor and drive. It is heavy at 130lbs and makes the AC Tech vfd look tiny:












On another note, I was able to cut grooves in the ways and drill/tap x, y and z axis The grooves will allow for one shot lubrication fed by an oil pump and manifold setup with lines to each side of the the axis + the ball nut mount, 9 in total. I did it using the bridgeport at roadrace engineering. They work on my car and let me use it after hours. First time using one and it cut like butter:




thanks for looking


----------



## PEU (May 28, 2012)

*Re: PM45m variable speed mill mods*

Looking very good!

[edit] 130lbs wow, are you sure the servos can handle that weight plus the head?


Pablo


----------



## gt40 (May 29, 2012)

*Re: PM45m variable speed mill mods*



PEU said:


> Looking very good!
> 
> [edit] 130lbs wow, are you sure the servos can handle that weight plus the head?
> 
> ...



I am gearing them 2:1 for some mechanical advantage + they are 1020 oz servos. The tech at DMM tech where I bought them said they have enough power for direct drive, let alone with gears but we shall see.

On another note, I made a little more progress towards finishing the z axis. I performed surgery on the top of the mill, opening the top up for my flush, undermount bearing block. Not the prettiest cut but it will be covered entirely by the servo mounting plate. I basically climbed up on the mill stand and cut it out with my plasma. I think I won't do that again 






My favorite way for boring the bearing blocks is proving to be a surplus 1" diameter mt3 drill bit. It is the first time working with square and rectangular objects on the lathe. Much faster making the hole and then finishing off with a boring bar:











Thanks for looking...


----------



## gt40 (Jun 8, 2012)

*Re: PM45m variable speed mill mods*

Update:

Well, I have made good progress. x, y and z axis ballnut blocks, angular contact bearing blocks on both ends are also done and x and z servo motor mounting plates are finished. I also was able to test fit the 3 hp inverter duty motor. It is a beast and I think you can't fit a much larger motor without mounting it offset so I am extremely happy. It clears the column with a full 1/2" to spare with it's designated mounting location:






Closeup:






I cut the side plates and hope to mount it tomorrow then make the the 2 step poly v pulleys. That should allow for 2 speed ranges between 100 and 7500 rpm with the vfd. 

Here is a shot of the z axis bearing block and double ball nut with 300lb belleville washers to prevent backlash:






Keep in mind the bearing block is 8" x 4" chunk of aluminum.


Next I have to figure out how to wire the 3 phase motor and the vfd. Anyone in West Los angeles with 3 phase motor experience would be well compensated with wood fired pizza and beer


----------



## precisionworks (Jun 9, 2012)

*Re: PM45m variable speed mill mods*



gt40 said:


> Next I have to figure out how to wire the 3 phase motor and the vfd. Anyone in West Los angeles with 3 phase motor experience would be well compensated with wood fired pizza and beer



GREEN (ground) wire from breaker panel goes to VFD terminal marked PE.

BLACK & WHITE wires from breaker panel go to VFD terminals L1 & L2. Polarity does not matter.

U (T1), V(T2) and W(T3) are phase 1, 2 & 3 and are connected to the motor windings. You also need to run a GREEN (ground) wire from terminal PE to the motor frame (there's a connection point inside the motor wiring box).

Inside the motor wiring box should be 9 leads numbered 1 through 9. There should also be a connection diagram inside that box but if not:

T1 = 1+6+7

T2 = 2+4+8

T3 = 3+5+9


----------



## gadget_lover (Jun 9, 2012)

*Re: PM45m variable speed mill mods*

And then....

You need to find the settings that work for your particular VFD and motor combination.

It's not that hard to do, but the manuals are a hassle to read and understand.

Dan


----------



## wquiles (Jun 9, 2012)

*Re: PM45m variable speed mill mods*



gadget_lover said:


> And then....
> 
> You need to find the settings that work for your particular VFD and motor combination.
> 
> ...



+1

Dan is right on the money. Not "hard", but sometimes confusing 

Don't be afraid to call the customer/technical support number listed in your VDF manual. Those guys should be able to clarify any question you might have regarding settings/wiring/etc..

Will


----------



## PEU (Jun 9, 2012)

*Re: PM45m variable speed mill mods*

Its not that difficult, about a year or so ago I was in the same position, all of the sudden, VFDs started to flow my way in different projects, chinese nonames, deltas, yaskawas, etc. Once you learn the basic setup its just a matter of finding the correct code for the unit/brand. My procedure for a new setup is to reset the unit if its not brand new, and take note of every non default parameter I change, the less you change the better!

Regarding the motor GT40 purchased, I still think is waaay too big/heavy 


Pablo


----------



## precisionworks (Jun 9, 2012)

*Re: PM45m variable speed mill mods*



PEU said:


> Regarding the motor GT40 purchased, I still think is waaay too big/heavy



I've used a number of Baldor M3611 motors for VFD conversions. They weigh 58# (26 Kg) & that's usually all I want to lift into position & bolt into place. They have no shaft encoder & are a good match for a sensorless vector drive.

The Lincoln Electric motor that GT40 has is very nice. One of the best features is the shaft encoder, designated by the Q15L in the model number:






This allows using the motor with a drive that requires a sensor & those drives are sometimes available on eBay for next to nothing ... because motors with a shaft encoder are so expensive. FWIW adding the shaft encoder option to that motor raises the list price by $1561 over the cost of the base motor.


----------



## gt40 (Jun 9, 2012)

*Re: PM45m variable speed mill mods*

FYI, the motor I received was new surplus and still in the orginal Lincoln electric box and packaging. I just put an offer in at $180 + $85.00 shipping, which I got the last one for and they accepted it. I now will have a second one to vfd the jet lathe.

$180 for a vector duty 3 hp like this is sweet. There is still one left: 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290690338337


----------



## PEU (Jun 13, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> I've used a number of Baldor M3611 motors for VFD conversions. They weigh 58# (26 Kg) & that's usually all I want to lift into position & bolt into place. They have no shaft encoder & are a good match for a sensorless vector drive.
> 
> The Lincoln Electric motor that GT40 has is very nice.



130lbs translates to almost 60kg just for the motor, 26kg sounds much more reasonable, still heavy, but reasonable. Keep in mind that this motor is stationary in a head that is NOT stationary.

The servos are 1000 or 3000 rpm? if they are 1000 a 2:1 reduction lowers the speed in half (and doubles torque) and if the ballscrews are 5mm/turn that would translate to a maximum 500x5=1500mm/min or about 60in/min not too fast but fast enough for hobby work 


Pablo


----------



## gt40 (Jun 14, 2012)

*Re: PM45m variable speed mill mods*



PEU said:


> 130lbs translates to almost 60kg just for the motor, 26kg sounds much more reasonable, still heavy, but reasonable. Keep in mind that this motor is stationary in a head that is NOT stationary.
> 
> 
> The servos are 1000 or 3000 rpm? if they are 1000 a 2:1 reduction lowers the speed in half (and doubles torque) and if the ballscrews are 5mm/turn that would translate to a maximum 500x5=1500mm/min or about 60in/min not too fast but fast enough for hobby work
> ...




I share some concerns but keep in mind I lost the weight of the internal gears and shafts in the head. That is probably 10-15 lbs. I should be able to hook up the drive and power it to move the z axis after I finish mounting the motor so we shall see 


Regarding the gearing of the servo pulleys, you are correct: the servo's are geared 2:1 but the numbers for movement I have are different:

Servo: 1300 rpm

Ballscrew: 5 tpi

Geared 1:1= 260 in/min

Geared 2:1= 130 in/min



I will also use air springs if necessary to counter balance the weight.

On a different note, I cut my first poly v pulley. I am using 8 v rib pulleys for the belt drive on the 3 hp motor. The pulleys are 2 step with a 2" and 4" part to allow for 2 speed ranges. These belts run much quieter and smoother + higher grip. After looking at the advantages, I think I will use this type for any future belt drives if possible. The only limitation is you are supposed to have the ribbed pulleys: 

http://www.goodyearep.com/uploadedFiles/Products/Power_Transmission/Banded_Belt/poly-v.pdf

The "v" grooves are .0921" spaced and .07" deep and are 40 degrees not typical of standard lathe cutting tools.

I found a link on practical machinist and Kennametal makes a 40 degree Poly-V insert for their Top Notch holders -- the "NV" insert:






I got some from Carbide Depot, and they work great http://www.carbidedepot.com/detail.aspx?ID=18311

I will post pics of the pulley but I ran out of time last night.


----------



## PEU (Jun 14, 2012)

*Re: PM45m variable speed mill mods*

5mm per turn translates to 5 turns per 25mm, one inch is 25.4mm so our numbers are almost the same.

So, if your motor turns at 1300 rpm but its geared 2:1 the screw sees only 650 rpm, if one turn equals 5mm, then 650 rpm equals 5mm x 650 = 3250mm/min or 127inch/min. My previous numbers were wrong because I computed 5*500 as 1500 instead of 2500  


Pablo


----------



## gt40 (Jun 20, 2012)

*Re: PM45m variable speed mill mods*

I cerakoted all the parts and painted the mill body hammered finish grey. Should match with the sniper grey c cote finish pretty well. I will start assembling everything next. I can't wait. This turned into a bigger project than I thought...


----------



## wquiles (Jun 20, 2012)

*Re: PM45m variable speed mill mods*



gt40 said:


> This turned into a bigger project than I thought...



Happens all the time to me :devil:

But that does not mean I did not enjoy them 

Will


----------



## gt40 (Jun 24, 2012)

*Re: PM45m variable speed mill mods*

Made some real progress today:

Completed the VFD conversion by machining 2 identical 8 rib poly v pulleys exactly .0921 distance between 40 degree .072 deep v grooves and mounted the motor:







I am ready to hook up the vfd but am un sure on the wiring for the motor. I found the wiring diagram but am a newbie on these 3 phase motors . Based on this, is the suggestion below right?









precisionworks said:


> GREEN (ground) wire from breaker panel goes to VFD terminal marked PE.
> 
> BLACK & WHITE wires from breaker panel go to VFD terminals L1 & L2. Polarity does not matter.
> 
> ...



Finally, I hooked up the z axis servo and was able to test it with the heavy motor on it. I only got to run it at less than 50% speed as I was scared I would have a crash otherwise:


----------



## precisionworks (Jun 24, 2012)

*Re: PM45m variable speed mill mods*

Use the "low voltage" wiring diagram.


----------



## gt40 (Jun 25, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> Use the "low voltage" wiring diagram.



*
I am sorry but I am scared to mess the motor wiring up. Is this correct?*

connect t4,t5 and t6 for "configuration" 

Connect U off the vfd to t1 and t7
Connect V off the vfd to t2 and t8
Connect W off the vfd to t3 and t9

I just want to be sure


----------



## PEU (Jun 25, 2012)

*Re: PM45m variable speed mill mods*

cool it moves! 

Does the head have a gas spring to prevent falling when the servos are not powered? 
Have you measured backslash at the Z? to do it properly, adjust a comparator below the head, command a 1/2 inch move down and then one inch up, the difference is your backslash.


Pablo


----------



## gt40 (Jun 26, 2012)

*Re: PM45m variable speed mill mods*

Update:

Today was a good day. I got the AC Tech drive wired without frying everything and the belt drive works!

Thanks to Precisionworks post above... I never worked with one of these till now and it was really not so bad. I am definitely converting the lathe to vfd also after seeing the results.






Video:


----------



## wquiles (Jun 26, 2012)

*Re: PM45m variable speed mill mods*



gt40 said:


> Thanks to Precisionworks post above... I never worked with one of these till now and it was really not so bad. I am definitely converting the lathe to vfd also after seeing the results.


I love my two AC Tech VFD's (one in my Quincy compressor, the other in my knee mill). I am "still" hoping to buy a third to convert my lathe as well. One of these days ...

Will


----------



## gt40 (Jul 15, 2012)

*Re: PM45m variable speed mill mods*

Update:

I got back from Milwaukee and got started on the control box. I was going to go with a separate box but ended up re-purposing the stock electronic box instead. Everything fits together except for the pc. 

I also re-purposed the stock master switch after seeing it was rated for 30 amps. I also mounted an e-stop switch on the side. I will add another on the front later.

Power and e-stop:







Here is the control box. It has the 3 drives, breakout board and antek power supply. I was able to set up the power switch so I have one 240v going into the box. The power switch controls everything so turning it on sends power to the vfd and spindle via relay and also to the 21 amp power supply:






I cut all the wires to length and soldered/shrink wrapped and anchored things. 

Thanks for looking.

Mark


----------



## wquiles (Jul 15, 2012)

*Re: PM45m variable speed mill mods*

Looking good Mark 

Will


----------



## gt40 (Jul 29, 2012)

*Re: PM45m variable speed mill mods*

Update:

I got the machine working with Mach 3 and Z axis is now functional. I feel like I am drinking from a fire hose but at least I got it to working with Mach3. E-stop, limit switches work and the DMM servos are moving the heavy motor and head with authority:


----------



## PEU (Jul 30, 2012)

*Re: PM45m variable speed mill mods*

Congrats! it moves!!


Pablo


----------



## gt40 (Aug 18, 2012)

*Re: PM45m variable speed mill mods*

*Update: first chips video!* 

I finally got spindle speed control. Limit switches work, and things are moving pretty smooth. I still need to properly calibrate things this week end and connect the 1 shot oiler. 

Here is a video using the mach3 circular hole wizard to drill 9 holes:



https://vimeo.com/47754045

Finished:


----------



## wquiles (Aug 19, 2012)

*Re: PM45m variable speed mill mods*

Nice!

Is that an Exair blow gun?

Will


----------



## gt40 (Aug 19, 2012)

*Re: PM45m variable speed mill mods*



wquiles said:


> Nice!
> 
> Is that an Exair blow gun?
> 
> Will



Will, it is a generic from Osh. I am not familiar with Exair...


----------



## gadget_lover (Aug 19, 2012)

*Re: PM45m variable speed mill mods*

That is really impressive. Nice work!

I'm curious about the trade-off of the CNC vs Manual for work that is not repetitive (i.e. not production line) such as adding a bolt circle to an existing part. is it as quick to set it up in Mach3 as it is to use a DRO?

I can do that 9 hole bolt circle in less than 5 minutes on my mill, thanks to the DRO's built in functions. How long did it take you to set it up and run the program?

Daniel


----------



## gt40 (Aug 19, 2012)

*Re: PM45m variable speed mill mods*



gadget_lover said:


> That is really impressive. Nice work!
> 
> I'm curious about the trade-off of the CNC vs Manual for work that is not repetitive (i.e. not production line) such as adding a bolt circle to an existing part. is it as quick to set it up in Mach3 as it is to use a DRO?
> 
> ...



Mach 3 has a built in DRO/ Jog function with "go to capabilities. You can also add a pendant which is basically a hand held controller to do this while you look at the mill instead of the computer screen if you want. So basically, I have a 3 axis power feed mill with jog capabiility to 10th via Mach 3. Since as I am still learning how program it, this is actually really cool because I can move the table faster and better than I could before and cutting/ drilling is smoother than manual. The go to and zero functions are pretty neat as you can tell it to move all 3 axis to a given point.

Repeatability seems to be pretty good too. Below is a video where I zeroed the dro in Mach 3, zeroed the indicator and then moved the table and then hit move to zero button on mach 3:


https://vimeo.com/47833358


----------



## gt40 (Aug 21, 2012)

*Re: PM45m variable speed mill mods*

I moved to actual cutting. Here is a video of first cuts in aluminum, machining a 1.5"x.45" deep pocket in 6061:



https://vimeo.com/47979264


----------



## wquiles (Aug 22, 2012)

*Re: PM45m variable speed mill mods*



gt40 said:


> Will, it is a generic from Osh. I am not familiar with Exair...



At least the plastic handle part looks to be the same basic piece used in my Precision Safety Air gun. You can see more about them, with photos, videos, etc., on my web site:
http://www.atdms.com/exair_stuff.html

Will


----------



## gt40 (Aug 22, 2012)

*Re: PM45m variable speed mill mods*



precisionworks said:


> I've used a number of Baldor M3611 motors for VFD conversions. They weigh 58# (26 Kg) & that's usually all I want to lift into position & bolt into place. They have no shaft encoder & are a good match for a sensorless vector drive.
> 
> The Lincoln Electric motor that GT40 has is very nice. One of the best features is the shaft encoder, designated by the Q15L in the model number:
> 
> ...




Now that I got things working on the motor, I am rethinking this. Are you saying I could get a drive for this motor and then use it as true servo? That would be really cool because I could do rigid tapping then. Any information would be appreciated.


----------



## gt40 (Aug 23, 2012)

*Re: PM45m variable speed mill mods*



wquiles said:


> At least the plastic handle part looks to be the same basic piece used in my Precision Safety Air gun. You can see more about them, with photos, videos, etc., on my web site:
> http://www.atdms.com/exair_stuff.html
> 
> Will



You are as bad as Barry 

I ordered one direct from the company. It was cheaper there than 2 other vendors I found it at. One Exair 1409ss on the way...


----------



## precisionworks (Aug 23, 2012)

*Re: PM45m variable speed mill mods*



gt40 said:


> Are you saying I could get a drive for this motor and then use it as true servo? That would be really cool because I could do rigid tapping then. Any information would be appreciated.


Yep 

Cannot say without looking up your specific motor & encoders vary - but some encoders divide each degree into 3600 parts, some into 36000. They allow precise positioning. But you'll need a closed loop vector drive.


----------



## sanddan52 (Aug 23, 2012)

What size ER collet are you using?

Also, in the last video of the pocket milling what spindle speed were you using.

Great job on the CNC conversion!


----------



## gt40 (Aug 23, 2012)

sanddan52 said:


> What size ER collet are you using?
> 
> Also, in the last video of the pocket milling what spindle speed were you using.
> 
> Great job on the CNC conversion!



Bison ER40 collet holder

I may convert to iso30 spindle. They have one for these mills


----------



## gt40 (Aug 27, 2012)

Update:

I installed my DRO back on the machine and recalibrated things. MUCH better. I still have to play with backlash compensation but the mill is finally starting to cut half way decent. I licensed Mach3 and they have these wizards for most common machining operations that are really awesome. Enter the basic info, zero and hit cycle start. The wizard suite called "new fangled wizard" is really good. You tell it what type of material you are cutting, it calculates speeds and feeds and everything.

Here is a video cutting a 2.5" circle through 1/2" thick 6061:

https://vimeo.com/48270746



Finished:






Measured:






Not perfect but getting there. I measured 2.4845" at smallest and 2.5030" at widest point without use of backlash compensation.

At least the hole is roughly 2.5" and not a full oval any more. Calibrating the steps over the full length of travel made a huge difference. 


Any suggestions would be appreciated.

Thanks for looking


----------



## PEU (Aug 27, 2012)

gt40 said:


> Not perfect but getting there. I measured 2.4845" at smallest and 2.5030" at widest point without use of backlash compensation.



That's about 0.5mm mechanical backslash, too much at least to my standards  
Did you checked all adjusting screws in the ballscrew/nut/supports? if this is the best the ballscrews can do I suggest changing for better ones if you need more accuracy. Using software compensation is a compromise solution, at every reversal of any axis all of them have to stop, compensate with a quick move and then continue trajectory, this leaves marks on the job.


Pablo


----------



## gt40 (Aug 31, 2012)

Update:

I ran the belt driven spindle and measured 7680 rpm with a laser tach. Shortly there after the stock bearings started to smoke from the speed. New angular contact bearings coming tomorrrow. I can verify the following sizes for my PM45M mill that I measured and ordered:
Lower bearing: Kit10853
7207CYP4 Nachi Angular Contact Bearing 35x72x17 Abec-7 
Upper bearing: Kit10852
7206CYP4 Nachi Angular Contact Bearing 30x62x16 Abec-7 

In addition for the belt drive bearing tube that is per GD Marsh's design(http://www.cnccookbook.com/CCMillBeltDrive.html)

I ordered:
(2) Kit8891
7007B Angular Contact Bearing 35x62x14 Ball Bearings

FYI, make sure you install the bearings correctly facing the correct direction. I managed to do both wrong killed a set of cheap angular contact bearings from vxb by installing them with the cage plate facing out which is backwards + tapping them in with a dead blow hammer. 

Don't beat on bearings. In hindsight, this was completely obvious  Handle with care and use a press etc and properly support them by putting the load on the outside only and not the floating assembly in the center.

Good video of the process from Hoss:
http://www.youtube.com/watch?v=hP-XvbV7Pc4

After killing the cheaper 50 dollar abec3 bearings, I ended up buying the fancy abec7 bearings. 250 bucks is a lot of money but they are rated to 18000 rpm vs most of the cheaper bearings are rated at 7500 rpm range. I figured better to have a nice margin and I want the machine to run as quiet and smooth and cool as possible.

On another note, I found that I had failed to properly tighten my y axis center bearing block and that is why my test hole above was less than ideal. With the DRO installed, total backlash is now measuring 0.0000 to 0.0002 when going full range on movement on each axis.


----------



## PEU (Sep 1, 2012)

gt40 said:


> On another note, I found that I had failed to properly tighten my y axis center bearing block and that is why my test hole above was less than ideal. With the DRO installed, total backlash is now measuring 0.0000 to 0.0002 when going full range on movement on each axis.



Very glad to read this, adjustments are a ***** sometimes 


Pablo


----------



## wquiles (Sep 1, 2012)

Nice progress update :twothumbs

Will


----------



## gt40 (Sep 6, 2012)

Update:

Finally able to make something in 3 dimensions. I drew a 5 sided pyramid in ViaCad Pro and actually got it to come out as a part. Learning this side of things is proving more challenging than converting the mill to cnc as well as finding useable cost effective CAD/CAM solutions. 








I am learning Viacad pro 7 as it is fairly robust 3d for $250 and not $2500 like a solidworks. Definitely demo before spending any money. I currently demoing Mesh Cam and Cam Bam and got both to make useable stuff. Mesh Cam does real 3d and I actually got it to make th part above without reading any manuals etc. 

If it is any help to anyone wanting to understand steps to making a part via cnc, here is my workflow using "cheap" options as a cnc "newbie":

1. ViaCad Pro 7 for cad design
2. Export as STL
3. Open with Meshcam 
4. Setup machining parimeters and generate tool paths
5. Export gcode
6. Open gcode in Mach3 and zero
7. Cycle start


----------



## wquiles (Sep 7, 2012)

That was pretty cool!


----------



## gt40 (Oct 14, 2012)

Update:
I added an ethernet smooth stepper to the DMM Tech servos and it worked just fine. I was getting an occasional weird signal and the idea of a dedicated motion control board seems like the right thing. 
I also started work on my flood enclosure. First I had to make a bending brake. The bending brake is basically 3 6ft 1/4" angle iron pieces, some black pipe and 2 3/8 thick pieces for the arms. Plans I got from here:
www.ch601.org/tools/bendbrake/brakeplans.pdf
Pics:








I could bend 1/8" thick aluminum just fine:




This was the first time I ever bent sheet metal but the brake works great:




I can't wait to finish the flood enclosure so I can take the Mill apart and put it on the new stand with everything in a permanent setup. Then i can finally make some lights again


----------



## darkzero (Dec 8, 2012)

Visited Mark today & he was showing me his setup which is very cool. First time I ever got to see a CNC conversion in person & I now know the reason for the addiction. I felt like giggling like a little kid as he was showing me all the cool features he had. Man has he been busy! Can't wait to see more & of your new project! Thanks!


----------



## gt40 (Dec 10, 2012)

Update:

Got things finally coming together:

Flood enclosure base is done and the mill re-assembled. I added an IMachIII M1 pendant from Vista CNC and also calibrated the axis with my dro. 

The big news is I have achieved my accuracy goals using the Roton ballscrews and double nuts= .0001" and .0002 backlash total. Considering the ballscrews so inexpensive, this is pretty cost effective. Everything is working pretty well and I am hooking flood coolant and building the top of the flood enclosure next.

Video:

Full rez link:
https://vimeo.com/55327857



Thanks for looking


----------



## gt40 (Dec 17, 2012)

Update:

I received my 30 taper spindle from Industrial Hobbies. FYI, 100 bucks and they fit the pm45 as well as the ih and zx45 clones of the rf45. Installation was straightforward and it is a drop in. Press the bearing on and reinstall. I decided to go with 30 taper because of cheap bt30 er20, er32 and er40 collet chucks for 25 bucks and the ability to add an automatic tool changer at some point. The 30 taper is beefier and you gain almost 2" on z axis compared to using an er collet chuck. I also picked up a full 1/32" increment set of er20 collets (15 in all) + a set of er32 collets that are all techniks.

Pic of the two spindles. The one on the top is the new 30 taper spindle. I had just pressed one of the bearings on:






Business end comparison:





Sorry about the pics, I snapped with the phone...


----------



## gt40 (Jan 24, 2013)

Update:
I have made some progress with the BT30 spindle clamp conversion. The mill came with r8 taper and I am converting it to BT30 taper. No one makes a BT30 spindle for these machines but I found a cheap source for NBTB 30 taper, which is a manual drawbar design vs the power drawbar design of the BT30 which uses a pull stud and spindle clamp. Looking at the difference between bt30 and NMBT, the only difference seems to be the straight section on the nmbt version where the pull stud would go in on the bt30:

NMTB 30:




BT30:









I took the Industrial Hobbies sourced NMTB 30 spindle and bored the straight section deeper by an inch while keeping the diameter to 0.72". This allows me to fit a ball type gripper where the straight section would be. Next I cut groove a 0.25" wide and a depth of 0.95". When the grippers balls are aligned with the groove, the larger diameter allows the pull stud to be released. I made an aluminum version of the spindle and it released properly. The trick is measuring everything right. 
I will post some more detail later but here are some pics of the new drawbar. It is O1 steel, properly hardened and tempered to around 55 rc. (PID kiln)
Gripper Close up:




Gripper on drawbar with bt30 toolholder:




Gripper parts:




Drawbar (need to cut to final dimensons):





There is no room for springs inside the IH nmtb spindle, I am putting the spring on the top of the pulley with a top hat and fabco 2 stage 4" cylinder. I am shooting for 2500 lbs spindle clamping force. 

FYI, I was inspired by this thread:
BT30 spindle from scratch - with power drawbar and ATC of course


Given the really tight space constraints, my solution has been to use the spindle itself as the "sleeve" for the balls and put the spring on top as I have seen on other power drawbar conversions for RF45 type mills. 

I looked at going the TTS style power drawbar but the 30 taper seems to have advantages with a larger taper, drive dogs for zero slip and abundant cheap bt30 tooling. It is also a natural if i ever get around to building an automatic tool changer. I really am excited that this might actually work!

Thanks for looking,
Gt40


----------



## wquiles (Jan 27, 2013)

That looks very neat. Let us know how it works out


----------



## gt40 (Mar 8, 2013)

Update: 

I took the plunge literally and cut the inside of the spindle to make way for the pull stud gripper. This entailed slightly boring past where the taper terminates and then cutting an internal groove for the balls in the gripper to drop into. I test fit and with the balls in place, tool holders are held and then if you allow the drawbar to move down approximately 1/2", the tool is released. Really just relieved to have things align. Next step was to thread the top of the drawbar and mount the 2 stage cylinder. I also had to remake the motor mount and side plates to move the motor back after extending the head. After cutting the spindle(really scary!) The hardest part is cutting a back chamfer in the internal groove inside.

I spent some time further test fitting the spindle. I found I was .0006" too narrow when the gripper was retracted with all 4 balls in. During my initial test fitting, I only put 2 balls in. With all 4 in and the gripper assembly retracted, the tool holder wouldn't retract all the way into the spindle. As a result, I had to slightly enlarge the bore in the spindle. After that, the gripper works smoothly.

Here are a few pics:

Inside the spindle:






Tail end with belville springs:






Here is a quick sketch of the spindle in powerpoint. To convert the mill to a power draw bar in bt30, I need to machine the part in the oval, make a gripper and draw bar for the new spindle.





I wanted to see if it holds under load so I started on the plate for the 2 stage air cylinder and took some cuts with the new gripper installed. I put a bt30 face mill in, fully inserted it using the gripper with the balls and then manually tightened the bolt on top of belville washers with a wrench. Kind of like manually simulating the forces with the air cylinder activated and push down on the drawbar and then releasing. There were no problems taking 0.15" cut with a glacern 4" face mill at 7500 rpm- it is holding just fine.

Hope to get the power draw bar functional this weekend.

Thanks for looking

Mark


----------



## gadget_lover (Mar 8, 2013)

Did I read that right? 4 inch face mill at 7,500 RPM? I recall that on mild steel I'd run about 750 rpm with a 4 inch face mill. 

What's the magic? The insert, the material or the mill? 

Daniel


----------



## darkzero (Mar 8, 2013)

gadget_lover said:


> Did I read that right? 4 inch face mill at 7,500 RPM? I recall that on mild steel I'd run about 750 rpm with a 4 inch face mill.
> 
> What's the magic? The insert, the material or the mill?
> 
> Daniel



Damn that's crazy for a benchtop & sounds extreme but It's probably cause of his motor, belt drive, 30 spindle, & bearings?


----------



## gt40 (Mar 8, 2013)

I have a 3600 rpm 3 hp extreme duty motor. converting it to belt drive and abec7 bearings with a 2.25 ratio on the pulleys gets me to over 8k. You should see how beautiful it cuts at higher rpm.

here is an example of of a similarly converted cnc mill cutting at 6000 rpm and .5 doc at 90 ipm:

http://www.youtube.com/watch?v=jDWfH4rCXhc


----------



## rmteo (Mar 8, 2013)

The end mill in that video is nowhere near 4in. in diameter - more like 1/2in. Running a 4in. face mill (even on my 10,000+lb. VF-4 VMC) is somewhat scary to say the least.


----------



## precisionworks (Mar 8, 2013)

> Did I read that right? 4 inch face mill at 7,500 RPM?


7500 sfpm isn't on any chart I've seen but it can certainly be done. The important number is the MRR (material removal rate) which may be higher at fewer rpm.



> 3600 rpm 3 hp extreme duty motor. converting it to belt drive and abec7 bearings with a 2.25 ratio on the pulleys gets me to over 8k.


Have you checked the max factory speed on those bearings? IIRC most are 4k to 5k. Above that & it's not common to see grease lube but rather air-oil mist or something similar.


----------



## gt40 (Mar 8, 2013)

i put in these bearings from vxd
Lower bearing: Kit10853
7207CYP4 Nachi Angular Contact Bearing 35x72x17 Abec-7 

7207CYP4 Nachi high precision Angular Ball Bearing with 15 degrees contact angle and Polyamide resin cage, bearing is ABEC-7 (P4) quality and made in Japan, inner diameter is 35mm, outer diameter is 72mm and width is 17mm. 

Item: 7207CYP4 Nachi Ball Bearing
Type: Nachi Angular Ball Bearing
Cage: Polyamide resin cage
Quality: ABEC-7 (P4 quality)
Dimensions: 35mm x 72mm x 17mm/Metric
ID (inner diameter)/Bore: 35mm
OD (outer diameter): 72mm
Width/Height/thickness: 17mm
Size: 35 x 72 x 17 mm
Quantity: One Bearing
Dynamic load rating Cr: 30,500 N
Static load rating Cor: 20,100 N
Limiting Speed:
Grease Lubrication: 15,000 RPM 
Oil Lubrication: 21,000 RPM 


Upper bearing: Kit10852
7206CYP4 Nachi Angular Contact Bearing 30x62x16 Abec-7

7206CYP4 Nachi high precision Angular Ball Bearing with 15 degrees contact angle and Polyamide resin cage, bearing is ABEC-7 (P4) quality and made in Japan, inner diameter is 30mm, outer diameter is 62mm and width is 16mm.
Item: 7206CYP4 Nachi Ball Bearing
Type: Nachi Angular Ball Bearing
Cage: Polyamide resin cage
Quality: ABEC-7 (P4 quality)
Dimensions: 30mm x 62mm x 16mm/Metric
ID (inner diameter)/Bore: 30mm
OD (outer diameter): 62mm
Width/Height/thickness: 16mm
Size: 30 x 62 x 16 mm
Quantity: One Bearing
Limiting Speed:
Grease Lubrication: 18,000 RPM
Oil Lubrication: 24,000 RPM



These are nachi bearings i paid 350 for and broke them in by running them at 8k for 36 hours. Max temp was 85 degrees

Anyway, I will post some video of the face mill after I get the drawbar finished.


----------



## precisionworks (Mar 9, 2013)

That's impressive for top speed, my Class V boat trailer bearings are rated lower 

In addition to bearing speed limitations the MRR is also affected by chatter, tool imbalance, etc. The Boeing article below mentions one point worth noting - _small tools do better in small spindles. _

http://www.mfg-labs.com/filedownloa...igh_Speed_Aluminum_Machining_Presentation.pdf


----------



## gt40 (Mar 9, 2013)

precisionworks said:


> That's impressive for top speed, my Class V boat trailer bearings are rated lower
> 
> In addition to bearing speed limitations the MRR is also affected by chatter, tool imbalance, etc. The Boeing article below mentions one point worth noting - _small tools do better in small spindles. _
> 
> http://www.mfg-labs.com/filedownloa...igh_Speed_Aluminum_Machining_Presentation.pdf



That is a great presentation. I have seen chatter to some extent when machining at higher speeds with regular end mills . The biggest issue has been BUE. Just completed a diy fogbuster mister and it is really making a difference on that. 

On a different note, I just got the face mill and ran it at that speed to test if the new ball gripper would retain the tool under extreme conditions. It was scary but I was standing away from the mill and with an enclosure between me and the tool. It was not a recommendation to use the face mill at that speed.


----------



## precisionworks (Mar 9, 2013)

> It was scary but I was standing away from the mill and with an enclosure between me and the tool. It was not a recommendation to use the face mill at that speed.



As my tower climbing friends always say ... if you die we split your gear :laughing:


----------



## gt40 (Mar 11, 2013)

Update:

My power drawbar conversion to bt30 is functional. I need to clean everything up but it is the first conversion to a bt30 spindle i am aware of. Short video of the mill in its current configuration with the enclosure and the power drawbar during initial testing:

https://vimeo.com/61591516


----------



## unterhausen (Mar 13, 2013)

I have been avoiding this thread, but now I want one of those 30 taper spindles. I have every tool I need in NMTB tooling for my bport. How hard is it to get one of the spindles from Industrial Hobbies?


----------



## gt40 (Mar 14, 2013)

unterhausen said:


> I have been avoiding this thread, but now I want one of those 30 taper spindles. I have every tool I need in NMTB tooling for my bport. How hard is it to get one of the spindles from Industrial Hobbies?



I just called the number on the website and spoke to Tommy to order. It was a hundred bucks I believe.


----------



## Davo J (Mar 27, 2013)

I have been following your progress and also followed the progress of the other thread over on CNC zone, nice work.
Is there anything to stop the balls coming out if the cylinder was to loose pressure with no tooling in there?

Dave


----------



## gt40 (Mar 27, 2013)

Davo J said:


> I have been following your progress and also followed the progress of the other thread over on CNC zone, nice work.
> Is there anything to stop the balls coming out if the cylinder was to loose pressure with no tooling in there?
> 
> Dave



The 4 holes have to be machined with a little care. I used a 15/64" (0.2343") drill first and then enlarged the top of the hole with a 17/64" (0.2656") drill that is not drilled completely through. The smaller hole prevents the ball from going into the center when there is no tool in place and the ball is captive in the recess. 

FYI, I made a new x axis servo bracket with cnc and the combo of cad design, cnc mill with power drawbar was really driven home:

It took 15 minutes to draw the part in viacad(I am still very much learning the basics too), 5 minutes to make an nc g code file using meshcam that incorporated both milling and drilling. I cut out the servo relief, slots and ovals with a 5/16" end mill and then drilled 7/32" holes to be tapped for mounting the servo drive. Actual machining was less than 6 minutes including a tool change. I am now learning about offsets in Mach3 and it is really cool. You set up offsets so you don't have to set zero every time you change a tool. With the power drawbar and bt30 tool holders, you zero your stock at the start with the mach 3 tool electronic probe I built, load the g code and hit cycle start. Then the machining commences until you need a tool change and the mill stops automatically. Hit the pneumatic switch and the tool drops out and put the other one in without re- zeroing. Hit cycle start again for the drill cycle. This is so much faster than getting out wrenches, loosening the r8 draw bar, tapping it and then replacing it with another collet and tightening. After all that, I still had to reset zero before. Now it takes more time to write this. Drilling took less than 2 minutes to peck drill 4 holes through the 5/8" thick aluminum, all perfectly aligned in relation to the relief cut for the servo drive. 

I am doing the same for y axis and z axis. The new cnc parts are just perfect + I have been able to extend my travels on the axis significantly and the new servo plates allow me to gain even more travel from lessons learned. As an example, I am at 12.5" travel now on the y axis with the head extension and new servo mounting plate. Stock was 8". Having almost 13" in y travel is awesome 

Hope that helps.


----------



## Davo J (Mar 27, 2013)

gt40 said:


> The 4 holes have to be machined with a little care. I used a 15/64" (0.2343") drill first and then enlarged the top of the hole with a 17/64" (0.2656") drill that is not drilled completely through. The smaller hole prevents the ball from going into the center when there is no tool in place and the ball is captive in the recess.
> 
> FYI, I made a new x axis servo bracket with cnc and the combo of cad design, cnc mill with power drawbar was really driven home:
> 
> ...



Thanks for that, I have had a H/V manual machine for 7 years (like Chich's on CNC zone) it's sold as the Grizzly 3617 over there or used to be. I will be converting it soon as I have the ball screws. I am thinking of just making weldments to get it going then CNC out new mounts for the servos etc as they will be a good learning curve and be a lot quicker to make.

My machine has the NT30 spindle in it and I have been toying with the idea after seeing that thread on CNC zone, and then seeing this thread has given me inspiration to go ahead. I have 25 or so tool holders that are NT30 I would have to sell off and change over to the BT30 instead, but that is not a big hassle.

I see your getting the CNC programing etc times down, keep up the great work I am watching with interest and have been since the beginning of the thread.

Dave


----------



## gt40 (Mar 27, 2013)

If you already have a 30 taper that is sweet. I would get it cnc so you can make the real mounts brackets and then go from there. good luck and be sure to post. Still learning as I go myself...


----------



## gt40 (Apr 1, 2013)

Update:

I cleaned up everything with the enclosure and things are starting to come together. A few pics of the mill in it's current state with a power drawbar, one shot oiler, enclosure and diy fog buster with pressurized coolant:

Shot of the mill head with the bt30 power drawbar installed:







Belleville springs:







Overview shot showing the enclosure. You can also kind of see the 3.5" head extension. *I am getting a full 12.75" of Y travel now.* I will need to make a fixture plate to take full advantage. Considering these mills only have 8" Y travel, this is really awesome:






Power drawbar switch. I ended up using a foot pedal momentary pneumatic switch. Seems more robust than the toggle type and the price is right:






Diy fog buster built out of scrap 1/8" npt plumbing parts I had around and a mig nozzle tip. I forgot to snap a pic of the pressurized coolant tank but it is a whole house water filter housing modified with a pick up tube. compressed air goes in and forces the coolant out through the pick up tube connected to the top. The needle valves allow for both pressure and fluid level adjustments. Works really well:


----------

