# Machine Shop Class Projects..... (My New Lathes.....)



## darkzero

Well on Saturdays anyway. :nana: :laughing:












That's my little brother on the Rockford.

I've only used the Le Blonds & Rockford so far. There's also a couple of Logans, a Hardinge, & a couple others I don't recall the names/aren't familiar with. There's also a bunch of Bridgeports that I get to play with later. 

Gives a new perspective to my mini lathe now!


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## wquiles

*Re: My New Lathes.....*

Cool - is it a class/course you are taking?

Will


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## KC2IXE

*Re: My New Lathes.....*

first time you dial in, say a .125 cut on some 12L14 or something, and watch the lathe grunt slightly, and peal off the cut like it was nothing, THAT is when you really get perspective on the difference between say the LeBlond and a Mini-lathe.

There is one huge problem - you get used to being able to reduce a part .250 diameter at a time, and you go back to the mini-lathe, and you go nuts "Gahhh - I have to take 3-5 passes"


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## wquiles

*Re: My New Lathes.....*

That is exactly the problem I have today - I don't know how could I ever go back to a small lathe, and I only have a 12x lathe, nothing as big/sturdy as the lathes in his picture above!


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## darkzero

*Re: My New Lathes.....*



wquiles said:


> Cool - is it a class/course you are taking?
> 
> Will


 
Yes. My little brother needed a techinical credit for high school so he choose to take this class at the local CC. I decided to join him, plus I'm his ride. 




KC2IXE said:


> first time you dial in, say a .125 cut on some 12L14 or something, and watch the lathe grunt slightly, and peal off the cut like it was nothing, THAT is when you really get perspective on the difference between say the LeBlond and a Mini-lathe.
> 
> There is one huge problem - you get used to being able to reduce a part .250 diameter at a time, and you go back to the mini-lathe, and you go nuts "Gahhh - I have to take 3-5 passes"


 
Tell me about. I pushed to see how deep of a cut it could take. I can believe how big the chips were when I was making roughing cuts on my hammer handle as I'm not used to seeing chips that big.


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## Rothrandir

*Re: My New Lathes.....*

Please post pictures of the things you make in class!


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## KC2IXE

*Re: My New Lathes.....*

I only have a little Atlas 12" - I know I'm really working the lathe when I hear it slow down when the cut engages. Rare I have to take that much of a cut, but there are times

I really do want a better lathe, but...


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## darkzero

*Re: My New Lathes.....*



Rothrandir said:


> Please post pictures of the things you make in class!


 
Will do. Our first project is a ball peen hammer, aluminum handle with a brass head that threads onto the handle. It's pretty cool, I've got the prints if anyone is interested in making one.




KC2IXE said:


> I only have a little Atlas 12" - I know I'm really working the lathe when I hear it slow down when the cut engages. Rare I have to take that much of a cut, but there are times
> 
> I really do want a better lathe, but...


 
I took some 0.010< passes @ 1200 rpms the other day on my mini lathe & I could hear my motor struggle a bit. What a baby! :laughing: :candle:


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## darkzero

*Re: My New Lathes.....*



Rothrandir said:


> Please post pictures of the things you make in class!


 
The handle for my hammer which teaches that basics. Knurling is not all that great, used a really old Armstrong knurler but it's very coarse which is perfect for a grippy handle. Need to finish the brass head which is done on a 5C collect & a mill. The handle was turned between centers.


















I see why the hammer is perfect for thefirs project. It really teaches a lot about basic operations. One thing I learned making this was turning a long taper which I have never done before (well I'm not capable of doing so with my 8x14). Also got very comfortable at threading now. Before turning the taper the plans have you do practice threading on that area with 14 tpi before doing the actual 1/4-20 thread at the head. The rest of the operations I have already "explored" on my lathe.


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## Torque1st

*Re: My New Lathes.....*



KC2IXE said:


> first time you dial in, say a .125 cut on some 12L14 or something, and watch the lathe grunt slightly, and peal off the cut like it was nothing, THAT is when you really get perspective on the difference between say the LeBlond and a Mini-lathe.
> 
> There is one huge problem - you get used to being able to reduce a part .250 diameter at a time, and you go back to the mini-lathe, and you go nuts "Gahhh - I have to take 3-5 passes"


Try going from a lathe that will reduce a 20"dia chunk of 4140 down to 19" in one pass down to a mini...:mecry:

When I was in school we made a steel handle and bored it out and made a threaded cap to hold a center punch and chisel inside.


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## greenpea76

*Re: My New Lathes.....*

Hey darkzero,

Where is this class or CC located at? I might be interested in a Saturday class when one comes up. I'm down in LA area towards SGV.


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## darkzero

*Re: My New Lathes.....*

We finished our hammers today. The head was finsihed on the mill. First time I ever used a Bridgeport & I was confused as hell with all the different levers it has. :laughing:

The hammer was not hard especially for you pros but I'm very proud of it & I think it's beautiful! 














Next up is a C clamp which I'm excited about so I will really get to learn the Bridgeport & other full size mills. I'll change the thread title since I will be posting all the projects here. Damn, now I have to go & buy me a mill now. What did I get myself into!


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## olrac

Nice work Will! Look forward to your next posting.


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## big vin

how much for that hammer


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## wquiles

Great work Will - looks awesome!


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## precisionworks

> now I have to go & buy me a mill



No matter what you do, don't use the surface grinder or that will also go on the list.

Very nice work on the hammer. The taper on the handle really sets it off :twothumbs


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## PEU

very nice hammer, now I want to make one too 


Pablo


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## mossyoak

awesome, im taking a four semester program at the local CC for machining, and CNC machining the final two semesters, its very fun, but five days a week in the shop 730-300 is pretty damn demanding, nice job on the ball pein, i have to make on for my next project, brass turns for nicely.


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## Rothrandir

That hammer turned out beautifully! I really want to make one now too...


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## Mirage_Man

*Re: My New Lathes.....*



darkzero said:


>



Very nice Will! Those are beautiful. How did you do the radius on the one end of the head?


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## darkzero

Thanks everyone! 




big vin said:


> how much for that hammer


 
:laughing: As you already know, no way, I'm so in love with it that I want/going to make another so I can actually use one cause this one will be treated like a trophy. Looks like I will have to make two of everything. 





precisionworks said:


> No matter what you do, don't use the surface grinder or that will also go on the list.
> 
> Very nice work on the hammer. The taper on the handle really sets it off :twothumbs


 
Aw man don't tell me that! I'll get to use the surface grinders in the winter/spring session when making the V block & others. I always wondered what those magnetic chucks were mainly used for. There's also a horizontal mill that I will eventually get to play with. Even though I probably WILL want a surface grinder I don't think I would be able to get my own or have a place to put it. Aside from the mill that is already on my list I want a Baldor tool grinder too! I love that thing & wish I had one now!





mossyoak said:


> awesome, im taking a four semester program at the local CC for machining, and CNC machining the final two semesters, its very fun, but five days a week in the shop 730-300 is pretty damn demanding, nice job on the ball pein, i have to make on for my next project, brass turns for nicely.


 
Wow that's a lot of hours but I'm sure it will be all worth it assuming you have a high interest for machining. My courses will be slow learning since I can only take the Sat class but I plan on continuing with all the courses to follow. I think I might eventually take the NC & CAD courses for the heck of it too, well see then.


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## darkzero

*Re: My New Lathes.....*



Mirage_Man said:


> Very nice Will! Those are beautiful. How did you do the radius on the one end of the head?


 
I always thought a radius was done using a radius attachment tool like the ones that are used for turning balls. The first radius operation was on the end of the handle. First turned down the area to size & just used a simple a brazed carbide tipped radius tool like this: http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=2199548&PMT4NO=73101885 Of course they don't have any indexable tools (not that I have seen yet) which makes sense for the class. The majority of the cutters are Micro 100 brazed carbide. I think I will have to pick some up, only brazed tool I have is for chamfering.

The radius on the two ends of the head was also done with a concave radius tool but a much different one. The smaller end was first turned down with a 10deg taper. (For the handle we used a taper attachment for the cross slide set to a 1" taper.) The blueprint called for a 10 deg taper. So unaware I simply set the compound to 10 deg & turned the taper by hand using the compound slide. 

Rudy (the tool room guy) was walking by, saw what I was doing, & stopped to ask what I was doing. I told him I was turning the taper on the head. He said "interesting, yeah I guess you could do it that way". Told me I could have just used the taper attachment for the cross slide & set it to 10 deg & auto fed. Well what I didn't know was that the taper attachment had inch readings on one end & the other end had deg readings which I did not see cause it was hiding behind the headstock. Oh well, the taper wasn't very long any way & i was used to this as it's the only way I can turn a taper on my mini besides offsetting the tailstock.

After the taper I used a double ended concave radius tool. I suspected that it was custom ground for this purpose only since the ends were ground with a profile to give that basic shape. Each end was used to profile each end of the head. From what I remember it was probably about 1/2" in height & 1" in width & 5 inches long. I though it was pretty awkward seeing a tool wider than it's height. Again I figured it was custom ground but it had a Japan stamp on it. I'm sure it was somewhat custom ground specifically to profile the head but not sure what it started out as. I thought I had a picture of it but I'll take one of it next week.

After getting the basic profile I blended it using sandpaper. I cheated, when I got home I threw the head on my lathe & finshed it some more with finer sandpaper & steel wool. 


Here's a few pics I took with my phone.


Rough practice threading before turning the taper.







Taper attachment






Taper using compound






I really like using the Le Blond....








In regards to turning the taper on the handle. I started out using indexable tooling. I always thought using a smaller radius tip leaves a nicer finish & of course along with a slow feed rate. I'm currently happy using TCMT 31.52 & CCGT 32.51 inserts. I'm finding that the 1/32 corner radius leaves a nicer finish (appearance) than the 1/64 corner radius. 

With that said when I was turning the taper on the handle I was using a convex brazed tool that basically did not have a sharp corner radius. It left a very very nice finish. Most of the other guys did not mess with feed rates & I saw guys finishing the tapered area with emery cloth which did not look very good. On the Le Blond I set it to to the slowest feed rate .003 & both my brother's & my handles had the nicest finish in the class.

So is a smaller corner radius basically only good for turning sharp angles? What am I missing here?


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## darkzero

*Re: My New Lathes.....*

double post


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## KowShak

*Re: My New Lathes.....*



darkzero said:


> So is a smaller corner radius basically only good for turning sharp angles? What am I missing here?



When you feed very slowly a large portion of the insert's cutting edge is rubbing the part rather than cutting it/ Smaller radius inserts will rub less for a given feed, but as you've noticed your surface finish will not be as good as with a larger radius insert. 

An insert will have a minimum depth of cut and if you attempt to cutting less than the minimum the insert will rub instead of cutting, which wears the insert as well as creating a load of extra cutting forces, friction and heat. You're trying to push the insert into the part but not far enough to start it to cut, so something has to flex e.g. the part, the insert, the tool holder or the lathe. On thin parts or materials which work harden you'll run into problems.

There are "wiper" inserts which give a better surface finish than a normal insert, they have a complex corner radius geometry which ends in a larger radius. How this results in a better surface finish is difficult to explain without a diagram. Normally as you turn a part and feed your insert along, you get peaks between passes of the insert, faster you feed, the larger and further apart the peaks. The trailing edge of the wiper insert takes these peaks off, since it acts like a radius with a very large radius, several times larger than the main radius of the insert. The advantages of these are that you can feed faster for a given surface finish at the cost of bigger cutting forces, on big multi horsepower CNC machines speed is everything.


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## precisionworks

> I always thought using a smaller radius tip leaves a nicer finish & of course along with a slow feed rate.


Tip radius is one variable ... others include rpm, DOC, feed, workpiece material, tool overhang, etc. Some materials produce an awful surface finish, no matter what. Others, like Stressproof 1144, finish like glass regardless of speed or feed or DOC.

If you look closely at the CNMG-43x insert that quite a few of us use, you'll see that a shallow DOC plus a slow feed produce no contact at all on the tip radius - the contact point is the flat area behind the tip. To get a nice finish with that insert, DOC has to be deep enough so that the insert is cutting somewhere on the tip radius, with enough feed to keep the tip in contact with the work. On smaller machines with negative rake tooling, there may not be enough spindle hp to get the DOC & feed where they need to be. In that case, switching to positive rake tooling (which requires less hp) can get the insert into the "sweet spot" where it cuts well. Every insert maker publishes a list of DOC and feed, as well as sfpm, for each of their offerings. Staying close to the published numbers at least gives a good starting point.


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## darkzero

Finally back to some work today in the shop. Started my C-clamp project today (I'm choosing to stick with the BPs for now until I get comfortable with them). Started from a 1/2" x 2" x 4-1/4" steel plate.































The recessed area is where our names (initials I assume) will be stamped.



Got in a three new machines while I was gone. A new mill, horizontal, & vertical bandsaws. I'm very happy to see that the machining program is running strong here & still gets funding!



The huge vertical bandsaw (well to me anyway) was used for the very first time today on my C-clamp (not by me though).













The horizontal bandsaw is also a DoAll & is even larger than the old DoAll bandsaw. It hasn't been set up yet (still wrapped on the pallet), I'll snap a pic later when it's up & running.



This is the newest machine that is in the shop, a Sharp mill.







This is the new Ganesh mill that just came in.


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## wquiles

Nice shop indeed - I wish there was something like that where I live :twothumbs


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## precisionworks

Nice job on the C-clamp :twothumbs

In photo #3, the work is clamped on the extreme right side of the mill vise. That allows the left side of the moving jaw to rack in, which tips out the right side where the work is clamped. When possible, it really helps to cut a piece of scrap to the same width as the part & clamp the scrap on the left side.


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## darkzero

precisionworks said:


> Nice job on the C-clamp :twothumbs
> 
> In photo #3, the work is clamped on the extreme right side of the mill vise. That allows the left side of the moving jaw to rack in, which tips out the right side where the work is clamped. When possible, it really helps to cut a piece of scrap to the same width as the part & clamp the scrap on the left side.


 
Thanks, I'm definitely trying my best to take in as much information as I can, as fast as I can, without missing the important details but more importantly just getting the run time on the machines has taught me alot.

You know I pondered about that when setting up for the operation. I initially clamped the piece in the center of the vise with that very thought in mind. Then I thought about the ends of the C-clamp bending while clamped in the vise (that's what it felt like) & after milling then unclamping the ends would be distorted. 

No one qualified was around to ask so I went ahead with my decision knowing that the piece is not that critical to see what happens. I assumed it would have been worse if I claped it in the center of the vise. Turned out ok, I later told the instructor how I did it & agreed about the ends bending if clamped in the center of the vise. He said it was perfectly fine since we're not making space shuttle parts. :laughing:

Thanks for the tip Barry on how to do it "correctly" as I really wondered. Unfortunately the school doesn't have scrap pieces at our disposal to use this way but I'm willing to bring my own stock if it means for better results in the part.


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## StrikerDown

I was looking at those hammers thinking what a waste it would be for me to build something that beautiful... I would be unable to bring myself to hit anything with it! They are Sweet! Can't wait for the C clamp! :twothumbs


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## gadget_lover

Nice work. Personally, I hate using layout fluid and scribed lines because then I can see exactly where I missed the mark by an extra .005 or so. It happens to me most every time. 

RE the legs bending: If you do not want to keep a pile of scrap around to brace the other end of the vise jaws, consider that you can make a small machinist's jack (a screw and a threaded post) to use as a variable length spacer. 

A commercial version is at 
http://www.generaltools.com/Products/Machinists-Jack__07.aspx

No, I'm not recommending General Tools. They just came up first in the google search.

Daniel


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## StrikerDown

Two ?'s.

1- Isn't using scrap on the opposite side of the vise more to keep from racking the vise than bending the legs? (at least the way this item is clamped up)

2- Could this item be clamped with the backbone of the C clamp centered in the vise to avoid uneven clamping pressure? Or would this tend to bend the legs?

Daniel, I like the machinist jack idea, think I might make something like that.


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## darkzero

StrikerDown said:


> I was looking at those hammers thinking what a waste it would be for me to build something that beautiful... I would be unable to bring myself to hit anything with it! They are Sweet! Can't wait for the C clamp! :twothumbs


 
That's why you need to make two!  I too won't be using my hammer as intended. Instead I need to find a nice case for it. 




gadget_lover said:


> Nice work. Personally, I hate using layout fluid and scribed lines because then I can see exactly where I missed the mark by an extra .005 or so. It happens to me most every time.
> 
> RE the legs bending: If you do not want to keep a pile of scrap around to brace the other end of the vise jaws, consider that you can make a small machinist's jack (a screw and a threaded post) to use as a variable length spacer.


 
Oh so is that what those machinists jacks are used for?

I'm starting to love the smell of Dykem. It's the first thing I smell when walking into the shop on Saturdays & puts a smile on my face. It's like nitromethane or race fuel. I've grown to love those smells. A light smell of it smells good but too much & you get sick!

I think the layout lines are very useful & serve as good indicators assuming your part will be able to be finshed to remove the marks. Good to see if you are not hitting your mark. Also speeds up material removal as you don't have to use indicators or measuring tools when cutting to get close to your final mark especially when every caliper in the class/shop doesn't do a damn for measuring under 0.01". :laughing: Clean up can be a pain sometimes. Cleaning Dykem of off knurling on my brother's hammer was not fun.




StrikerDown said:


> Two ?'s.
> 
> 1- Isn't using scrap on the opposite side of the vise more to keep from racking the vise than bending the legs? (at least the way this item is clamped up)
> 
> 2- Could this item be clamped with the backbone of the C clamp centered in the vise to avoid uneven clamping pressure? Or would this tend to bend the legs?
> 
> Daniel, I like the machinist jack idea, think I might make something like that.


 
1. That's the impression I was getting by Barry's post.

2. That's the impression I was getting & felt like when I did that.

Now that I think about it, assuming I had scrap on hand to use, I suppose another way would be to position the backbone of the C-clamp in the center of the vise & use scrap that is about the same width as the backbone in between both sides of the C-clamp & the vise jaws. This would prevent the jaws applying any pressure to the legs.


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## precisionworks

Most of my vise set ups are centered in the jaws, so the need for a spacer is every now & then. When one is needed, a piece of 1" round bar is sawed off slightly long & the ends are faced off, so it's easy to match the length of the part +/- .001". After the job is done, the spacer gets marked for length, in case that same job ever comes back.



> I suppose another way would be to position the backbone of the C-clamp in the center of the vise & use scrap that is about the same width as the backbone in between both sides of the C-clamp & the vise jaws. This would prevent the jaws applying any pressure to the legs.


The way you set it up was as good a method as possible. The force from the end mill was pushing toward the vise jaws, which is perfect.

The best thing to remember any time you need a new or untried method to fixture a part is "Does it look solid". If it does not, or if you get even the slightest hint of movement when the tool touches the metal, STOP. Same thing if you hit the start switch & get that funny feeling in your stomach that something isn't right. Taking a few minutes extra to get a rock solid set up can save a part in which you've already invested an hour of machine time. It can also help avoid an injury.


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## bluwolf

Will,

That is some great work. The hammer looks terrific. 

I'm with Mr. Quiles, I wish there were some classes like that around here. There was a Vo Tech school that did quite a few years ago, but it got shut down :sigh:

Mike


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## darkzero

Finished the c-clamp. Handle & end caps were made out of drill rod & were pressed fit together (I cheated & made them at home). The pad was "peened" for mounting. My thread is class 3, my brother's was about class 2 as he had to chase it with a die. Not perfect all around but pretty good for my first mill project & I'm happy with it. 


















Some other pics:






















Class is over but I'll be back there in February.


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## wquiles

Nice work Will. It is great to have access to such machines :thumbsup:


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## mossyoak

dude, i swear we have the same exact project list, that c-clamp is what i start on after christmas break


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## PEU

why most C clamps use square threads? I just happen to have an el cheapo C clamp here at my desk and it has regular threads.

BTW, beautifull work you did (again!)

Speaking of school shops, and old friend from high school sent me pictures (Link) he took last week of the technical high school we attended, I got depressed by the fact that no new machines were added and they still do the same I did more than 20 years ago (a hand made hammer, a BBQ grill, a wooden suitcase) I mean, these are OK to know, but nowadays that knowledge is not near enough to enter a shop as apprentice... :sigh:


Pablo


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## mossyoak

PEU said:


> why most C clamps use square threads? I just happen to have an el cheapo C clamp here at my desk and it has regular threads.
> 
> 
> Pablo



Its because square threads are stronger structurally, the clamping action puts all the force on the side of the thread, and it being flat opposed to angled makes it stronger and more resistant to wear.


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## sortafast

man after looking at this thread I really want to go back to the Machine Mfg program at the local community college, but its fricken $74 a credit hour and for the $$$ I would spend to learn a few tricks (and a lot of stuff I already know), it just ain't worth it. Besides, I could take the money that I would spend on classes and buy better machines and tools.


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## precisionworks

> pretty good for my first mill project


That's much nicer than most anything I do for a paying customer 

Awesome job.


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## darkzero

Thanks everyone. 

I was actually thinking about "using" this one but now maybe not.


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## bluwolf

darkzero said:


> Thanks everyone.
> 
> I was actually thinking about "using" this one but now maybe not.


 
Very nice Will, I know I wouldn't use it.

Mike


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## Vee3

Brings back memories. I used to teach machine shop classes part time at LA Trade Tech and El Camino College.


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## darkzero

Vee3 said:


> Brings back memories. I used to teach machine shop classes part time at LA Trade Tech and El Camino College.


 
Very cool! My other little brother went to El Camino. This class is at Pierce. :wave:

I'm also thinking about taking the machining program at Simi Valley occupational since it's close to my work. Are there any others?


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## Vee3

darkzero said:


> Very cool! My other little brother went to El Camino. This class is at Pierce. :wave:
> 
> I'm also thinking about taking the machining program at Simi Valley occupational since it's close to my work. Are there any others?




I'm kinda out of the loop as far as the local schools (other than El Camino) go these days. EL Camino is still great as far as teachers, facility and equipment. I've heard good things about Harbor College and Pierce in the past. SCROC in Torrance used to be where a lot of guys went (one of my LATTC students became a CNC instructor there years ago), but IIRC they no longer offer MTT courses. LATTC's MTT program was falling apart when I left in 1996; I don't know if it's improved or not.

Most of the good MTT programs in SoCal have been cancelled over the past ~20 years. Hard to compete with Asia, imported labor and lousy CA manufacturing business climate here. Most all LA area high schools have shut down their machine shop classes due to liability issues, so new students getting involved in manufacturing are few.

Really good machinists will never go hungry though. There aren't many left in the US because we're not bringing up many new ones. However, we still gotta make some stuff here...


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## KowShak

Vee3 said:


> Really good machinists will never go hungry though. There aren't many left in the US because we're not bringing up many new ones. However, we still gotta make some stuff here...


 
China certainly can manufacture things cheaper than the US or Europe because labour in China is cheaper but that won't be the case forever. Economic development means pay rates in China are increasing year on year, eventually they'll get to the levels where it isn't cheaper to make things in China and ship them to around the world. The developed world needs to maintain a skeleton manufacturing base so that when it's as cheap to make things at home as it is to ship them from overseas, we can start making them here. In short, going into manufacturing might sound like a stupid move in the short term but in the long term its going to pay dividend, especially when manufacturing wants to grow and there is a shortage of trained / skilled / experienced people.


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## darkzero

Completed my first NIMS project, vertical mill & surface grinder. Of course I would've failed because I didn't meet a few of the tolerances on the blueprint but it was more than adequate for passing the course & decent for my first time. Still 8 more weeks to go though so I'm going to do another NIMS shaft project that's not part of the course which will be done on a lathe.

I have no idea what purpose it serves but it was very good practice. It's called a "title block". :thinking:








Squaring the block after using the coax & test indicators to get the table, head, & vise in line.






Milling the steps & slot











Drilling the dowel pin (?) hole. I screwed this up & went oversize when using the Centurion boring head so I couldn't use a 3/4" reamer. I cleaned up the hole at home on the lathe with the 4 jaw & boring bar. 







My first time using the surface grinder. It was fun but quickly got boring but I enjoyed it as it was a new learning experience. I did ok since my part didn't go flying out the window. Barry was right, I want one now but that's just a dream for now.


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## csa

Looks like a lot of fun. I wish I had taken more advantage when I had easy access to a shop like that. Now I don't have time...


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## Mirage_Man

Wow! You're sure getting a great bit of experience aren't you? I wish I had the time to take a class like that. Maybe when my son is grown I will.


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## precisionworks

> went oversize when using the Centurion boring head


Probably the easiest mistake there is ... most bars have some springback, depending on the DOC per pass. When the bore is close to spec, around .010" under, try two passes through the bore without adjusting the dial. The first pass takes the normal (expected) amount and the second pass removes the springback - often quite a lot, depending on size of bar, DOC, length of bar, etc.

Lathe boring often allows use of a bigger diameter bar, but there are many times when mill boring is the only option.


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## darkzero

Thanks Barry. Yes springback was an issue using the small boring bar. The corner radius was also very small & I did not feel like regrinding it so paired with the springback it left pretty deep fine grooves. Didn't care much cause I was going to just ream it until I went oversize.

I can see how the boring head is ideal but sometimes it sucks having to do a pass, stop the spindle, advance feed on the boring head, do another pass, then repeat. Although I can understand why this wouldn't be ideal but does it ever makes sense to just use a boring bar in a collet & use the table to advance for the cut?


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## gadget_lover

darkzero said:


> I can see how the boring head is ideal but sometimes it sucks having to do a pass, stop the spindle, advance feed on the boring head, do another pass, then repeat. Although I can understand why this wouldn't be ideal but does it ever makes sense to just use a boring bar in a collet & use the table to advance for the cut?



If you are proposing that you move the X-Y to make the hole, you will end up with an eccentric one.

The adjustment of the boring bar changes the offset of the cutting edge from the center line. It effectively increases the radius of the cutting edge.

You can get good, round holes using an end mill and a rotary table, but it's easier to use a boring bar.

Daniel


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## darkzero

gadget_lover said:


> If you are proposing that you move the X-Y to make the hole, you will end up with an eccentric one.


 
Thanks Daniel. Now that I think about it after what you said you are correct. Don't know what I was thinking as it doesn't make sense.


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