# Which endmills?



## mototraxtech (Jun 20, 2010)

I am currently designing a part for the lathe that will attach to the carriage and allow me to chuck a end mill and notch tubing. the question is there are so many different types of end mill I don't know which ones to use. I will mostly be using a notch size of 1" to 1-1/2". Any help from you experts would be much appreciated.


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## 65535 (Jun 20, 2010)

A lot of guys use a hole saw of the appropriate size, I would have some reservation about putting an end mill in a lathe chuck, but I guess a straight shank 4 flute would be the way to go.

Definitely get a second opinion from Barry though, he is the go to guy. I'm sure with welding and machining he's done plenty of tube notching, wouldn't be surprised if he said, drill press/mill.


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## precisionworks (Jun 20, 2010)

> wouldn't be surprised if he said, drill press/mill.


+1

Years ago I bought the Ol' Joint Jigger (what a name ) Model RTN-1000. Not cheap but it works really well, and someone with a mill & lathe could copy the design. 

http://www.aircraftspruce.com/catalog/topages/notchers.php

It's also easy to notch in the mill vise - find center of the tube and use a bimetal holesaw to make the cut. Speed for bimetal hole saws is pretty low, according to the tech people at Lennox - about 75 SFPM, which is tough to do without a VFD on the mill or drill press.

There are a number of end mill notchers available, and most use a rougher & do all the cutting with the side of the tool - here's a video showing one: http://video.google.com/videoplay?docid=1119532238085942928#


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## darkzero (Jun 21, 2010)

I'm very curious to see what you come up with. I know they have those mill attachment for lathes (mostly for minis) but it just seems awkward to put an end mill in the chuck of a lathe.

When I worked as a mechanic there was a label in my Snap On dealer's truck that I never forget. "Always use the correct tool for the job......" This is very true, I can't tell you how many broken tools (which also leads to people getting hurt) when not using the appropiate tool for the job. I'm guilty & have learned lessons from doing so.

Perhaps you might have a good design in mind but just thinking about using a lathe to notch tubing just doesn't seem to make sense.


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## 65535 (Jun 21, 2010)

With a collet chuck and stubby end mill maybe I could see it working, but the idea seams a bit haphazard. My main concern would be, you have a possibly large pipe moving in relation to a spinning tool, usually it's easier to use a hole saw and move that into the piece.


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## precisionworks (Jun 21, 2010)

> you have a possibly large pipe moving in relation to a spinning tool, usually it's easier to use a hole saw


+1

If you look at available end mill notchers, all are heavy & massive, with most costing around $5k. Side milling, even when using a heavy milling vise, is not a gentle operation. A bimetal hole saw, held in the lathe chuck, would be worth looking at - as long as the pipe can be fixtured to the cross slide. 

There are ready to finish castings available that let you build fixtures: http://www.statecollegecentral.com/metallathe/index.html


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## KC2IXE (Jun 21, 2010)

precisionworks said:


> +1
> 
> ...snip...- about 75 SFPM, which is tough to do without a VFD on the mill or drill press.



I'll also +1, and a LOT cheaper than end mills

And doesn't that "hard to do" depend on the drill press? I mean, where I learned to run a lathe/mill, we had a BIG old Buffalo Drill press - when I say BIG, it was about 10 ft tall, and there was no problem putting a few hundred pound item on the table. Used MT5 tooling - we used to keep it set to around 40 RPM for most work, as changing the belts around was a dog - I THINK it had a 5HP motor, but who remembers after 30 years

One day, one of the shop idiots (we used to say you had to remind him which end of the paintbrush to hold) didn't clamp down the 10 section of 6" wide flange I beam that he was drilling, despite 3 of us telling him "clamp that beam" - the bit grabbed, and yes, the beam started to swing around like you've seen small stuff do. He got lucky, he was on the "safe" side of the beam, it ONLY put a good sized diviot in the brick wall, and broke a NOT inexpensive drill bit


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## unterhausen (Jun 22, 2010)

I'm building an attachment for my lathe to notch tubing. I am not making a full sliding table like you would use for a milling attachment. I keep cutting corners and haven't got the thing working right yet, but I had a set of collets in my junk collection that fits all the sizes of tubing that I'm working with, so I am incorporating that, a sliding table, and a right angle plate to replace the compound. I'll take some pictures when I get my act together.


I am cutting very thin but high strength tubing. Most people that do that use fine tooth hole saws. Missouri tool carries a Spanish brand that works pretty well. I use a Paragon machine works mandrels 




precisionworks said:


> There are ready to finish castings available that let you build fixtures: http://www.statecollegecentral.com/metallathe/index.html


I looked at Metal Lathe Products for this, but I already had most of the stuff I needed in my junk box. I may have screwed up, but it just seems like there is a lot of machining to do on those castings. Great guy to deal with though. I met him at NAMES in Michigan, which is funny because he lives less than 10 miles from me.


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## mototraxtech (Jun 22, 2010)

I don't see an problems doing what I want as I have already made a drill press attachment and in works fine. Why would holding an end mill in the chuck be an problem at all. I don't really see that being a bad thing. As for using the right tool for the job I agree. And the right tool for me is the one I am making because it should be much faster to setup and cut as well as cheaper and saves me room.

I really didn't want to use hole saws as you can not cut very large angles with them unless you turn the part around which will not be possible. I have seen some really nice hole saw tube notches but they run 600 dollars and I can make this one for around 200 and it will work better for me.

The only way a hole saw can be use is if I can get some deep hole saws. But once again why is the end mill idea very bad. How would it be any different than mounting a end mill in a milling machine an them notching a piece of tubing that way.

Oh and I just looked at a bunch of end mill hole saws and most are roughly the same size as my lathe in weight and foot print so I am pretty sure the size and stregth of my machine will sufice espesially since I am only notching up to an .125 wall tubing.


Thanks for the help.
So far either hole saws or a 4 flute end mill.


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## unterhausen (Jun 22, 2010)

I think I would go with as many flutes as I could afford.

what will be successful for you really depends on how stiff your lathe is, mine isn't very stiff at all.

I'm cutting 1 1/8 or 1 1/4 diameter tubing. The wall thickness is .9mm or thinner. Material is hardened steel or 4130. It really can make a mess and break expensive parts if you don't have a lot of teeth. There is a lot of force per tooth if you only have 4 teeth per rev. I'm just copying what I've seen people do successfully.

A hole saw can go as deep as the length of mandrel sticking out of the chuck, the link I gave gives some mandrels that are pretty long.


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## mototraxtech (Jun 22, 2010)

After looking at the actual tube notching machines it appears that they use end mills with little threaded ribs on them. I think they are called roughing end mills. I think I will try them and if all else just use some hole saws.


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## unterhausen (Jun 23, 2010)

roughing mills cut way down on chip loads. 


I think I got my setup machined today, but it's at work and they have all the roads shut down for paving so maybe I'll post pics tomorrow. I'd like to see what you have come up with.


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## mototraxtech (Jun 23, 2010)

I wont be able to build it until the end of summer as I have some school bills that must be paid but you bet it will get the full picture show once I get it going. Maybe even a video!


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## olephart (Jun 23, 2010)

mototraxtech said:


> Why would holding an end mill in the chuck be an problem at all.



Because it's not safe. Lathe and drill chucks can not hold the milling cutter properly against vibration and high cutting forces. The tool will move in or out when the chuck loosens or holding ability is exceeded. Milling cutters have departed their desired location on more than one occasion when used this way. It's quite exciting.

I don't think you will find a commercial mill or pipe cutter that is designed to hold a milling cutter in anything but a collet. There is a reason for that. Otherwise, wouldn't it be easier to use an accurate, keyless chuck for everything? All this is not to say ya can't get away with it, or maybe not.


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## mototraxtech (Jun 23, 2010)

So what if I just used a collet in the end of the chuck to grab the end mill. Or how about if I picked up a collet chuck for the lathe and then a collet for the end mills I use.

Sorry if I'm not quite getting it but for the slow speed none commercial use I am using I don't see the problem. I have used so really misaligned milling machines in high school with some one inch end mills and never had a problem. I wasn't even using a collet as I didn't know I was suppose to. I cant see the problem with do this.

Not trying to contradict you guys I just don't foresee there being that big a a problem with using them. What would the difference be in using a then walled low strength hole saw over a heavy thick end mill.


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## precisionworks (Jun 23, 2010)

> What would the difference be in using a then walled low strength hole saw over a heavy thick end mill.


A hole saw in compression will support hundreds of pounds of pressure, as will most tubular structures in compression. Plunging on a mill (or drill press or lathe) uses the strongest axis of the machine, where the full diameter of the bearings absorbs the axial (thrust) load.

An end mill works well in plunging, and plunge milling is a common operation. No drama, as the milling cutter is being fed through the part using the strongest support of the mill or lathe. Side milling is a different story - the forces are all radial, so one side of the bearing race gets all the pressure & has to provide all the opposition to the part being fed into the side of the end mill.



> I wasn't even using a collet as I didn't know I was suppose to. I cant see the problem with do this.


Any lathe chuck (3 jaw, 4 jaw, 6 jaw, etc.) has just a handful of tiny contact areas that grip the tool shank. Not to say it can't be done, but any other holding method is better - with a 5C collet being probably the best available. A collet chuck for a lathe cost only about 2X the cost of the Ol' Joint Jigger 

I wouldn't try what you're suggesting. Every commercial unit is purpose built to support the huge radial loads imposed on the tool & part, and to securely hold the tool. A hole saw held in the lathe chuck is many times safer. Our Resident Photographer did insist the if you get bloody you must post the photos here. Broken tooling is OK, but not nearly as spectacular


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## gadget_lover (Jun 23, 2010)

Not advocating anything but....

Most lathes have a taper inside the spindle. An mt3 taper endmill holder is not hard to find nor is it expensive. I have a handful of them that swap easily between my mill and lathe. Since I have a larger mill I almost never use an endmill in my lathe any more.

Daniel


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## olephart (Jun 23, 2010)

2 things.

1. Just because some folks seem successful with a marginal/unsafe procedure doesn't make it more safe. Example: Texting while driving.

2. Things don't always happen like you think they will. Example: I watched a guy cutting a 1/2" deep slot in a large piece of aluminum. He was on a Bridgeport with proper collet and using a 3/4" end mill.

Between 6 and 10" of travel, the slot deepened from 1/2" to almost 1". Turns out the collet was not tightened properly. I doub't you would expect the cutter to go deeper into the work. It did. Another foot of travel and it may have been flying around the shop.

It seems to me there is enough information presented to cause you to do some research and make an informed decision to proceed with your plan. Personally, I think you can do it using a chuck if all goes well. I wouldn't be in the shop while you are doing it. That's just my choice. I don't text while driving either.


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## unterhausen (Jun 23, 2010)

I'm not sure what's so dangerous about using the endmill, is a broken endmill at low speeds really that much of a hazard? I am thinking a lathe isn't rigid enough, and something will break


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## mototraxtech (Jun 23, 2010)

OK so some food for thought. First off after looking at the hole saw arbor website and the cost of some decent hole saws I think I will try that first. If however I am not satisfied with it I still may go to end mills. Thank you for explaining why the cutter in the chuck would not work. I have always been they guy to take advice from people more experienced than myself which is why I asked hear. But I like to learn why it would and not just that it wont.

So if I was to use a collet chuck to hold the end mill this would be fine or no. Also maybe set up a collet holder for it but I do not think my lathe spindle has a taper.

Lastly, it was mentioned that plunging with and end mill is not to stressful so what if I just ran the tube to be notched straight into the end of the end mill going toward the chuck.

Thanks for all the help and EXPLAINING why it wouldn't work. I would have never though about the low contact area causing the bit to slip until it probably happened.


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## 65535 (Jun 23, 2010)

Well if plunging (the proper method) a hole saw is the best tool, as it only removes a thin cross section around the arc. 

Really a Tube notcher is a better free standing unit, be it homemade or bought. I'm sure you could find a design or plans for a hand drill powered notcher, I know I've seen them around.


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## precisionworks (Jun 23, 2010)

http://chopperhandbook.com/neatstuff/cbh-notcher.pdf

http://chopperhandbook.com/neatstuff/cbh-notcher.htm


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## olephart (Jun 24, 2010)

unterhausen said:


> is a broken endmill at low speeds really that much of a hazard?



I doubt that would hurt anything pink and tender. But, the failure mode I have been referring to is not breakage. I'm referring to the entire cutter departing from the chuck at high speed. It's sorta like starting up a lathe with the chuck key installed. It happens while cutting the work piece. Seems like that would hold it in the chuck, but it don't.

You can pay attention to speed, feed and depth of cut and probably get by with using a chuck for a lot of milling operations. Lots of people do. At least be aware of the problem. Put some fingernail polish where the mill meets the chuck so ya can see if it's moving. It's not an instant thing. Takes awhile to develop.


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## precisionworks (Jun 24, 2010)

> probably get by with using a chuck for a lot of milling operations


I sometimes use my keyless drill chuck (in the mill) to hold a *small* end mill when making one or two shallow cuts, .050" or so. Usually works.

Pipe & tube notching produces forces that are at least one order of magnitude greater, possibly more depending on your particular cutting data. All lathe chucks, whether 3/4/6 jaw, have the smalles of contact areas, with probably 10% of the work piece (or end mill shank) in contact with the jaws. End mill holders raise that number to about 75% contact, collets raise it to around 90% contact. Milling forces are primarily radial for side milling, axial for end milling, and collets do the best job retaining an end mill - short of heat shrink tool holders.

You can easily make a straight shank end mill holder for lathe use. Start with round stock just under the through hole size for your lathe chuck. Mill three flats on the OD that are 120 degrees apart. Ream a hole for the end mill that's .0002"-.0004" larger than the end mill shank, and drill & tap two set screw locations to bear on the Weldon flats. Not as good as a collet but many times better than the chuck.


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## kd5ahl (Jun 24, 2010)

why not use hex stock? Then all you need to do is bore a hole for the endmill and drill and tap 2 setscrew holes.


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## precisionworks (Jun 24, 2010)

> why not use hex stock?


Great idea 

If I were making one (having a welder) it would be even easier to bore the hole about .0005" too small, warm the sleeve, cool the end mill, & press fit the end mill into the sleeve. Weld the end of the shank to the end of the sleeve. You'd never have to worry about the grub screws coming loose.


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## olephart (Jun 24, 2010)

Seems like any of those ideas would work. I made a collet holder for 5c collets to address the problem. About as easy as other options. My lathe has a threaded spindle, so it was simple.

I just threaded a piece of round bar to fit the spindle and made the rest of it in place. Can't get more accurate than that! It closes by tightening a "nut" against the face of the collet rather than pulling from the rear.

Once you attach the stock to the spindle, ya bore a hole for the collet body and cut the taper. Then thread the end to accept the "nut". Ya make the nut so it contacts the outer edge of the collet when tightened and drill holes in both parts to use a "Tommy bar" to tighten it. 

It's a nice project to consider and results in a low cost, but very precise method of holding stuff.


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