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View Full Version : Does such an end mill exist?



beanbag
05-24-2010, 07:24 AM
I'm looking for an end mill that can do deep pockets and side profiling. In practice, the tool for this job is a carbide reduced neck end mill. However, the problem is that the reduced neck forces you to run it at that length for all cutting jobs. I was thinking instead, to have an end mill with a long shank, of say 3/8" diameter, and a short fluted section (1/2" LOC) that was something like .400" diameter. This way, you can stick it out of the collet as much as you want for the deep pockets, and retract it for less deep pockets. I think MariTool at PM once offered to make these, but nothing came of it.

oldtiffie
05-24-2010, 07:53 AM
Tee-slot or Woodruff key cutter?

http://www.google.com.au/#hl=en&source=hp&q=tee+slot+cutters&aq=0&aqi=g2g-sx8&aql=&oq=tee+slot+&gs_rfai=&fp=96e43c1db0d92f02

http://www.google.com.au/#hl=en&q=woodruff+key+cutter&aq=5&aqi=g10&aql=&oq=woodruff&gs_rfai=&fp=d47e02d8a2497605

Evan
05-24-2010, 08:43 AM
Side profiling (especially undercuts) is the realm of carbide burrs. The are usually only side cutting except for the ball or cone end type. They work very well and are much like a rotary file except the stock removal is much faster.

http://metalshopborealis.ca/pics5/burr.jpg

http://metalshopborealis.ca/pics5/burr2.jpg

http://metalshopborealis.ca/pics5/burr3.jpg

strokersix
05-24-2010, 08:53 AM
Some endmills have reduced shank. 7/16 for example often has 3/8 shank. Maybe this can help you.

Carld
05-24-2010, 09:02 AM
beanbag, how long of a shank are you talking about.

First off a collet is not good for holding a long shank and cutting at a distance from the collet. The cutter will wobble in the collet and you won't get accurate work.

Second off the collet can only take a short length inside before it hits the drawbar end.

The best holder would be a custom made holder you could slide the cutter in and out of and rigid enough to handle the side thrust a long shank would give.

strokersix
05-24-2010, 09:51 AM
I rarely use a collet for end mills, prefer end mill holders. I often grind a second flat on the end mill shank for extended reach.

I've had end mills walk out of collets more than once. Never had one walk out of a holder.

bobw53
05-24-2010, 11:21 AM
Maritool has them, for AL and in a Variflute for steel. Necked back .010 to .020 or so, the whole shank. Prices are pretty good comparatively.

Harvey Tool also has them, but they are necked back a full 1/16, and at $170 for a 1/2" I'll pass.

I've had good luck with the Maritool reduced shanks. Just bought 2 .75 inchers for a job, they held up really well, actually one of them held up well, the other is still in the package.

Strokersix already said it, but if you aren't going very deep, you can just hang a standard endmill out a little further, I grind extra flats also. If finish is a concern you just grind 'em back a little. Pluses are standard cheap endmills, downfall is that once you grind that endmill back, you can't chuck up on it shorter for another job.

Circlip
05-24-2010, 11:58 AM
You can always hold it in a drill chuck.:rolleyes:

Dr Stan
05-24-2010, 12:00 PM
You can always hold it in a drill chuck.:rolleyes:

I do hope you were being sarcastic.

Circlip
05-24-2010, 12:41 PM
Weeeeeeeeeell Dr Stan, I always thought it dangerous, but since joining this site, I've seen the light and been re-educated.:o

Dr Stan
05-24-2010, 01:22 PM
Weeeeeeeeeell Dr Stan, I always thought it dangerous, but since joining this site, I've seen the light and been re-educated.:o

Good. When I taught machining at a vo-tech I made sure my students did not hold end mills in a drill chuck and knew why they should not do so.

It's an excellent way to damage drill chuck jaws.

Carld
05-24-2010, 03:15 PM
and other things as well:eek:

Scishopguy
05-24-2010, 03:49 PM
Milling using a drill chuck usually is a result of being in too big a hurry to change out the chuck for a holder. I learned the hard way years ago and got yelled at by my boss to boot. :sad: Something about having that chuck come off the taper and spin madly about the floor, with the end mill still sticking out, taking chunks out of table legs, just tends to make a believer out of you. :eek:

vpt
05-24-2010, 05:00 PM
I have had good luck holding end mills with a 4 jaw chuck :eek: but with a cut up pop can to act as a sleeve around the endmill for bite so it doesn't come loose.

I do the same with my unimat 3 jaw chuck and endmills.



http://img62.imageshack.us/img62/9714/texas056.jpg

beanbag
05-24-2010, 05:15 PM
beanbag, how long of a shank are you talking about.

First off a collet is not good for holding a long shank and cutting at a distance from the collet. The cutter will wobble in the collet and you won't get accurate work.

Second off the collet can only take a short length inside before it hits the drawbar end.

The best holder would be a custom made holder you could slide the cutter in and out of and rigid enough to handle the side thrust a long shank would give.

Well, for a recent job I needed to make a pocket 1.6" deep with 3/16" radius on the corners, i.e. using a 3/8 end mill. My normal 3/8" endmills only had LOC about 1" and I checked that rubbing would have been a problem if I tried to go deeper. I ended up using one of my HSS end mills that was 13/32 on a 3/8 shank, and having the end mill stick out of the collet a little more than I like. (the corner radius was a little larger than planned, but oh well) I suppose I could have also bought a long LOC 3/8" carbide end mill as well.

The reason I like reduced neck instead of extended flute length is that they are more rigid, and since there will be no rubbing over the previous cuts, the pocket or side profile won't have a slight taper to it.

The CNC machine I use has a R8 collet system, and I think you can stick shanks at least 2.5" or so deep in them. ( I don't have a collet in front of me right now to check) What kind of a custom holder would you suggest?

Evan and Oldtiffer:
Thanks for those suggestions, but those cutters aren't general purpose enough.

Bob: The maritool cutters have a non-standard shank diameter, so I'd have to additionally buy some kind of end mill holding thing. Or would a shimming sleeve over the shank work?

MuellerNick
05-24-2010, 05:35 PM
Sure they exist. Here, shaft diameters are 6, 10, 12, 16, 20 mm. If the mill's diameter is different than the shaft diameter, it mostly is bigger. So a 13mm mill will have a 12mm shaft.


Nick

fasto
05-24-2010, 06:03 PM
Well, for a recent job I needed to make a pocket 1.6" deep with 3/16" radius on the corners, i.e. using a 3/8 end mill.
I would have used an extended reach EM. For example, KBC tools #5-221A-80121 is a Niagra Cutter 3/8 dia ball end with 1" LOC and 2.25" long reduced diameter above, with a 3/8" shank to clamp (5" overall length). If 1" LOC is too much, you could grind the flutes off above the ball end to reduce it to your liking. If you don't need 2.25" reduced diameter they have shorter versions, too. If you don't need a ball end they've got square ends. If you don't like KBC buy it from someone else :).
Collet wars: I can't imagine clamping this in a collet of any sort and having trouble with it. If you do, the collet is junk! Toss it and get a new one. They are consumable, even Hardinge collets wear out. Or you can do what I do and use TG collets.

Fasttrack
05-24-2010, 07:31 PM
I have a solid carbide 4 flute endmill. It is a 3/4" diameter with a 3/4" LOC and a 3/8" diameter shank ... 5" long.

It came out of Boeing surplus. :o I bet that helps you a lot, doesn't it? :D