Grinding flats on endmills

[mike_f]

We use milling chucks made by Schunk, they have a shorter gage length than anything else I've found in the market. You can also use them with end mills that have flats ( yeah, I know what your thinkin')..but it's true, I've been using them for years, with and without flats, with no damage. Step down collets are available and I haven't found any issues with increased run-out when using them. We've done some HEAVY milling with them and have NEVER pulled out an end mill. They kick butt...

 

regards

mike

[Dave.L]

Mike,

 

Are these Tribos, or hydraulic? Or better yet, what Schunk P/N are they?

 

Thanks,

 

Dave

[mike_f]

Hi Dave,

These are the SINO-R holders. A typical holder for us..CAT-40 3/4 dia. is P/N 209 614

Schunk calls them "universal holders". they are mechanical milling chucks, not hydraulic. I've tried all kinds of milling chucks here and these are the best I've used. HTH

 

regards

mike

[Dave.L]

Thanks Mike.

 

-Dave

[Mastercam Mike]

Has anyone tried sweat fit holders? They worked well for me.

[MotorCityMinion]

I had an HSK heat shrink holder loaded 180. deg off on a Makino. The Makino usually alarms out when this happens, but on a few occasions, it won't until you try to tool change. Very dangerous indeed. At 20k, it sounded like a star trek teleporter and the machine felt like it was hovering. I was actually just as nervous when I stopped the spindle, thinking that it might toss the tool.

[mcpgmr]

We use heat shrink up to Ø.500. Collets work fine for Aluminum provided your not roughing. It depends on your D.O.C. If my only option was a solid weldon type holder I'd grind a flat. Nothing more embarassing then explaining to the boss that the tool pulled out of the holder and scrapped a part while cutting Aluminum. I like to rough everything with a flat e.m. when the geometry permits and finish with a ball e.m. if I'm surfacing that is. Justin, When I worked at you sister company we used those three flute powder e.m.'s that had the weldon style flats on them for roughing. Those e.m.'s were awesome for roughing Aluminum and lasted forever. I forget who makes them. Good luck!

[Justin Beebe at Folsom Tool]

Paul,

 

The brand we use now is Cleveland. They are three flute powdered metal roughing endmills and they work really well. Sometimes they come shipped under the Kennametal name but I'm pretty sure they are the exact same endmill. They do have weldon style flats on them. I won't run a roughing endmill without a flat and even now we are starting to tell our suppliers to grind flats on our aluminum finishing endmills. They are already ginding radii on some of them so it's not to much more for the flats. I really don't like to grind them and breath in all that carbide dust. Like I said I haven't had one pull, push, or spin in two years but I guess a flat can't hurt especially if they are ground correctly.

[Hymen]

-- For real heavy cutting we use Iscar low boy holders.( I'm not sure what ther are called) The whole collet is inside of the holder. Use a 1 7/16 box end wrench and get it as tight as we can.---

They are called SHORTIN Holders.

You can crank down like hell on these and you won't pull your tool out!! + there is very minimal runout when using a good collet.

When you use a side lock you sacrifice tool life due to runout and the tooling extension. Of course mill chucks, hydro and shrinkers work great for the high HP cuts as well but there are the associated costs that come with them.

[Dave.L]

over-tightening is not good, it's actually bad for the collet. A torque wrench should be used and set to the mfg torque specs.

[PaceToolmaker]

We have 2 Makino's that both have a 20,000 rpm HSK spindle and we went for the press in holders over the shrink fit.For hard milling i use the press in holders.No runout and the load time is faster than the shrink fit in my opinion.Althought for long reaches i believe the shrink fit has more options.When cutting mag or aluminum prototypes we use er-16-20 collets.When hogging these protos,i like the Nikken millchuck as it seems to dampen it a little bit.The only side lock holders we use are in our older Fadals and i never grind a flat on the tools and have never seemed to needed one.

[Guest]

With side lockers, if you not grinding flats and not moving your tool, you're not machining hard enough.

 

[connormac]

Thanks Hymen. Those are the ones we use. They work great. We are going to have to to go to heat shrink for special job.

[Hymen]

Dave, I do agree that cranking down on collets is bad for them especially if the shank of the tool does not fill the entire collet or if they have flats of any kind! But this is a cheap alternative to Mill chucks, shrinkers, and Hydo's for those high horse power cuts! Aside from the fact that your tool and holder extension is now at a minimum, creating a stabler cut, the versatility is greater.

 

connormac, check this out for your shrink needs. Another cheap alternative to buying an entire CAT** Shrink holder. ER32 shrinker. The biggest benefit I have found is that when the holder is at it's shrinking end, won't hold the tool sufficiantly, you don't buy a new holder just the ER32 shrinker piece at a little more cost than a precision collet.

after you get these a little more than hand tight, chuck it up in the spindle indicate the tool in by tapping on the shrink part, then remove and tighten down. It's dreamy!

[connormac]

Hymen,I will check out the ER32 shrinker. Might work well for what we are going to do. Thanks for the advise.