What holder works for chatter free endmills?

[AplusWizard]

I am currently shopping for a tool holder. We are trying to decrease our cycle time on machining some 8620 gears. To test out some new cutters, I faced off the ends of a slug of 6" diameter 8620 in the lathe & then grabbed it in a vise and started going at it. I have a few chatter free design roughing tools that I was testing like Hanita, Iscar and a few no-namers like Tycarb & Deboer. With the Hanita I was slotting the slug at 2300 RPM & feeding at 33 IPM at 3/4" deep depth of cut. It produced beautiful chips and I was using up almost of the HP my machine had (25HP). I had a milling chuck from GS tooling (Sowa) and the darn collet would start to pull out and then loose its grip on the tool shank & allow the tool to come out of the collet. Then on its way back after finishing a pass it snapped off the Hanita I was testing... I tried cutting in the opposite direction to see if that would help with another tool, and still the same problem. They bragged up this milling chuck for "rouging/hogging" operations because the holder supposedly grips the tool so well that the runout is extremly low. This maybe true, but is pretty hard to machine anything when the tool works its way out of the holder. What do you recommend for a holder? Are they coming out due to such a steep helical angle on the flutes? Should I stay away from the collet style milling chucks, and just grind a flat on the tool shank & use a side lock holder? I've never used these roughing tools before so I am inexperienced with selecting the correct holder for them. Any help would be greatly appreciated. Thanks in advance!

[leggazoid]

I also had pullout problems with collets (TG 100). I had good performance with a short endmill holder with set screw on the weldon flat.

[AplusWizard]

Just tried this with the Hanita & worked great. I will have to grind a flat on the other tooling & see what happens. Thanks!

[Cmailco]

Yes, high-helix 45-60º cutters are more susceptible to pull-out due to the cutting force vectors involved.

You're using a "milling chuck" from Sowa? Is that an ER/TG collet type toolholder? Not familiar with their product lineup but in regards to roughing operations, ER/TG collet chucks have no place. If you don't want to spend the money on a good Lyndex-Nikken or Kaiser/Big-Plus milling chuck, then stick to set-screw end mill holders and tooling with weldon flats. Tool life will not be as good as what you'd achieve from a mill chuck but you don't have to worry about a tool pull-out spoiling your work or breaking the cutter.

I'd say that your particular operation; "2300 RPM & feeding at 33 IPM at 3/4" deep depth of cut" is riding a fine line on breakage either way and of course, that failure rate goes up as the tool wears.

A Lyndex-Nikken milling chuck at work in 420 stainless at 13.13 in³ material removal rate.
[nomedia="http://www.youtube.com/watch?v=XfjOCQm52Ic"]YouTube- SURFCAM Velocity TrueMill[/nomedia]