Allied GEN2 T-A

[AplusWizard]

Hi all, I hope some one with experience with the Allied Machine line of spade drills can help. I have blown two spade drills while drilling a 3/4" dia hole 6" deep. The body has twisted flutes and is about 11" long and has an adapter off the side of it to provide coolent down at the tip of the drill. The spade is the HSS super cobalt has the AM200 coating. The material is 1018 steel, and we are using a Challenger 50HP vertical mill with a 4th axis. Their literature says to use a SFM of about 350 fpm, and a feed of 0.013 ipr. This seems extremely excessive, and like I said I've toasted two of these things already, and I'm not even close to their parameters (1020 rpm and 0.0059 ipr). Should I stop being a pansy and go with their figures? I hope someone can help. Thanks in advance.

[BSawyer486]

I have seen alot of typos in there recommendations for SFM I would check their website and see how it compares to the print info. I use alot of spade drill and that is way high. probably more like 180 SFM but the chip load sounds a little heavy, more like .009 per rev.

Bruce

[WOLOG]

What is your coolant pressure? Is the coolant coming out of the standard pump? I would say that 350 SFM is high. The other thing is that the drill is probably an extended flute which needs to be slowed down a touch. I have a 1000 psi pump on my mill and it makes a world of difference with spades.

[davereagan]

Are you drilling a starter hole? How does it fail? All the way in? Are the chips jammed up? 350sfm is definitely too high. The highest I've ever seen non carbide spade drill inserts spec'd at is 260sfm and that's with TiALN coating, not TiCN or TiN, but you are only running 200 sfm anyway.