Problems with 316 stainless

[Thee Dragracer1951]

I have a job where I need to put 60 3/4 holes that will be bored to .770 in 316 stainless. This is plate 3/4 thick nad I am going through. I have faced both sides.

I have an inserted 3/4 spade drill and am blowing up inserts.

I have tried everything from 40 to 100 sfm and .003 to .01 for feeds. Just called the tech rep from the insert mfg and he told me 64sfm and .0064 per rev with .03 pecks.

I had not been pecking for fear of work hardening it...

What think you?

This job is just kicking my butt

[chowquoe^]

I'd try his suggestion, but ask him if he is going to buy the busted inserts. I would also ask him if he wants you to G82 or G83, I know I actually had a drill rep that wanted us to chip break.

 

[Thee Dragracer1951]

Who woulda thunk it???

The tool guy actually hit it on the money...

Can ya hear that little machine just chuggin along?

I can...

[Lars Christensen]

I am not a expert, so my suggestion would be on your own risk, but I would run a HSS Spade drill in 316 at 45sfm at .006 ipr, it is carbide I would run it at 145 sfm at .01 ipr.

 

Please let us know how you make out

[Lars Christensen]

ok, well disregret my post

Glad you got it running, and I can hearit, sounds mighty fine

[gcode]

Ingersoll Qwick Twist Drills

are amazing. They are ment to be used with

thru spindle coolant, but you're drilling shallow holes so you should be OK.

They are not cheap but they work.

I recently drilled a .375 hole 3" deep in 321SS

with one of these. 25 parts with 2 holes per part with 1 drill tip.

The first hole looked as good as the last.

 

edit:

3/4 QwickTwist in 316 SS

middle of the road feeds and speeds for this cut are

585 rpm and 4.7 ipm and no pecking

 

You didn't mention whether you were spot drilling the holes. If you're using a short body, you shouldn't need to. Igf you are spot drilling make sure to use the same point angle for the spot as you do for the drill. A 60° center drill hole

will chip the cutting edges of a spade drill

 

[ 12-29-2006, 08:42 PM: Message edited by: gcode ]