17-4 in condition A can be a little unpredictable. No were near as bad as 304,
but it can vary a bit.. And it still has its sticky stainlessy properties.
Again not as bad as 304... Nothing sucks more than 304...
One thing I have found in workhardening stainless.. You have to be careful with
your pecks.. That chip is nasty, and if you rapid out of the hole without
cutting the chip off first, you can rip the cutting edges off of the drill...
Generally pretty easy to add a dwell (But don't let it rub of course
).. I longhand it when
I have to, feed back out .020" or so, then rapid, or fast feed back in to the same
point..
If I'm only doing a couple holes, I'll just turn the rapids way way down.
Another thought.. Stainlessy stainlesses can be nasty when you break out the back side.
Sometimes its productive to make sure everything is nice and cool down at the bottom
before breaking through, you may have damaged the drill on the through holes...
Another random though.. Speedio.. Are you out of the hole long enough to get coolant
into the hole before it goes back in.. Another little thing I do when I long hand my
drill cycles.. Not always, depends, I'll come up quite a bit further than my clearance
plane to make sure I get a new batch of coolant down into the bottom, and it also
leaves a bit more room for any chips on the drill to go away...
Quick story.. Lathe, and not stainless. 1-5/16" drill in 4140 I think it was.. Going
almost a foot deep.. Just a twisty drill, it was only 40 parts.. If I ran full
rapids, the bottom of the hole and the end of the drill would melt down.. If I ran
25% rapids, everything came out great.. Of course a well meaning employee saw the
rapids turned down, and turned them up and I ended up with a melted drill...