O/T 0.5mm drill in S.S

[DavidB]

Hi all,

I need to drill Diameter 0.5mm x 4mm deep in 15-5ph S.S

Would you use HSS cobalt coated or Carbide?

I can get either and the price of the carbide is only $5 more I need to drill 65 holes.

 

Thanks in advance

[crazy^millman]

Would look to a cobalt with a good coating if it were me. Might have luk with Carbide but need a good holder and a small peck in 15-5.

 

HTH

[DavidB]

Crazy,

What would you call a small peck 1/2 x D?

[DavidB]

Bump

[Harryman]

I run small carbide drills in an air spindle at around 24000 rpm and feed about .00003" per flute and peck about .003" in 304 stainless.

 

Coolant access is a big deal. An ER16 collet will sling /block coolant and leave the tool dry.

 

I have good luck with .04" drills in a slender shrinker at 12000 rpm.

 

It's hard to specify the size of flutes on circuit board drills, but use the stiffest ones you can find. Some I've tried had a very roomy flute and the lack of tortional stiffness caused unpredicable life.

 

Mitsubishi makes some very nice small drills but they are very expensive.

[DavidB]

Ive only got 7000 rpm going to use a ER8 collet.

Peck 0.1mm depth with feed 19mm min?

Thx