[piburners]

Im having trouble drilling this casting. so far ive tried ...
rpm from 150-300
peck .01-.1"
sfm 30-55

the drill is uncoated
the outside of my drill wears quickly or chips and burns up
also my company is under an ordering freeze so sadly i have to wait to buy a coated or cobalt
any ideas would be great

[awerby]

Some stainless steel is just not very machinable, and it all has a tendency to work-harden instantly. Using a cobalt or carbide bit can help, but failing that you could try slowing down the RPMs further, using more or better lubricant, starting with a pilot hole, and maybe using an intermediate size drill bit between the pilot and the final size.

[Superman]

Some stainless steel is just not very machinable, and it all has a tendency to work-harden instantly. Using a cobalt or carbide bit can help, but failing that you could try slowing down the RPMs further, using more or better lubricant, starting with a pilot hole, and maybe using an intermediate size drill bit between the pilot and the final size.

1+
Agreed low cutting speed with a decent cutting oil

Another thing to try is to broaden the point angle on the drill
Standard angle is 118°, harder materials is up around 130°

[piburners]

I will try and slow things down and pilot with a cobalt that i have in a smaller size. thanks

[piburners]

ive been using the 118 which is all my sharpener gives me so ill have to try and handgrind the 130. i appreciate the help