Multiple diameter step drilled hole.

[frogier]

Hello All,

I have a job with multiple diameter step drilled holes. The material is 316L SST, there are 3 different diameter holes at the same position... Hole 1 is a .3125 diameter 6.71 deep, hole 2 is a .500 diameter 4.75 deep and hole 3 is a .625 diameter 2.75 deep... We are going to use coolant thru carbide drills in a Mori Horizontal... My question is, in what order I should drill these holes (big to small or small to big)? Any feed back would be appreciated...

Thanks

[Geof]

Big to small; carbide drills should always cut along the full length of the cutting edge.

[txcncman]

Big to small; carbide drills should always cut along the full length of the cutting edge.

+1 - Largest diameter first.