Drilling stainless steel question

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Dad

New Member
Nov 29, 2019
7
PA
What's the easiest way to drill 1/8 in holes through a stainless steel rain cap, top plate (vertical portion) & liner.
I must be doing something very wrong. I'm using a new DeWalt cobalt bit, going slow and keeping everything cool... and this is taking forever.
 

begreen

Mooderator
Staff member
Nov 18, 2005
90,490
South Puget Sound, WA
Centerpunch to start. Use a cobalt bit with a 135º point angle that has a titanium carbonitride coated tip. Put a drop of oil on the tip before each hole.
 

Bad LP

Minister of Fire
Nov 28, 2014
1,782
Northern Maine
Problem with stainless steel is some grades can be work hardened. Once that happens you’re screwed.
Easy pressure. Slower turning speed. Lots of cutting oil. The oil needs to be on the drill points. A drop at the start with nothing during the process is absolutely useless.
 
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semipro

Minister of Fire
Jan 12, 2009
4,077
SW Virginia
A drop at the start with nothing during the process is absolutely useless.
Why is that?
I've been bad about using oil and wonder about the benefits.
 

Bad LP

Minister of Fire
Nov 28, 2014
1,782
Northern Maine
Why is that?
I've been bad about using oil and wonder about the benefits.
cutting oil cools and provides lubrication to the cutting edge. Understanding feeds and speeds helps a great deal.

I can drill something like a mad man once or I can work till coffee break with the same cutting tool treated properly. The tougher the working materials the more important it becomes.
 
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