Inner sactum oil galley plug

toolmanmike said

Well, I should delete my post because what I said obviously doesn't apply to engine manufacturing. At least not by today's manufacturing procedures. Heck, back when I was operating the automatic screw machines we still used braised carbide tooling. As far as I know the blocks were step drilled the same way back then.

Click to expand...

I,ve been a tool and cutter grinder for 29 years. We used to use brazed carbide step drills too. Now it is all indexable throw away.
But the process has always been step drill. As you said at least in the auto industry. I cannot speak for other industries. We have drills that are probably 18 long to drill the oil galleys for your lifter bores all drilled in one shot. These bean counters look for any way possible to reduce cycle time. Sorry I was not trying to dis you, just trying to share info. I sharpen probably 50-100 step drills a week an dreamers too.