Reaming out holes in thick steel?

[FatTire]

I want to enlarge four 13/16" holes in 1/2" thick steel to accept 7/8" pins. This on a piece of equipment so I have to use a hand drill. I happened to have a 15/16" black oxide bit, not too surprisingly that doesn't work at all. In 10 minutes I only penetrated about 1/8" in one hole. So I need to decide between buying an $80 construction reamer (high speed steel, manufacturer says it is OK for stainless) or pick up a 29/32" cobalt drill for under $50. I'm guessing the reamer would work better even though it is softer. Is that correct?

 

[jmc]

Cobalt drills are harder than high speed steel, but brittle, and tend to chip if setups are shaky, like with hand held drilling. HSS reamer might work better, if you're not taking too much out. I'd finish the hole you started on last, in case it's been work hardened.

Did you resharpen your 15/16?

 

[mrmikey]

Reamer would be lot better, using a bitt you're going to either break it, break your wrist, burn out your drill or jamb your fingers. Get a three flute tapered reamer. If you're not fussy about being perfectly true, use a carbide burr..........Mike

 

[FatTire]

Thanks. The 15/16 was basically new, I used it for one project drilling some thin aluminum, just a couple of holes.

 

[5030]

Did you resharpen your 15/16?

The question is...do you know how to correctly sharpen it?

 

[FatTire]

Reamer would be lot better, using a bitt you're going to either break it, break your wrist, burn out your drill or jamb your fingers. Get a three flute tapered reamer. If you're not fussy about being perfectly true, use a carbide burr..........Mike

On my first attempt I thought my wrist would be wrecked a few seconds before the drill burned out.

 

[workinonit]

That's a tricky thing to do when you can't vise it down in a drill press. Any chance you can use bushings instead? I'm not sure of your application but I think I know what you are trying to do.

 

[workinonit]

On my first attempt I thought my wrist would be wrecked a few seconds before the drill burned out.

Are you using an AC drill or battery powered?

 

[zzvyb6]

I'd use my fire wrench with a washer template on both sides. If these are for lift link pins, don't they have a shoulder on them to hide your artwork ?

 

[workinonit]

It's amazing what a good cut I can get with my plasma cutter with a guide template. Problem is, you have to have a plasma machine.