Reaming out holes in thick steel?

[IndyJay]

I like this TBN forum. Lots of good input, not much b.s., most of the time.

It is a great forum, even the BS is good some of the time...

 

[bjr]

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?

pneumatic die grinder with a diamond cut bit would take care of it as well. Just be aware it will probably want run around in circles in the hole so go slowly.

 

[ROUSTABOUT]

Use a torch or a die grinder. Be done in a few minutes. Pick one up at a pawn shop. You're welcome.

 

[the old grind]

So many good options/aspects mentioned here. If grinding or filing I might trace a target outline to rough the opening. Holding any power tool steady/firmly is paramount. Lube oils are poor cutting fluids unless 'hogging' and 'flooded'. Use bacon grease or pork drippings liberally with power tools in a pinch. Your chip will always tell you if you're going slow enough, using enough pressure, and/or cutting efficiently w/o dulling the tool before you're finished.

My top choices are a bridge reamer, step bit to its max OD & w/coolant, or piloting/stacking hole saws. If you break the corners of a conventional drill bit do so sparingly. IMO, metal is likely low carbon steel and wouldn't work-harden. btw, if you get 2-4 holes before your cutter is toast you did good. It's being hand work that makes it so.

 

[Sberry]

Good point about the work hardening.

 

[flagman12ron]

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?

a pointed burr should be helpful and you can use it with a lessor powered drill so if it catches you won't get hurt good luck ron