Reaming out holes in thick steel?

   / Reaming out holes in thick steel? #61  
I would try a set of titanium coated step drills. Available at TSC harbor freight or. Lowes
 
   / Reaming out holes in thick steel? #62  
Get a device called a “Tapered Bridge Reamer” with a 1/2” shank. They work exceedingly well and leave a pretty nice finished hole.
They come in various sizes, but you will need a 7/8”, and the smaller diameter might be in the 11/16” range, or thereabouts.
Should cost less than $100, but in a lifetime of doing this kind of stuff, it’s the best way I have found.
 
   / Reaming out holes in thick steel? #63  
I recently did this with a router and a carbide burr. I slowed the router speed down a bit and just kept going around the hole and test fitting, worked perfect.
 
   / Reaming out holes in thick steel? #64  
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?
Turning your problem on its head, could you machine the pins to fit the existing holes? Lots of folks have small lathes that I'm sure would help you out.
 
   / Reaming out holes in thick steel? #65  
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?
Try a unibit from harbor freight. About the cheapest way out I can thing of.
 
   / Reaming out holes in thick steel? #66  

I have had good luck with a high quality step bit that I found on Amazon. I don’t recall for sure but I think it was around 10 bucks
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?
 
   / Reaming out holes in thick steel? #67  
Take a block of wood and drill a hole with the size bid you want it to be. Fasten the block of wood solidly to the piece you want to drill out and then use the wood to hold the hole saw concentric to the hole and have fun.
 
   / Reaming out holes in thick steel? #68  
A few items:

1) if you have or can borrow one you should use a good 'ol fashion 120vac 1/2 drill- the large body style. Hopefully it has a place for a 2nd hand hold. These drills are geared down and only run a few hundred RPM.

2) Cutting oil. Even some old drain oil is better than nothing.

3) Your drill bit needs to BE SHARP and kept that way. I hope you can hand shape a drill bit. If it was me I would 'break' the cutting edge esp since you are boring out an existing hole. In other words you are changing the angle of the cutting edge so it doesn't plunge when drilling or breaking though. Use a knife sharpening stone. Looking at the twist of the flute, eyeball the stone to be just off of parallel with the length of the bit and make both sides the same.
 
   / Reaming out holes in thick steel? #69  
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?
So why not just leave them 13/16. You won’t be gaining any extra strength by boring them to 7/8.
 
   / Reaming out holes in thick steel? #70  
A holesaw works well for changing hole diameters/alignments. Go slow, use lots of oil. A predrilled board clamped to the work makes a decent guide. I have had to do many in-situ metric-sae conversions this way.
 
 
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