Reaming out holes in thick steel?

   / Reaming out holes in thick steel? #81  
How do you stay true center with the hole saw w/o use of a pilot hole? I remember somebody on youtube showing a neat trick for that, but don't recall exactly what he did.
Easiest way I've ever done consisted of a scrap piece of 3/4 ply or a 1x that covered the existing hole and was clamped in place. Do your best to drill a pilot hole in the center in the existing hole through the ply (I've used a holesaw that was just a bit smaller than the existing hole to get my center). Put the correct sized holesaw on your drill and use the pilot hole you just made to start the hole in the ply. After you get a 1/16-1/8 inch in the metal you can remove the wood - the holesaw will stay in the newly cut "hole ring". Hope this makes sense.
 
   / Reaming out holes in thick steel? #82  
Try a unibit from harbor freight. About the cheapest way out I can thing of.

Quickest, easiest way to do this. Get a 7/8” max OD step bit.

I recently enlarged a 1” hole hitch ball mount shank to 1-1/8” to fit a Cat II hitch pin this same way. Took a whole 3 minutes to do.
 
   / Reaming out holes in thick steel? #83  
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?
The bits we use are called “nitro” drill bits and they will chew through that steel like butter. A 7/8” is probably $15. Black and gold in color. Get them at a specialty fastener place.
 
   / Reaming out holes in thick steel? #84  
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.
Funny I suggested the on first page and was completely ignored.... If one learns to work with a reamer they will never use a twist drill or hole saw or carbide burr or abrasive wheel again.... Had to do about 16 holes in 1/4 inch plate, to 7/8 inch and after all said and done reamer was still pristine and no wrenched wrist or arm from 120V corded drill.... Just dont try it in a "torch" cut hole because it will grab and destroy the cutting edges....
 
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   / Reaming out holes in thick steel? #85  
you say you want a 7/8" pin but are using a 15/16 drill???? Slop in those kind of holes lead to very little bearing surface and rapid wear. Find someone with the proper equipment and knowledge.
 
   / Reaming out holes in thick steel? #86  
ok, I'm not sure how well this will work, but it is a cheap option. I just used one of these to drill 168 holes in tube steel, and it worked very well. It might work on your 1/2 inch plate. Black Oxide Step Drill Bit Set, 2 Pc.
 
   / Reaming out holes in thick steel? #87  
I havnt used the black but have the titty ones and cant tell the difference with them vs the brand ones. I have heavy duty drills, abused them and then some. Cant tell they are not new.
 
   / Reaming out holes in thick steel? #88  
I am floored that with a quick glance at every page of this thread no one has mentioned cutting fluid. o_O

Every one of you should have and be using lubricant when drilling metal unless you simple don't care about roasting bits all day. 13/16 to 15/16 is virtually nothing with the proper drill bit, rpms and cutting fluid. A step throw away 7/8 step bit with fluid would cut those holes in about 5 seconds.

 
   / Reaming out holes in thick steel? #90  
I am floored that with a quick glance at every page of this thread no one has mentioned cutting fluid. o_O

Every one of you should have and be using lubricant when drilling metal unless you simple don't care about roasting bits all day. 13/16 to 15/16 is virtually nothing with the proper drill bit, rpms and cutting fluid. A step throw away 7/8 step bit with fluid would cut those holes in about 5 seconds.


Actually, the use of coolant was mentioned in several posts.
 
 
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