Best drillbit for steel

   / Best drillbit for steel #1  

woodlandfarms

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I am confused on all these different types if bits for steel and woos and plastic. I need to get a 5/8 hole through 3/8 steel. I kinda get the stepping up but I really don't get cobalt vs titanium vs neobonium or whatever the latest flavor is.

And who is the higher quality manufacturers?
 
   / Best drillbit for steel #2  
The last 10 or 12-years I've been buying those cheap drill bit sets from ebay, or where ever I can get them. Some of the bits have to be re-sharpened tho.:confused3:
 

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   / Best drillbit for steel #3  
Is this just "mild steel" also known as A36 or 36000 psi steel? If so, you will not need cobalt or TI bits, but they would not hurt except your pocketbook. Just regular HSS (High speed Steel) bits will work OK. A 5/8 hole in 3/8 materiel is a pretty good sized hole. I sometimes use hole saws for holes that big and bigger. What ever you use, I sure hope you have a good drill press (not some hand drill) turning at low speed with plenty of lube.
 
   / Best drillbit for steel #4  
I can't remember if you recently bought a plasma, but if you did you can cut that kind of hole with a plasma too. Just depends on how accurate you need that 5/8 hole to be.
 
   / Best drillbit for steel #5  
For a 5/8 hole in steel these days I would use an annular cutter. I think they used to be just for magnetic drills. But adapters are available so they can be held in drill presses, lathes. Some annular cutters are designed for hand held drills too. They cut fast and leave a smooth accurate hole.
 
   / Best drillbit for steel #6  
For anything over 1/2" size, I tend to use hole saws-especially if I can do it in the drill press/mill. But you need to go SLOW and use cutting oil.
 
   / Best drillbit for steel #7  
Sharp ones.
Seriously, I buy most of mine from Graingers. But I do have a larger set (up to 1") from Harbor freight. The ones with the reduced shank to use in a 1/2" drill. I recently drilled some 1" holes thru 1/2" steel starting with a 1/4" and stepping up as I went. The hardest part is once you get to the larger bits using a 500 rpm drill and the drill bit catches it will twist the drill right out of your hands. I hand sharpen all my bits sized 1/4" and up. Anything smaller I just buy new. I use high speed steel, cobalt, or titanium. Mostly cheap bits but I keep them sharpened.
 
   / Best drillbit for steel #8  
For a 5/8 hole in steel these days I would use an annular cutter. I think they used to be just for magnetic drills. But adapters are available so they can be held in drill presses, lathes. Some annular cutters are designed for hand held drills too. They cut fast and leave a smooth accurate hole.


I went this route, but only recently. Wish I had done it years ago. Drilling holes is actually enjoyable now.

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1" annular cutter with 1 1/2" cutting depth with shank adapter. (In my case MT 3)

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3/4" Rota Cut sheet metal cutter with 3/16" cutting depth. The kit comes with arbors for hand held or drill press.

Terry
 
   / Best drillbit for steel #9  
High speed steel bits for mild steel. Cobalt for stainless steel. Cobalt is very brittle and chips easily. Titanium nitride is just a coating. Works great until the coating wears off. And that doesn't take long. When the titanium nitride wears off it's just another high speed drill bit. Carbide tipped for cast iron and concrete.
 
   / Best drillbit for steel #10  
Cleveland makes the best drill bits. Not cheap but they are the best.
 
 
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