"Drilling" a 2 1/2" Hole ???

If you have a milling machine of any type, and a 1/4" carbide side mill... Mark the center and a spot at the desired radius. Drill the center mark with a 1/2" bit. Place a 1/2" stove bolt through the hole and clamp in the mill vise on the bolt shaft so radius mark is off the end of the vise by 3/8". Position the vise so the radius mark is under the milling bit. Lower the bit to cut through the plate, and then slowly rotate the metal to cut the circle. Coolant flooding makes this much smoother.
 
A bi metal saw will work if you go slow and use plenty of oil. I would use a torch myself and clean it up with a round stone on a 4 1/2 grinder. To torch it, center punch your hole, then use a compass to scribe the circle. Then make a bunch of punch marks around the scribe line. Blow through with the torch well inside the line move to the line and go slow. If you need to reposition kick the cut to the inside a bit and come out. Reposition and start from where you kicked in. But then, I have cut a lot of holes with a torch.
 
Drilling the circle of small holes and cleaning out isn't really as hard as it sounds. You can always insert a jewelers saw or hack so to connect the dots if you drill a large enough hole. This method doesn't require buying any thing at-least. I can't help but think you won't get much life out of a bi-metal hole saw, although I can't comment on the above "adjustable hole cutter".

Not having a mill at home, that's how I'm skeletonizing tangs currently. The hard way ;) Been working fine, if slightly labor intensive for upto 1/4" steel.
 
fluidsteel said:
I could be wrong, but I don't think that will cut more than sheet steel? I have one similar with a mill type bit for cutting holes in duct work etc.
Click to expand...

Lol We routinely bore holes in 1/4"+ plate stock using a similar tool. Why wouldnt you think it would cut thicker stock? the cutter is very similar to a lathe bit, and as long as you can feed it, it will cut.
Jason
 
JasonSCarter said:
Lol We routinely bore holes in 1/4"+ plate stock using a similar tool. Why wouldnt you think it would cut thicker stock? the cutter is very similar to a lathe bit, and as long as you can feed it, it will cut.
Jason
Click to expand...
Because I went to the site. And it said this....
The Adjustable Hole Cutter is designed for cutting 1” to 6” holes and discs in sheet metal, copper, brass,
aluminum, plastic, wood and composition materials. Maximum 3/4” cutting depth. Reverse double-ended
cutting blade to change from circle to wheel cutting. Used by woodworkers, hobbyists, model builders,
clockmakers etc... Supplied with hex wrench, cutting bit and pilot hole drill. Use in any drill press or drill stand

I haven't used that tool myself, and am a plumber, not a machinest. I apologize if that came across as argumentative and not questioning like I intended.
Rereading the specs, it still sounds like it's for thin sheet metal and softer metals up to 3/4"?
 
lol I apologize as well, if any slight was taken. i didnt mean it to be. Haveing personal experiance with this type of tool, I know it will cut plate steel up to atleast 1/2" thick. if fed slowly. Your speeds and feeds is where it's at. as always YMMV, though. :)

Jason
 
JasonSCarter said:
lol I apologize as well, if any slight was taken. i didnt mean it to be. Haveing personal experiance with this type of tool, I know it will cut plate steel up to atleast 1/2" thick. if fed slowly. Your speeds and feeds is where it's at. as always YMMV, though. :)

Jason
Click to expand...
Cool!

Thanks, always good to add to my knowledge base.
 
You must log in or register to reply here.
Back
Top