Machining a hole in thin metal

The edges of the bit are relieved from the margin. (thin full diameter edge of each flute) the cloth wedges into this gap and centers the bit in the hole, preventing it from moving sideways in a (sometimes) 4 cornered hole, sometimes as shown. A deeper hole will allow the full diameter to enter the hole before the point exits the other side. Jim
 
Granted my machine shop days we used aluminum, but I've never had a problem drilling holes in either aluminum or steel. However, I've never used that slow of RPM either.

Still, I can understand how this could be a very useful habit to use. ...Maybe I've just been lucky in my life?

Thanks for posting this!!
 
Well anyway that is a way cool video. Only thing I do differently is use straight anti-freeze and a couple of drops now and then. Wasnt that stainless he was DRILLING? That stuff is a bear.
 
I had to make a bunch of .031 brass shims once, so I made a template out of 2 layers of 1/4 steel and sandwiched the brass in between. I had indexing pins to keep everything aligned and it worked very well.
 
If it is that fussy, I drill it smaller & ream it to size. For larger holes I have a tapered bridge reamer that works good in sheet metal.
 
As soon as I pushed the button I figured I would here from someone. I should have written circ. interp. but you can't edit.
 
Hello Patsdeere,

No..... that is not machining, but poor drilling. If both cutting side of the drill were equal the hole would ha been a lot rounder. Did not se any measurements confirming a good circle-hole. Machining is a lot more price then that. Reamer is the way to achieve much better results,

Guido.
 
(quoted from post at 16:37:50 03/10/17) Hello Patsdeere,

No..... that is not machining, but poor drilling. If both cutting side of the drill were equal the hole would ha been a lot rounder. Did not se any measurements confirming a good circle-hole. Machining is a lot more price then that. Reamer is the way to achieve much better results,

Guido.

[b:91d0fd1b51]Reamer is the way to achieve much better results[/b:91d0fd1b51]--- Or, if reamer is not available, drill finish hole removing 1/64 or 1/32.
 
Hello jeffcat,

I thought so as well. If that is the case, he was using the wrong speed among other things. There is No rednecking in machining!



Guido.
 
When I apprenticed at a GM plant they had what we called shim drills. Basically what the woodworking catalogs call brad point drills but made from HSS drills. Used them with a wood block for backing.
 
The rag and captured chips keeps the flute from catching the metal till it's so thin catching doesn't distort.
 

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