Drilling Iron

Ah... got it.

Jamie

Dan Caster wrote: (clip) Sometimes I drill the pilot hole almost all the way thru and then fill that hole with oil before drilling the full sized hole if I am drilling thick material. (clip) ^^^^^^^^^^^^^ That's a good idea!

Noted. ;-)

I did start to say something about enough power and rigid enough machine, but considered that he was using a hand held drill. So did not mention table flexing. But that said, I almost never use more than a pilot hole and the final size on holes less than 1/2 inch dia.

Dan

Here's a good page of description of all parts of a twist drill:

-- --Pete "Peter W. Meek"

Here's what I learned as I drilled:

I used one jig of my own design: I slotted (1/2 deep) a piece of 3/4" ply on the table saw, exactly the width of the steel I was drilling. Once I had a satisfactorily centered 1/16" pilot hole in one piece of steel, I put a stop block in the end of the wood slot, and laid an undrilled piece in the bottom of the slot. I butted it against the stop block, and laid my "template" (well centered hole) piece on top. I put my hand drill in a cheesy B&D device which "turns your hand drill into a drill press" (I had it laying around the garage), and drilled through the template into the new workpiece. This was a big success and a great leap in precision, compared to past projects, for which I measured each piece before cutting, and attempted to center each hole (unsuccessfully).

Also, as suggested, I applied cutting oil to the bits as needed with an acid brush.

I did, however, manage to break a lot of thin pilot bits, since when I pulled the handle of the "hand-drill press" the bit travelled a lot (laterally) during the pull.

Now, onto countersinking: This seemed to require much more pressure to get shavings than did boring, and I stripped the lever gear on the "hand-drill press" on the second countersink (of ~100). The rest of the countersinking went terribly slowly (hand-holding the drill), but I didn't dull the bit this time, thanks to a lot of cutting oil, and I frequent dipping of the bit into water (to cool it).

Once I broke the chintzy drill fixture, I did a lot of hand-holding of the work against a wood block, and really tore up my hands and wrists, applying all that pressure. Also, for the next few days, I gained an appreciation for the level of aggravation caused by dozens of hair-like steel splinters in my hands.

Anyway, despite the (minor) setbacks, this project went a lot better than it did last time, thanks to r.c.m.

Thanks again, Jamie