MetalworkingFun Forum

Hi

I know that in the engineering company that I work for some drills are ground to 90 degrees to use for contersinking holes as most countersunk pins are 90 degrees. Most of the countersunk rivets ( pop rivet type) are at 120 degrees and sometimes drills are ground to suit - usually smaller drills up to about 8.00 mm. We sometimes get drawings with different angles for countersinks I have seen 80 degrees asked for but I`m not sure what fasteners are at that angle.
I`m not sure how different the drills are ( other than the angle of course) from a normal 118 - 135 type - maybe Tom could give us some guidlines/video for countersink drills?

Cheers

Paul

(09-02-2013, 11:27 AM)oldgoaly Wrote: [ -> ]Just prove I'm not seeing things....


not well organized, just box in a drawer, and another drawer, plus the sets of drill we use, plus a box in drawer in the barn.

Using the angled portion of that gauge should give you drill bits with 118 degree tips.

Ed

I got myself confused, I've got a couple of M.A.Ford chamfering bits so never thought for a bevel head screw a spotting bit, Familiar with the term spot face, most of my countersinking has been counterboring bits, so spent some quality sorting that old box of bits, found a whole bunch more spotting bits! even 2 yankee push drill bits. Are we having fun yet?

Hi
Tom
Nice video well shown & explained

John