Dull dril bits

[hardtimes]

Originally Posted by just plain bill

This may come as a surprise to some of the people that have posted replies on this thread. You do sharpen a drill for brass a little differently. While you need proper clearance at the cutting edge you also grind or stone a slight neutral flat on the face of the cutting edge. Notice I said neutral not negative. Other wise the drill will screw itself into the brass. I do agree that it would be easier in the case of brake shoe rivets to use a punch to remove them. I learned how to sharpen drills in 1958 when I went to work in an automatic screw machine shop. I believe that I have sharpened more drills by accident than most machinist do on purpose. LOL

Hey Bill,
I hear you , relative to the 'neutral' zone
As a youngster, I worked building C130 Hercules for 5/6 years. During that time, I can say that I USED UP and broke more drills than most machinist and others have ever handled/seen in a lifetime. I'm talking aircraft quality drills that , back then, most would never even see/handle.
However, never sharpened one nor even wondered about where that endless supply came from...tool crib ? No body ever came close to my putting out both center wing beams from two gantries ..in two days each , however it cost them a LOT of drills, for which they never complained !!

[George D]

I think the rivits are spinning

[Spokes]

Originally Posted by mshmodela

Sounds like this type of bit...

Good one !!! Sometimes I am using that same drill !!!

[Tom Wesenberg]

Originally Posted by George D

I think the rivits are spinning

Good thought because they always spin for me. I have to attack them at an angle and push hard to get them just ready to pop, then I use a punch to finish them off.

[silversink]

all I have are dull bits and duller after I try to sharpen them

[just plain bill]

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As A drill gets dull the margins wear, Margins being the outside edge. To properly sharpen the drill it must be cut or ground back far enough to give or have a full margin. As the margin wears the drill rubs more and just creates more heat and requires more pressure to cut through the material. Years ago when i worked at a large aircraft manufacturer they scrapped dull drills smaller than 1/4" as it was cheaper to buy a good replacement than to sharpen them. I personally prefer the split point grind because with a standard grind the point is chiseling its way through. They cut good enough for the home project. I can't begin to tell you what we sometimes had to do make a drill cut efficiently.