How to Hand Sharpen a Twist Drill

[TomG]

(12-17-2012, 08:40 AM)Mayhem Wrote: I must be honest and say that I didn't actually watch the video until now, as I was in a rush earlier and (wrongly) assumed it was a link to one of the ubiquitous drill sharpening videos on YouTube. Then I heard a familiar voice and gave the vide due course and attention.

The main issue I have is setting the initial angle on the cutting edge. The back relief isn't a problem but I sometimes wonder how much angle to place on the cutting edge. I roll away from the cutting edge to create the back relief but I may try your method as well.

Thanks for making the video Tom.

Thanks Darren.

The angle of the point is basically related to the hardness of the material to be cut. Choose a flatter point (135º) for tool steels and stainless and a steeper point for softer materials like mild steel and non ferrous metals. The trade offs are that while a flatter point will dissipate heat more readily it will also be more apt to wander. By the same token, a steeper point will self center, but wear more quickly.

I opted to do the faceted clearance angle just to keep things simple and basic. The rolled back relief is the norm, but takes more skill to get it right.

Tom