Crazy Idea

[walterwoj]

I have a crazy idea: I have my surface grinder running no and have a stack of dull drill bits (1/8"-1") to sharpen. I lack the skill (and the willingness) to sharpen them by hand on the bench grinder, so I want to sharpen drill bits using the surface grinder. Has anyone done this? I am thinking of a simple jig to hold the bits at the right angles, anyplace I can go for more info?

 

[benmychree]

Not practical without a special fixture, a simple angle does not do it.

 

[keeena]

Cup wheel and this $10 jig? Sure.

eBay

 

[paradox_pete]

I agree it should be possible to adapt a standard drill sharpening jig, or make a jig to produce a 4 facet drill as described here.

Both approaches work just fine on a simple bench grinder too.

 

[GeneT45]

I think the four facet grind would be the way to go on the surface grinder. Stefan Gotteswinter has a good video about doing it on a single-lip cutter grinder, but it's probably all the info you'd need.

GsT

 

[OTmachine]

By four facet, are you talking about split tip? Looked it up. I usually just hand grind 59 deg. tip, (years running bar turners and screw machines where you had to keep the machine running). IMHO, not enough advantage to the split tip to warrant the setup and tooling.

 

[GeneT45]

By four facet, are you talking about split tip? Looked it up. I usually just hand grind 59 deg. tip, (years running bar turners and screw machines where you had to keep the machine running). IMHO, not enough advantage to the split tip to warrant the setup and tooling.

No, watch this:

It's a cutting edge angle and a relief angle, done for each cutting hedge - hence 4 facets. The Tormek wet grinder folks make a doo-dad to do it and they claim superior life (maybe from wet grind, keeping the drill cool) as well as less 'walk' when starting a hole. (Actually I think they say 'zero', but we all know that's not true... Stefan does split the tip on his, but it's completely optional as it is with a conventional grind.
GsT