Sharpening "step type" drill bits

[Kubota-guy1911]

I'm getting to where I have a drawer full of dull step type drill bits, also known as the Uni-bit or Vari-bit. Has anyone had success re-sharpening these bits? If so, what diameter and shape of griding wheel did you use?

Thanks

kj

[GE222]

I may be wrong, but I believe that the sharpening is done with a special sized wheel which make a cut on the trough of the bit to make a new cutting edge.

[20 20]

I have a bunch also and wondered what I'll do once they become dull{some allready are}. On regular drills I just use my grinding wheel, been doing that for well over 20+yrs, never had an issue. I've thought maybe a dremel or something small might work on the step drills, but would take a looooong time.

[DanD78]

If you can find a machine shop that has an old Brown & Sharp tool grinder they should be able to do it. The cost might be more than the value of the tool. I would try using a Dremel on the back side of the cutting edge to clean up the edge. This will only work until you grind it back past the center of the cutting edge then it will start rubbing instead of cutting.

Dan

[Kays Supply]

I use a Dremel with a thin cutoff wheel to sharpen all my bits. Paddle bits, auger bits, and step.

[JB4310]

Good question, I've got 4 of them now still cutting fine, my first thought was no not practical, but maybe with a Dremel like mentioned. They must be pretty hard, and have a complex cutting edge, I doubt you would get them like new sharp.

They are the only bit I've found that can drill cast iron pipe, especially making the pilot hole, I've tried everything from cobalt to carbide, but the step drill is the only one that works, once the pilot hole is in they open the cast iron right up effortlessly.

Out of necessity I've become quite proficient at drill bit sharpening, everything from 1/8" HS to 2" carbide core bits. When my step bits get dull I'll have to give it a try.

JB.

[Kubota-guy1911]

Thanks guys for the idea's. I'll try my dremel tool or die grinder. I like these step drills in my drill press to, especially the one that can handle material up to 3/8". After lining up a precise pilot hole, drilling up to 1/2" hole is right on the money.

kev

[SPIKER]

Ive sharpened my old one several times but they usually are not quite the same. Ive been very good at hand sharpening standard drill bits and started practicing on my old step bit. It does need a different type of stone to do it very well. I chain saw sharpener might just work well if you can find a way to hold the bit steady as the angle of the cutting edge is slightly under cut I used a rounded over 4.5" metal grinding wheel on my 4.5" hand grinder that worked so so. The stone on the chain saw sharpener will work much better.

Mark

[DanD78]

Cutting oil will help extend the life of any cutting tool. In the machine shop the motto was "Always keep a cool tool"

Dan

[blacksmith]

I know Sears sells a fixture to hold router bits to sharpen them with a router and a grinding wheel with a 1/4 dia. shaft. You slide the router bit back and forth across the wheel to sharpen the back side of the router the same as the step drills. The sears model number is
25169. This is an old number but the fixture was called (Sharpening Attachment for router and shaper bits) http://www.owwm.com/pubs/222/1487.pdf Check the last page fig #7