118 Vs 135 Drill Bits

[Dan_S]

Exactly, Mikey. Using my Drill Doctor 750 stops much of the squinting at small drills to see if they are correct, and is much faster as well. But when I have one bigger than 3/4" to grind, it is back to the bench grinder and drill point gage. You are also correct about the 135 degree points and splitting the points. Those are really useful and easily done on a DD like my 750.

How good is the drill doctor? I have heard so many conflicting opinions, its hard to tell.

 

[Bob Korves]

How good is the drill doctor? I have heard so many conflicting opinions, its hard to tell.

The Drill Doctor is a good machine. Like ANY drill grinder that costs less than many thousand$ (and even those as well), there is a learning curve to getting consistently good results. RTFM, practice, see how the various angles and reliefs get changed, know what you need to achieve, and it works just fine. If you open the box, throw away the instructions, slap a drill in the holder, and expect to see a perfectly sharpened drill come out, I guarantee you will be disappointed...

 

[Dan_S]

The Drill Doctor is a good machine. Like ANY drill grinder that costs less than many thousand$ (and even those as well), there is a learning curve to getting consistently good results. RTFM, practice, see how the various angles and reliefs get changed, know what you need to achieve, and it works just fine. If you open the box, throw away the instructions, slap a drill in the holder, and expect to see a perfectly sharpened drill come out, I guarantee you will be disappointed...

I wish an in between product existed, in say the $800-900 range. For a while I've been looking for something than go up to 1" that does faceted split points.

I've often thought of doing a gadget builder style one, i just could never work my head around the geometry. It seems like it would be easy now given the proliferation of electroplated CBN wheels.

http://www.gadgetbuilder.com/DrillSharp.html#Facet4

 

[Bob Korves]

I wish an in between product existed, in say the $800-900 range. For a while I've been looking for something than go up to 1" that does faceted split points.

I've often thought of doing a gadget builder style one, i just could never work my head around the geometry. It seems like it would be easy now given the proliferation of electroplated CBN wheels.

http://www.gadgetbuilder.com/DrillSharp.html#Facet4

Yes, that would be nice. The problem is that drills are not all made the same. Far from it. They have different spiral flute angles and different flute thicknesses and shapes. Just about all drill grinding schemes index the drill using the back of the flute. So, right from the start there are variable issues that must be accounted for. How else would you index a drill for grinding? I suppose you could somehow use the front of the flute, but you would still need to account for different helix angles and would still need to support the facet you are grinding. The reason you are grinding it is because the cutting portions are worn and/or damaged, and they are what you want to grind, so you can't use them. what else is there to index on that is not variable across multiple manufacturers and styles of drills?

Edit: The link you posted is a nice study on ways of grinding drills. I have read it several times, and use information from it. If people would read and understand that article before using their various grinding jigs, they would have much more success with the finished product.

 

[mikey]

How good is the drill doctor? I have heard so many conflicting opinions, its hard to tell.

Dan, the Drill Doctor works fairly well. The difference between the DD and say, a V-390 that costs over 3K, is the precision of the components. Where the DD is mostly plastic, the higher end models move more precisely. However, the drill indexes the same way - on the flutes. I recall the first time I used mine and saw the results - waay sharper than the drill was from the factory and it cut evenly on both sides; and that was a PTD drill.

You do have to read the instructions, learn to apply pressure to the wheel evenly and call Darex if you're having trouble with the machine. Once you learn to use it, it works rather well. My small drills cut very well, something I cannot always say when I sharpen on a bench grinder. I also like that I can turn a 118 into a 135 without measuring and doing the trial and error thing.

It would be nice if the DD did big drills but they don't. Luckily, sharpening big drills on a bench grinder is not as difficult to do as a small 1/8" drill is so I just do those big ones on the grinder.

Sadly, if you want the capabilities of a high end grinder, you have to pay for it.

 

[Dan_S]

what I've been thinking is take a regular bench grinder and add a electroplated CBN wheel like this one (I have it's big brother om my grinder).
http://d-waytools.com/cbn-grinding-wheels/cbn-wheel-6-x-1-1-2-x-1-arbor-hole/

then a jig like this gives you everything but a split point, and I think even that could be done given that the cbn wheel has a super sharp corner (ignore all the marketing simplicity).

You would still need a "feel" for using the tool, but a lot of variables could be set aside.

 

[mikey]

Very cool, Dan. I never knew Tormek had something like that. If you go for it, please do a review. It would be of great interest and benefit to all of us if this can be adapted to any bench grinder.

I keep vacillating on trying a CBN wheel. They should do a great job grinding HSS lathe tools for those who use a bench grinder. I don't, which is why spending over a hundred bucks to find out how well it works doesn't make sense for me but I'm still curious.

 

[Dan_S]

Very cool, Dan. I never knew Tormek had something like that. If you go for it, please do a review. It would be of great interest and benefit to all of us if this can be adapted to any bench grinder.

I'd most likely make my own, as I see a lot of flaws in that design.

I keep vacillating on trying a CBN wheel. They should do a great job grinding HSS lathe tools for those who use a bench grinder. I don't, which is why spending over a hundred bucks to find out how well it works doesn't make sense for me but I'm still curious.

I can vouch for the cbn wheels, I have an 8" on my grinder, and it eats through HSS quickly, coolly, and never needs dressed. I have a 180 grit wheel, and have been considering getting a 80 grit for the other side.

 

[mikey]

I'd most likely make my own, as I see a lot of flaws in that design.




I can vouch for the cbn wheels, I have an 8" on my grinder, and it eats through HSS quickly, coolly, and never needs dressed. I have a 180 grit wheel, and have been considering getting a 80 grit for the other side.

Keep us posted - maybe we can follow your lead!

Thanks for the feedback on the CBN wheels - I'll think on it.

 

[T Bredehoft]

Just looked up Drill Dr., smallest it will sharpen is 3/32, .094. I need to be able to sharpen .037, about one third diameter of 3/32. Guess I'll just have to continue doing them by hand.