Home made drill bit jig

[Elden]

After watching the video of Jeff that Ken posted, I watched the following:

http://www.youtube.com/watch?v=-n1RccAzxLg

I think it is an interesting idea, it would be a cheap way to get a two facet drill bit. The concept sounds solid, but I haven't tried it. The cutting edge would introduced squarely to to grinding surface same as when hand grinding.

[Herman Trivilino]

That is pretty nice.  I can see how that would work ok if you have the sander.  It's not going to beat the drill doctor because it lacks the precision to control the cone angle introduced when he rotates the jig in the vertical plane.

[Elden]

Actually the cutting lip is formed when the bit first touches the grinder. Any rotation of the jig is forming the clearance behind the cutting lip. On the DBS-22, it is set at 7°, 9°, 11° or 14°. I believe on your Drill Doctor, it is accomplished as the holder is twisted.
The cutting lip contacts the abrasive in a level horizontal line. This is the same as when hand sharpening.

[Herman Trivilino]

Actually the cutting lip is formed when the bit first touches the grinder. Any rotation of the jig is forming the clearance behind the cutting lip.

Correct.  If you think of the tip as being shaped like a cone, as you rotate that jig you make the cone more pointy (smaller cone angle).

I believe on your Drill Doctor, it is accomplished as the holder is twisted.

Yes, that's correct.  By means of a cam, the cone angle changes as you rotate the bit about its axis.  For the jig shown in the video you don't get the same control over the way the cone angle changes as you rotate the bit.

Perhaps a pair of stops on that jig would help you to rotate the jig through the same angle with every pass.  That would get you closer to reproducing what the drill doctor does.

Of course none of this could ever come close to matching the precision and control it appears you get with the Tormek jig.

[Elden]

I'm not trying to say that this would be better than either the DBS-22 or the Drill Doctor. If it was, I don't imagine either one of them would have used the design that they did. Darex has proved their design over the years and has made a homeowner's version of it in the Drill Doctor. Tormek's design is great.

I would like to see side by side comparisons of bits that have been sharpened by the two machines (Darex and Tormek). The videos that I have seen of both machines have neither one shown a chip coming from both cutting lips of the drill bit at the same time. I have seen this happen with a hand sharpened bit. Did mine do it regularly, no!

I probably will make a jig just to try it out. I think it will do a fair job at a small fraction of the price of either outfit. The drill bit he was sharpening should already had the proper clearance ground on it and it appeared to be being ground from the lip to the end of the heel. No, I don't need to as I have the DBS-22, but it has my interest kicking.

[Ken S]

I agree with Elden and Herman.  In a sense, drill bits and chisels are not all that different.  In both cases, the cutting part of the edges is the very tip.  With a chisel, most of the world uses micro bevels, the ver polished quite small flat surfaces at the tip of the bevel.  With a Tormek, we can easily polish the entire bevel.  With a drill bit, whether it is ground two of four facet, it's the tip of the primary facet or just the facet which does the cutting.  the secondary bevel (clearance) just keeps the tool out of the way of the material being cut.  Brightly polished bevels beyond the micro bevel or pristinely ground secondary facets are really for show. (beyond a certain point.  They must support the cutting edge, however, there is latitude in this)

Someone mentioned sharpening bits larger than 7/8" (22 mm, hence the name DBX-22). Using the concept of the DBS-22, and borrowing some of Ionut and Herman's knife ideas, it would be easy to make a plate for the Torlock jig which would hold the bit at the 59 degree angle.  With the Torlock set at a good angle for the "primary facet", the cutting edge could easily be ground.  Grinding the clearance could be done essentially "by hand".

The concept of four facets in a drill bit works very well when the hole is drilled with just one bit.  This is certainly convenient when needed.  With a larger twist bit, especially in metal, normally a smaller center drill is used to create a pilot hole.  When used to increase the size of a pilot hole to final diameter, the four facet grind is of no advantage.  (The cutting is being done further out from the center.)

I happen to have a DBS-22.  It does a very nice job of sharpening drill bits.  The bits cut well and look nice.  I don't believe I will ever need to sharpen a twist bit larger than 7/8".  If my lathe was larger I might. With a #1 Morse head and tail stock taper, bits only go to about half an inch.

Should I ever need to sharpen larger bits, I would make a simple platform for the Torlock or scissors jig.

I find it exciting that Tormek is expanding the scope of the machine.  I find it at least equally exciting to see that scope being even larger because of clever ideas begun and developed on the forum.  Keep up the good work!!!

Ken

[Herman Trivilino]

Using the concept of the DBS-22, and borrowing some of Ionut and Herman's knife ideas, it would be easy to make a plate for the Torlock jig which would hold the bit at the 59 degree angle.  With the Torlock set at a good angle for the "primary facet", the cutting edge could easily be ground.  Grinding the clearance could be done essentially "by hand".

To grind the clearance would you have to lift the drill bit and twist it simultaneously, similar to what was done wit the jig shown in the video?

You've got my brain working on another jig, Ken!    

[Elden]

To grind the clearance would you have to lift the drill bit and twist it simultaneously, similar to what was done wit the jig shown in the video?

Actually a drill bit will function if it is ground with a flat bevel from the cutting lip to the heel if it has proper clearance. I have seen some sharpened this way and they look terrible to me. I imagine they won't hold up as well to usage.

Herman if you haven't, watch Tubalcain's drill bit videos.

When hand sharpening, the drill bit is lowered, never twisted. It will take a fairly sophisticated machine to allow twisting the drill bit, such as the Darex does. Not questioning your ability Herman as I imagine you could figure something out if you set out to! It would be easier to just swing the bit, however.

[Herman Trivilino]

Herman if you haven't, watch Tubalcain's drill bit videos.

I just now watched them, and then went back and watched the video you posted in the first message of this thread.  Both sharpening techniques look equivalent to me, tubalcain is free handing whereas the guy in your video is using a jig.  They both set the grinding angle at 59^o.  But tubalcain talks about the 12^o to 15^o clearance angle.  In essense, that 59^o angle changes to something smaller as you move away from the cutting edge, and this is what produces that clearance angle.  They both freehand this, but it might be possible to put stops on that jig to better control that clearance angle.  That's what I was trying to see.  I see now that I was wrong about the twisting of the bit, they don't do that.

Not questioning your ability Herman as I imagine you could figure something out if you set out to! It would be easier to just swing the bit, however.

Thanks Elden, but I think I'll stick just with my drill doctor for now.   

[Ken S]

I have a problem with the previously mentioned you tube.  The author's homemade jig appears to work adequately.  I have no problem with that.  What I do object to is the way he summarily dismisses the General sharpening jig.  He honestly states his complete ignorance as to how it works.  To discard it as a "POS" (his words) and discard it based on that ignorance seems unfair to me. 

I believe a fair critique should be based on an understanding of how a tool works and some experience using it.  The you tuber has neither.

Leonard Lee and Ron Hock, two experts I respect, are more kind in their evaluations of the General jig.  Neither raves about it, however, Lee refers to it as "serviceable"(p 198) and Hock states (after noting his reservations) that "it does a good job of sharpening both edges identically." (p 202)  I respect those comments.

By the way, the General jig sells for about $35, a fraction of what the Tormek jig costs. I would expect the Tormek jig to be more versatile, given the difference in cost.  It is.

I question the need to swing the bit while grinding.  Looking at a bit I sharpened on my DBS-22, the facets are all flat.  If you watch the DBS-22 video on this website, you will notice the bit is advanced in a straight line toward the stone with no swinging. (Herman) Ron Hock pictures an EZ-Sharp jig (p202) which looks like it could be screwed to either the scissors platform of the Torlock.  I think a homemade version of this could be easily put together.  The trick is to get the angles right. (not difficult)

This is the kind of homemade jig I noted in an earlier part of this post for sharpening larger bits where only one facet per side would be necessary.

With only a little practice, the DBS-22 does a pristine job of sharpening bits and will grind them to many combinations of angles.  For a Cadillac price you get a Cadillac product.  For occasional use, there are several low or no cost options.

Good sharpening!

Ken

[Herman Trivilino]

I have a problem with the previously mentioned you tube.  The author's homemade jig appears to work adequately.  I have no problem with that.  What I do object to is the way he summarily dismisses the General sharpening jig.  He honestly states his complete ignorance as to how it works.  To discard it as a "POS" (his words) and discard it based on that ignorance seems unfair to me. 

I thought the same thing.  And then in Tubalcaine's three-part Youtube series on drill bits he actually hits what looks like exactly the same jig with a hammer before he tosses it in the trash.  He free hands his on a belt sander.

I question the need to swing the bit while grinding.  Looking at a bit I sharpened on my DBS-22, the facets are all flat.

Huhh? Aren't the secondary facets conical?  Come to think of it I guess maybe they don't have to be.

Anyway, if the guy in the Youtube video didn't swing the bit how would he get a clearance angle?  He's not doing the four-facet method.

(Herman) Ron Hock pictures an EZ-Sharp jig (p202) which looks like it could be screwed to either the scissors platform of the Torlock.  I think a homemade version of this could be easily put together.  The trick is to get the angles right. (not difficult)

I agree, Ken.

[Elden]

I actually have a General jig sitting in the shop. It has been years since it was used. Contrary to what the one fellow thought, I don't remember it being that difficult to set up. I believe it had an index for holding the cutting lip in position. On the wooden jig, that is controlled by the operator. It is a matter of lining the cutting lip with the grinding wheel, similar to lining the cutting lip up with the line on the DBS-22 holder.

As far as Tubalcain's view, I agree that once a person becomes proficient at hand sharpening, that the General or the wooden jig would be unnecessary. To him, it is a simple matter of walking up to his sander, turning it on, and a few moments later walking away with a sharp bit.

One fellow I used to work for, did split points by hand well. He had a Darex grinder (not a Drill Doctor version), that he did not use for drill bits. He used the diamond wheel on it only for sharpening the cutting tools for the metal lathe. I never did get sharpening split points by hand accomplished.

In my situation it has become difficult to be able to control the sharpening process as I used to. I still have to figure out if using the DBS-22 is going to be workable from my seated position. I trust it will as I like the idea of the four facet bit.

[Herman Trivilino]

With only a little practice, the DBS-22 does a pristine job of sharpening bits and will grind them to many combinations of angles.  For a Cadillac price you get a Cadillac product.  For occasional use, there are several low or no cost options.

All this talk about drill bits, plus having all the thoughts from Ron Hock's book swirling through my head, has gotten me to take another look at the DBS-22.  I watched the video on the Tormek site and also the video on the Sharp Tools USA site.

It's got me drooling.

I can now better understand the primary and secondary facets, and the relief angle.  I know Christmas is a long ways away, but I think I'm gonna sharpen my pencil for that letter to Santa.

[Ken S]

Herman, I'll stand by my last quote.  You do get a Cadillac tool for a Cadillac price.  I've never owned or wanted to own a Cadillac.  I'm more comfortable in a humble Chevy.  However, I do like the Cadillac DBS-22.  I truly believe anyone on this forum could learn how to sharpen drill bits with a grinder and no jig.  The question is how many of us would take the time to learn the skill.Even the argument about conserving one's precious tools doesn't really hold water.  how many eight dollar drill bits would be required to become proficient in hand sharpening?  I would think that by the third bit most of us would be reasonably proficient.

The humble General jig would doubtless be more than adequate given the operator skill to use it well.

So would the Drill Doctor.

So, why the DBS-22?  With practice, it will do pristine four facet sharpening.  After all, if we really wanted to go with the low bid, why would we be on the Tormek forum?

Herman, my suggestion would be to talk with your local Tormek dealer and see of any woodworking shows are scheduled for between now and Christmas.  Often the Tormek and accessories are available at  20% discount, something any Santa's helper would appreciate. 

Ken

[Herman Trivilino]

Thanks, Ken, I'll look into that!