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Black Diamond Drill Grinder

Ron of Va

Aluminum
Joined
Jul 19, 2008
Location
Tidewater, Va
I thought I would share some photos of my Black Diamond Drill Bit Grinder that I bought a while back. Model 1B. It was made in the 1940’s according to the guy at the Black Diamond web site. It was kind of dirty so I did some cleanup. I have read where some people feel the Black Diamond is the “Cadillac” of drill bit sharpeners.
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This drill bit sharpener uses a single collet for each size drill bit from #70 to an 11/32”.
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First the drill bit is inserted into the collet holder. At that time the depth and angle can be set by inserting the collet holder into the drill bit “locator” on top of the machine and tightening the bit in the collet. There is a different locator for different groups of bits from smallest to largest.
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I could not find any information on how to properly set the depth stop or the angle of the locator pin, so I winged it. I used some parallels with a piece of masking tape to set the distance to what would be the grinding wheel. All depths were set off the same position of the grinding wheel using a representative drill bit for each locator. I just scraped the tape as I didn’t want to use a stone for this job.

I also used a 25 degree angle block to set the angle of the locator pin.
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The machine has a nice split point feature. It came with a factory spacer that is used to change the rotation of the bit in the holder so it can approach the grinding wheel in the proper orientation. I found that using this tool left too much of the bit sticking out of the end of the collet which caused the grinding wheel to split the point too far down the shaft of the bit. So I made a split point spacer that keeps the bit down further in the collet. This lets the bit just be split at the top of the bit and not too far down on the shaft. I like it much better.

The split point bit on the right was one done at the factory, and the one on the left was one done on the Black Diamond, with the homemade spacer. Once set, just turn the holder 180 degrees and split the other side of the bit.
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I was a little disappointed that the capacity of this machine was 11/32. So I made a homemade “wing cam” collet holder to sharpen larger drill bits. It holds the bits in an acetal split collet in the back and uses a bushing in the front to keep the bit centered.
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This machine has a built in diamond wheel dresser for the side of the grinding wheel. But in this early model there was no front edge dresser, mounted on the back of the machine. So I mounted a square guide in the hole where the split point attachment is mounted, and use my diamond wheel dresser that I use for my other grinders.
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I also cut out a 1/16 sheet of neoprene that covers the base of the machine so the grinding dust doesn’t stick or accumulate on the machine. Just blow or vacuum it off.

This machine sharpens drill bits better than new, especially the really tiny ones. I can’t test it past #60, because I don’t have any bits that small, nor do I have any collets that small.
 
I used to use one of those at a plant I worked at. Real handy. We used a lot of 1/8th inch bits, and dulled and broke off a lot of them in the process.

I got to where I could free hand those size bits and get them real accurate to where they'd send up twin spiral chips as they were cutting.

Now, I can't see as well as I used to and would have a hard time doing it!
 
Ron, Can you possibly post the dimensions (at least the thickness) of your spacer and the factory spacer? I think the factory spacer is more for "web thinning". Your thinner spacer allows point splitting. This appears to be a model 1B. If anyone has the spacing attachemeng for the model 2B, I'd love to have the measurements for that (or, if you don't want it, I'd be happy to take it off your hands - please PM me).

Your periphery dresser, and your neoprene ideas are great. Thanks for a very helpful post!
 
Ron, Can you possibly post the dimensions (at least the thickness) of your spacer and the factory spacer? I think the factory spacer is more for "web thinning". Your thinner spacer allows point splitting. This appears to be a model 1B. If anyone has the spacing attachemeng for the model 2B, I'd love to have the measurements for that (or, if you don't want it, I'd be happy to take it off your hands - please PM me).

Your periphery dresser, and your neoprene ideas are great. Thanks for a very helpful post!

Yes, Please!!

I have a similar grinder, and the point-splitting spacer and perhaps some other parts are long since missing. It does a great job sharpening, however. I needed to rebuild the diamond dresser holder.

If you can post a drawing of your part, that would be very useful.
 
The spacer is not a “precision” part; it was made from a 1/8” thick piece of scrap flat stock. I am not sure how to describe the dimensions, but here is a photo of it on a ¼” graph paper. The factory spacer is .500”.

It was made on a rotary table to get the hook after first drilling the center hole. The critical part, and the last thing that is cut, is the location of the notch on the bottom that locks it in place and locates the rotation of the hook.

I installed the homemade tool on the wing cam, located the hook on the locator pin where I wanted it, and with a felt pen, I marked the location and the depth of the notch on the homemade tool. Since the pin is ¼”, I used a ¼” endmill to cut the notch. It does not have to be perfect, because there is a fine rotation screw to make adjustments.

I hope this helps.

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Thanks again. If I am interpreting this right, the factory spacer would be good for web-thinning (two little notches centered in the bottom of the flutes), while your thinner spacer allow you to tip the drill more and get an actual split point. Very clever idea, and it really amps up the versatility of the grinder!.

Jim
 
Jim,
The web thinning instructions about the spacer that I have, provide very little detail. As you can see in the photo the factory spacer has two holes and a groove. So the spacer will fit over the main collet holder in two ways and in either of the two holes, and contact the face of the locator in two other ways with the locator pin being inside or outside the groove. So it can be used in 6 different positions. So through trial and error, I think I figured it out and the photo shows how I think it should be used. If someone disagrees with the way I have it displayed, feel free to speak up.

I would like to speak to the web thinning terminology, I thought when you split the point, you WERE thinning the web. I always thought the two terms were synonymous. But that if you were just going to thin the web, you didn’t necessarily have to remove the material to the center tip of the bit, which would be splitting the point. This is probably why I had so much trouble with the instructions, and why I didn’t like the factory spacer, and the fact the grinding wheel cut the drill bit so far down the shank. So just thinning the web was a pointless waste of time.

Anyway I am glad the homemade split point spacer was something people could use. I actually thought the homemade wing cam was a cooler tool since it expanded the capabilities of the drill grinder. I do a fair job of hand sharpening the larger bits, but I took it as a challenge to expand the grinders sharpening range. I wanted to put my Drill Doctor 750 to bed forever. It sucks compared to the Black Diamond.

If you or anyone makes a split point tool, I would very much like to see it.

Ron
 
Ron,

The discussion helps. I think you know the subject better than I, but my impression is that web thinning, properly construed, is two completely equivalent grooves running parallel to the drill axis that are placed so that essentially the width of the chisel point is reduced. Point splitting would then be removing metal so that the chisel point gets two cutting edges. I got this impression from your idea to use a thinner spacer. My thinking is that a thick spacer aligns the drill almost tangentially with the wheel OD. That would be web thinning. Your thin spacer allows the drill to point more radially, allowing a shorter length of grind at a higher angle. From what I've seen online, the ideal point split angle is 42° (compared to a normal relief angle of 12°).

You inspired me, so I have to say that my unit is now in pieces, in the process of being stripped, derusted, primed, and painted. I'll have to wait to check out the results. Man, there was a lot of grinder dust/grease/dirt gunk covering this thing.

When I used my grinder, I did notice a ripple in the finish on the drill tip, and inferred worn bearings. Turns out I was right, and worse, the bearings are of obsolete design: Hoover 77202-16M. Essentially a 6202 with a 16mm ID. I did find some alternatives (listed below, with some web prices I found, in case it helps folks), and purchased some SKF NOS electric motor bearings. Did you replace your bearings? What did you use?

Jim


SKF 466306-2Z $15 ea + $4 shipping (I got these: they were rated /EM)
NDH 77502-16 $9.95 ea.
NTN 6202ZZ/16 $12 ea + $5 shipping
TIMKEN 202CCAG Sealed? $22.78
NACHI 6202ZZ-16 $9.95ea. + $9.95 shipping
KYK 6202-2RS-16-SRI2 Sealed $7.99 + $3.77 shipping
 
I did not have to change the bearings. Mine were tight and smooth running.

I did have to re-make the tube of the wing cam. I am not sure about all the measurements now, it has been a while, but there was .005” of wear on the shaft. If you pushed the shaft at the end, while it was in the guide, you could see some movement. That kind of wear is definitely noticeable and detrimental to sharpening the small drill bits. As a matter of fact, you canNOT sharpen small drill bits accurately with that much slop in the tube.
 
Ron, Can you possibly post the dimensions (at least the thickness) of your spacer and the factory spacer? I think the factory spacer is more for "web thinning". Your thinner spacer allows point splitting. This appears to be a model 1B. If anyone has the spacing attachemeng for the model 2B, I'd love to have the measurements for that (or, if you don't want it, I'd be happy to take it off your hands - please PM me).

Your periphery dresser, and your neoprene ideas are great. Thanks for a very helpful post!

Ron, or anyone else that reads this.

I hope you can help me.

I have come into possession of a Black Diamond Drill Sharpener, 1940-47 vintage.
It arrived to me completely dis-assembled, I have re-assembled it and it appears to be complete except for a "spacer" (part #20) on the parts list I have.

I have with it a number of collets for it and as far as I can tell, I have what is needed to dress the face of the wheel. However, while I have the web thinner attachment, I don't have the needed "spacer" to be able to dress the perimeter of the wheel.

I see on the PM forum that you have worked this problem and have made a spacer? for your machine.

I have no idea of the configuration of the part as I have yet to use the machine.

Also the Black Diamond company person I spoke with tells me that the machine must be properly calibrated in order to sharpen drills accurately. However so far I haven't been able to determine just what needs to be "calibrated". Your thoughts on this? It seems to me I should be able to "calibrate" the various parts and pieces to do the job they were designed for. It seems rather ridiculous that I should have to send the machine from here to the company costing a large amount of money for shipping and "calibration"

I am in Belfair, WA. and they are in Shrewsbury, MA.

Any help you can give me would be appreciated.

Jim Wright
[email protected]
 








 
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