DBS-22 & Japanese Grindstone

[RichColvin]

I had to sharpen a ¼ inch bit yesterday that I was using on a piece of ash, and the piece has no tolerance for tear out.  I sharpened the bit on the SB grindstone as usual, then finished the primary facets on the SJ grindstone.  (I didn't worry about finishing the secondary facets as these are for chip evacuation, not cutting.)

This worked greatly !  Anyone else have similar experiences?  Has anyone seen differences with finishing the secondary facets also ?

Rich

By the way, this whole process took less than 5 mins !

[Ken S]

Rich,

What a clever technique. You are using the polishing stone (SJ) on the cutting edge and not wasting time on the non cutting edge.

Did you happen to try drilling a scrap piece with the bit sharpened only with the SB?

Keep up the good work!

Ken

[RickKrung]

I had to sharpen a ¼ inch bit yesterday that I was using on a piece of ash, and the piece has no tolerance for tear out.  I sharpened the bit on the SB grindstone as usual, then finished the primary facets on the SJ grindstone.  (I didn't worry about finishing the secondary facets as these are for chip evacuation, not cutting.)

This worked greatly !  Anyone else have similar experiences?  Has anyone seen differences with finishing the secondary facets also ?

Rich

By the way, this whole process took less than 5 mins !

I have not tried it yet, but as I prepare my T8 with some Norton 3X grinding stones to do the heavy lifting (grinding reliefs and removing defects, etc), I have been anticipating doing just that.  Grinding the primary facets (and perhaps cleaning up the reliefs) on the SB stone and finishing/polishing the primary facets on the SJ stone. 

Any particular technique to zeroing in on the proper angles, moving from one stone (SG or SB) to the SJ, which in my case is larger than either my SG or SB stones. 

Rick

[Ken S]

Rick,

You ask an interesting question.

First the short answer: Remove the jig from the support bar. Change the gring wheel. Reset the distance between the grinding wheel and the support bar. Then reset the clearance angle. Check you depth of cut. This should take less than a minute.

The DBS-22, like the TTS-100 turning tool setter, works so well because it standardizes variables. Both tools standardize the projection of the tool being ground by using slots. The tool is placed in the slot and moved until the tip of the tool touches the end of the slot. Then it is locked in place.

The distance between the grindstone is set using the factory standardized settings. The DBS-22 uses the hole in the plastic setting tool. Once this is set, the jig is placed on the support bar. The same plastic setting tool is used to set the position of the jig for the clearance angle. (Clearance is what makes the bit cut instead of just generating heat.)

The bevel angle is set on the jig. The standard angle is usually 118°. I suspect this angle is set by most users once and never moved.

The only real variable is the depth of cut. A bit which is just not quite sharp will require little steel to be ground away. A very dull drill will require more metal to be ground away.

Changing to a grinding wheel with a different diameter requires only the two steps with the plastic setting tool: resetting the distance between the grinding wheel and the support bar; and restoring the clearance angle setting. This procedure is the same whether you are moving between two grinding wheels which were both originally 250mm or moving from a 200mm 3X wheel to a 250 mm SB or SG.

The beauty of both the DBS-22 and the TTS-100 is that the Tormek engineers have done the math. The end user need only use the plastic setting jigs to consistently utilize all of this mathematical expertise. That's why I consider the DBS-22 Tormek's most advanced jig and the combination of the TTS-100 used with the SVD-186 gouge jig Tormek's most advanced combination.

Both combine simple repeatability and amazing flexibility. In my book, that's clever.

As a practical matter, I would only rough grind using the 3X and only use it with damaged of very dull bits.

Ken

[RickKrung]

Ken,

Yes, you describe the beautiful design and operation of the drill jig's basic and fundamental operation.  The Tormek setup jig and routine is great, but I was wondering if Rich had found any nuances to re-finding the primary facet angle after grinding the primary facet and then grinding the relief angle and then switching to the SJ wheel.   Rich made no mention of it, other than he had done it and it worked great.

I assume using a sharpie to blacken the primary facets would be a good idea for testing how closely the SJ wheel matches the SB grind but not having tried going back to touch up primary facets, and given that further grinding has occurred on the reliefs, which can change things, I am unsure how well the standard jigs and setup hits the previously ground primary facets (using the same initial grinding wheel, either SG or SB).  Changing to a different wheel, of different size changes everything and, as you say, throws things back to the basic setup routine. 

And, yes, my primary plan is to use the 3X wheels for rough grinding and fixing damaged and very dull bits.  However, as I believe I mentioned, I plan on seeing how well they may be used for rough grinding the secondary facets, and then possibly, cleaning them up with the SB wheel, in a similar spirit as going from the SB>SJ for the primary facets.  However, I believe I read somewhere that the 3x wheels leave a surprisingly good finish and as Rich said, the secondary facets are only for chip clearance, so maybe it won't seem necessary (I am hoping so). 

I will say this, sort of in my own defense.  The quality of all the finishes produced by the Tormek (SG or SB), compared to the Drill Doctor, is one of the things that drew me to the Tormek for drill sharpening in the first place (and drill sharpening was the overwhelming primary reason for me buying a Tormek).  I compared the grind finish from the DD to my original drills when there were some still in my drill indexes that hadn't been resharpened, and of those sharpened on my friend's professional drill bit sharpener.  The originals were far superior and smoother than any of the resharpened drills, although the Tormek (at the time, I had only an SG wheel) and my friend's finishes were quite similar and very acceptable, whereas the DD finish was grossly coarse, unsightly and completely unacceptable to me.   The option of finishing off the primary facets on the SJ wheel now offers a promise of approaching (or even exceeding) the original drill finishes (I've recently seen first hand what a beautiful job the SJ wheel does on knife bevels, going directly from the SB wheel).

The combination of the 3X wheels for roughing, SB wheel for grinding the primary facets and the SJ wheel for polishing them promises to be a nearly perfect drill sharpening scenario, for me.  I am quite excited to get to it.  I just have to make the bushings and flanges for holding the 3X wheels on the Tormek. 

Rick

BTW, even though this forum is hosted on some sort of web server, I would think that on a product specific forum/website, the brand's trade name (Tormek) would NOT be a mis-spelled word...

[Ken S]

Rick,

Just a quick thought: If you use a fairly large diameter bit, say 1/2" or 5/8" and sharpen primary and secondary facets with one wheel, either one of your 3X wheels or the SB; switch the set up to another wheel, say the SB if you are starting with a 3X or the SJ if you are starting with the SB. Touch just one lip of the bit, primary facet only. This will let you visually and tactilly judge the effect of the second wheel. You could use this same technique with the 46 and 80 grits of your 3X wheels.

A spare bit would be goid for this. Then you can keep the test.

Ken

ps Your post deserves a longer reply when I have more time.

[RickKrung]

Rick,

...snip...

Ken

ps Your post deserves a longer reply when I have more time.

Which part?  About drill bit sharpening or Tormek forum lack of spell checking on its own brand name?   

[Ken S]

I was referring to drill bit sharpening. I had not noticed the typo.

Ken

[RickKrung]

I was referring to drill bit sharpening. I had not noticed the typo.

Ken

You're still missing it.  There is/was no typo.  The word is "Tormek".  Spell checker finds it as a mis-spelling.  My point was that seems odd on a Tormek sponsored forum.   

Rick

[Ken S]

Rick,

I have not been really impressed with spell check in numerous places. I prefer to make my own mustakes, and often make up my own words if the programmed words don't jibe with my thoughts.
So, I missed the error.

Ken

[RichColvin]

Rick,

Frankly I didn't put a whole lot of thought into it.  The primary facet on a 1/4 inch bit is such a small surface area, that I swapped the stones & then simply reset the jig like I was starting from scratch.  I basically reground the whole facet.  (This technique probably falls into the category of not knowing I should do it differently.)

I probably could have used the SJ stone to make a secondary bevel (like on knives), and will look at that approach with larger bits.

Kind regards,
Rich

[RickKrung]

Rick,

Frankly I didn't put a whole lot of thought into it.  The primary facet on a 1/4 inch bit is such a small surface area, that I swapped the stones & then simply reset the jig like I was starting from scratch.  I basically reground the whole facet.  (This technique probably falls into the category of not knowing I should do it differently.)

I probably could have used the SJ stone to make a secondary bevel (like on knives), and will look at that approach with larger bits.

Kind regards,
Rich

Rich,

I think it would be nice not to have to use the SJ stone on the secondary bevel.  As you pointed out, it is just chip clearance.  However, if the primary facet is completely reground on the SJ stone, there is a good chance of overshooting the center-point, which would then require regrinding of the secondary to make the facets meet at the center-point (again).  If the center-point is not overshot on the primary using the SJ, you're golden. 

I'll be paying attention to these and other details when I do finally get to the point of grinding drill bits again.  It is competing for time with several other high priority and more time sensitive tasks, one being making the bushings and flanges for holding the Norton 3X wheels on my T8. Such is life, eh. 

Rick

[Ken S]

Rick,

Your first bit will tell the tale. The SJ is a polishing stone. It removes little if any steel. Your bit will show if it removes enough steel to shift the center point ir not. With a light touch, the center point might move. If it does, approaching the center line with the first wheel and finishing with the SJ should do the trick. This would be valuable information to know.

I just realized something: keeping the bit projection consistent as recommended not only keep the grinding consistent, it also keep the magnifier properly focused.

My gut feeling is to agree with Rich that just switching the wheels is accurate enough.

Ken

[Ken S]

I do not feel drill bit sharpening has received all the discussion it deserves. Thiis topic is centered around the SJ grinding wheel and the DBS-22. These happen to be two of Tormek's most expensive products, which narrows the field of users.

The SJ is a polishing wheel; by design it removes almost no metal and requires proper edge preparation with the primary grinding wheel graded fine.

The difficulty with the DBS-22 is that most users use it infrequently. A turner or woodworker may sharpen considerably fewer tools, however, these are sharpened much more frequently. A drill index may have many different size bits, however, most users generally use only a few sizes.

The DBS-22 is a very versatile jig. It is also one which requires more skill. This skill is within the reach of the average user, however, it does require focused practice to attain. The results are well worth the effort.

I do not see the extra time involved in finishing bits with the SJ as commercially viable. The specific example Rich gave would warrant the extra attention. It is nice to have that option.

As with many areas of sharpening, I expect changes in technique once the new diamond wheels are available.

Ken

[Grizz]

I do not feel drill bit sharpening has received all the discussion it deserves. Thiis topic is centered around the SJ grinding wheel and the DBS-22. These happen to be two of Tormek's most expensive products, which narrows the field of users.

The SJ is a polishing wheel; by design it removes almost no metal and requires proper edge preparation with the primary grinding wheel graded fine.

The difficulty with the DBS-22 is that most users use it infrequently. A turner or woodworker may sharpen considerably fewer tools, however, these are sharpened much more frequently. A drill index may have many different size bits, however, most users generally use only a few sizes.

The DBS-22 is a very versatile jig. It is also one which requires more skill. This skill is within the reach of the average user, however, it does require focused practice to attain. The results are well worth the effort.

I do not see the extra time involved in finishing bits with the SJ as commercially viable. The specific example Rich gave would warrant the extra attention. It is nice to have that option.

As with many areas of sharpening, I expect changes in technique once the new diamond wheels are available.

Ken

I have only been using the Tormek since mar 15 and I started out light pressure and slow movement. within a week I had the SJ stone and the DBS-22. I have a complete drill index so I got lots of practice. my bits were all in good shape to start with but I had never heard of the four facet grind, so I started out to practice that with the SJ stone. i had so much luck with with the bits that I never thought about anybody having problems with the DBS-22. I have the three stone Diamond set ordered and is suppose to ship in July.  so I don't know if a learning curve with the new diamond wheels will be drastic for me as that's how I learned from the start. especially with the Sj stone using light pressure and slow movement.