The DBS-22 learning curve

[Elden]

   A couple of years ago I purchased a DBS-22. Until yesterday it has been sitting with a partially sharpened 1/2" drill bit in it. Yesterday I completed sharpening it. It wasn't too difficult to do after watching Alan Holtham' s well done video. If I would have stopped there, I would have thought that is easy.

   The second 1/2" bit didn't go as well. I had not taken the time to read the DBS-22  operator's manual since I had watched the video a couple of times. That is not a good idea as there is some pertinent information that the video does not cover. One is that the barrel of S stop needs to be screwed back into contact with the P stop. A second is that twisting the drill bit counterclockwise a little beyond the parallel marks will help when doing more than touch up grinding.

   Loading of the grinding wheel proved to be factor I had to contend with. As it became loaded, the grinding noise quieted down causing me to think it had reached the stop before it actually had. For larger bits plan to use the stone grader more than once during the bit sharpening unless you only are doing touch up grinding.

   Due to limited left hand usage, I have to operate the Tormek using my right hand only most of the time. Mr. Holtham tells you where to place your hands for best operating procedures. It took awhile to figure out the best operating position and the proper hand position for my situation. If I am not careful, the drill and holding fixture will climb up the grinding wheel due to the wheel rotating away from the cutting lip. I see where this could be an issue even for one using both hands. This tends to happen less when the wheel is kept clean of the loading issue. Would it be possible to reverse the motor direction so that the wheel would turn into the drill bit lip? Yes I know it probably won't happen at the factory because the honing wheel would be turning into the edges of tools when mounted in the jigs utilizing the USB in the horizontal position.

   I think a person can reasonably expect the grinding to take longer than the video shows. I believe Ken said 12 minutes (not all that time was spent in sharpening as part was solely instructional) for the video. If you look at the close up of the drill bit at about the 10 minute 30 second point, you will notice that the left primary cutting lip, as you face it, appears to have a chip in it. I do not see it in the later close-up. Thus more grinding would have been required than was shown. Also I have to add quite a bit of time for my sharpening because I am not nearly proficient as he is.

[Ken S]

Interesting post, Elden.

I agree, there is definitely a learning curve with the DBS-22. In my opinion, it is the most advanced of all the Tormek jigs. In the back of my head, I know that someday I must go through my drill index and regrind all the bits to four facet. I think that would either make me proficient or do me in!

You mention the possibility of reversing the direction of the motor. I am no expert, but I have seen some tool motors which can be reversed by switching two of the lead wires. I certainly understand why Tormek does not place a switch to reverse motor direction on all the units. In the general case this is quite logical.  However, you are a skilled, experienced user with special requirements.

I believe keeping the grinding wheel in optimum cutting involves more of a learning/experience curve than most us, myself included, realize. Being aware of sound changes during grinding seems important. Yesterday I reran a five minute grinding test wuth the black stone. I could not understand why   it did not outperform better than the standard stone grinding metal lathe tool bits (high speed steel with alloys). I redid the test after freshly truing the wheel. For most of the first minute, the stone made a powerful grinding sound. I was pleased. However, it quickly quieted down and gave me the same disappointing results the initial test produced. I do not know if my test is a good indicator. There may be factors I am unaware of. I do know that there was a definite change in the grinding sound. I have always paid attention to sound while grinding. I will intensify my focus in the future. I believe there is much to be learned by close observation. One of the many things I learned from being with Steve Bottorff for a day was how intensely observant he is of his grinding wheel. Intelligence, curiousity, persistency and experience make a powerful combination.

Do keep us posted.

Ken

ps Some guy recently posted a topic question in the Tormek general section about using one of the adaptor brackets to create a second horizontal position on the side where the wheel is incoming, as in the vertical position.

[Elden]

Ken,

   My Foley 308 chainsaw chain grinder has a reversible motor controlled by which direction the switch is flipped. The current grinders are not made that way thanks to OSHA getting ants in their pants. I suppose it is dangerous for the sparks to be thrown toward the operator. It would be nice to have the Tormek able to be reversed in like manner.

   I thought of mounting another horizontal base on the other side but the switch would have to be relocated. The USB could possibly tangle with the second horizontal mount when inserted into the first one as well. I'll try to check out the post you mentioned.

   Small bits are proving to be a challenge to get the secondary bevels ground properly without destroying one of the primary bevels. I am trying to do a #8 bit (0.199") which is a little larger than the minimum 3/16" size (0.1875"). The primary angles were not too bad to do. Plan to try again today.

[Ken S]

Elden,

I studied my Tormek (T7) earlier this evening to see if a fairly easy modification would be possible to add a second horizontal setting for the universal support.

A universal support with much longer "legs" would work nicely. Since I don't think that will happen, imagine this:

Look at your Tormek with the grinding wheel on the left. Push the long leg of the universal support through the horizontal sleeve next to the grinding wheel. That is the plane where the sleeves for the other side of the wheel would ned to be located.

I purchased an old XB 100 several years ago. I thought I had found a bargain. It was no bargain; it is the earlier model with only one holding screw. If you imagine one of the new, two screw XB-100 parts sitting between the vertical sleeves. The XB-100 should fit next to the sleeve on the grinding wheel side with no modification. A one inch diameter hole needs to be drilled in the XB-100 to slide over the right side sleeve. Once this is done, and the XB-100 fits flat against the Tormek housing, all that is needed is to drill the four holes for the mounting screws (already drilled in the XB-100) through the Tormek housing.

With this modification, your Tormek can be used in the horizontal position with the grinding wheel either coming into the work or trailing. No modification of the motor or switch is necessary.

The only other change needed would be changing the right sleeve tightening knob to a longer machine screw to clear the (vertical) sleeve.

I am thinking of having my Tormek modified this way. In my case, I will have the work done by a local machine shop. It should be a fairly simple job not involving much set up time.

Ken

[Herman Trivilino]

I purchased an old XB 100 several years ago. I thought I had found a bargain. It was no bargain; it is the earlier model with only one holding screw.

Should be easy to drill and tap for another holding screw. It's soft aluminum.

By the way, I think Elden has the much older Tormek with a rectangular housing. Not sure how that affects this plan.

[Elden]

   Thanks Ken. That is well thought out. I will have to check it out tomorrow.

   Herman you are correct, mine is the old rectangular frame. The switch is located on the side of the top where the second horizontal sleeve base would be positioned. I will either have to relocate the switch or see if a hole could be cut for it in the base which may not be practical.

   Thanks to both of you.

[Elden]

   Today I worked on sharpening some small drill bits. In doing so I found out a few things about the use of the DBS-22.

   It is possible to cause error to be introduced into the grinding due to improper pressure being placed on the attachment. If too much pressure is placed on the front of the drill bit holding fixture, flexing of the attachment can occur. Most is probably actually occurring in the slide areas. There may be a slight flexing of the USB as well.

   Some drill bits do not form a straight cutting lip when they are ground. Some have a concave cutting lip. This causes a problem when grinding the secondary facets. By the time the "point" of the four facet drill is achieved, the cutting lip (primary bevel) has been destroyed or is too thin to be durable. Larger bits that have this concave  have a wider primary facet and are not affected as much. Bits that do not have this concave lip make excellent four faceted bits.

   Smaller bits than 3/16 can be sharpened CAREFULLY. Small bits flex. I did a 5/32 bit successfully today. There IS a limit to how small can be done.

    On some small bits it is better to forget trying to get the point on the bit in my opinion.

   The attachment is a good one.

   

[Jan]

   My Foley 308 chainsaw chain grinder has a reversible motor controlled by which direction the switch is flipped. The current grinders are not made that way thanks to OSHA getting ants in their pants. I suppose it is dangerous for the sparks to be thrown toward the operator. It would be nice to have the Tormek able to be reversed in like manner.

Elden, it is not a problem to reverse a single phase induction motor. The simplest way, for testing purposes, is to disconnect the capacitor and start the motor by hand in the desired direction. 

But, in my thinking, T7 motors may not be reversed, because they have the unique Tormek drive system. Its design is asymmetrical, the more load you put on the stone, the more the motor shaft is pressed against the rubberized friction wheel. Thanks to this special reduction gear the torque of the stone is tremendous. 

Jan

[Elden]

Good point Jan. I hadn't thought about the drive mechanism possibly being compromised.
Thanks

[Ken S]

Several very good points in need of response:

Herman, Yes, the Tormek jigs are easily drilled and tapped. I did that for the HK-40 and HK-50 I made. However, with the XB-100, the sleeve without the locking knob is thin, too thin for enough threads to be effective. It was redesigned when converted to the double locking mechanism. The newer version is a real improvement.

Elden, I forgot you had the square design Tormek.

Jan, good point about the motor and the drive train. I forgot about the drive train.

I believe we have a very possible solution. My question is whether or not it is practical. I can have my Tormek T7 modified to work well with the second horizontal position. The parts cost approximately thirty dollars, more if shipping is factored in. machining costs could easily be fifty to a hundred US dollars. Would this improvement justify the cost?

I don't have an immediate answer for the question. I will put it on the back burner and ponder it.

Ken

[Herman Trivilino]

However, with the XB-100, the sleeve without the locking knob is thin, too thin for enough threads to be effective.

Ah, yes. I recall this issue. Perhaps one could drill a hole and epoxy a nut to the surface. Welding would be better, if that's even a possibility.

Or maybe counter sink a cap nut into the underside.

[Ken S]

You are correct, Herman. However, for twenty seven US dollars I can go to my local Tormek dealer and purchase the current version of the XB-100. It is enough of an improvement that I believe my shop time would be better invested installing the improved version.

(I could also buy the older version on a prominent online auction site for thirty seven dollars. Caveat emptor.)

Ken

[Rob]

I'm going to really bug you all now:

I had no idea my linisher style tool could do drill bits until I was reading something the other day. Now for drill bits my grinding operation goes like this:

1/ set platform at 60 degrees to belt
2/ hold one side of drill bit to grinding medium and grind until you roughly eyeball the middle
3/ flip over and do the other side so the middle remains a point and remains central.

Job done.  Total time taken, 20-30 seconds :-)

Whats more they drill like a knife through butter.

[Herman Trivilino]

To me it seems the process you describe, Rob, would produce two flat surfaces that meet near the center. But don't you have to rotate the bit as you grind so that you produce two conical surfaces? Moreover those surfaces aren't really conical as the cone angle has to decrease as you move away from the cutting edge. I've seen the practiced hand do this with ease and speed. My dad would do this on his dry grinder. When I inherited his bits I had to properly sharpen them all with my Drill Doctor. I think that as he got older his hand-eye coordination started to fail a bit.

Kind of like sharpening a knife by hand. If you're good at it you make it look easy.

[Elden]

   I was taught NEVER to rotate the drill bit when hand sharpening. The only time the drill bit should be rotated is when it is drilling a hole.  A straight movement down (when using vertical grinders) away from the cutting lip to give the relief angle can be used. It does not have to be, however, as long as the necessary relief is formed. The DBS-22 forms straight bevels if you don't consider the hollow grind due to the round wheel.

   The cutting lip should always held at 90° to the sides of the grinding wheel. That is why the cutting lips are placed parallel to the horizontal index mark on the DBS-22 holding fixture.

   When using the Drill Doctor and the industrial models made by Darex, the bits are twisted when sharpening. However, they are engineered with a special cam action that forms the proper levels.