Chatter marks on the wheel with the TT-50 diamond truing tool

[Sergio]

Hello everybody, I have a problem of vibrations with my T-7 when using the truing tool TT-50. I've used it for years without problems and now suddenly and with no apparent changes I get a terrible chatter on the wheel. It started about two weeks ago and it seems to worsen with time. I've had changed the speed, lower or faster, of the diamond travel or kept it at ~ 90 sec. but no changes.  The wheel is apparently solidly secured. Can  anybody help me? Thanks a lot.

[Herman Trivilino]

Is the mainshaft bent?

[Mike Fairleigh]

Has the hex head set screw loosened up?

[Sergio]

The shaft looks OK. I removed the wheel and turned the inner washer which had the round side against the wheel so that now that side is against the shaft, reassembled the wheel and external washer and tightened the nut carefully. The chatter is still there.
So I tried to grind with the grinder on the floor to eliminate the possibility that the table was vibrating but nothing changed.
I do not have anything in mind. The good thing is that the chatter is very consistent (like a resonance effect on the lathe) and probably will not affect too much the sharpening. But certainly would like to know what cause it.
Also, when the wheel turns there is a vibrating noise that seems to came from the motor.
Hope someone will a solution. If necessary I can post a picture of the chatter marks.

[Mike Fairleigh]

The part I was asking about was the large set screw in the truing jig itself.  The one that holds the cutter in place.  Is that still tight?

[Sergio]

Yes Mike, I tightened it but nothing changed.

[Sergio]

I was finally able to reduce although not eliminating the chatter on the stone. I removed the profiled leather honing wheels (LA-120) which I just recently acquired. In my opinion the vibration comes from the motor. The situation is annoying and wander if anybody has a similar problem.

[Jeff Farris]

Sergio,

Just to be clear, are we talking about a T-7 with a steel frame, or a T-3 with a plastic frame?  I've experienced the harmonic chatter with a T-3, but never with a T-7. 

If it is a T-7, take the honing wheel completely off, start the machine, and carefully lift the motor away from the drive wheel.  It should make virtually no noise whatsoever while running. If it is noisy, seek warranty repair from your dealer. If the noise is only present when the motor engages the drive wheel, remove the stone, pull the shaft out, lube the nylon bearings with a Teflon based spray lube and re-assemble.

If the machine is running and sounding normal in every use except when using the truing tool, loosen the Allen screw that secures the diamond tip, rotate the tip one quarter turn and re-tighten. The diamond chips are in the bronze binder in a completely random pattern. Occasionally, as they are exposed odd things happen because of the pattern. Approaching the chips from a different angle usually clears up the problem.

[Sergio]

Hello Jeff,
I did what you recommended and here is the result: no chatter. To be more detailed, the motor is NOT completely silent but the noise do not feel too bad, rather smooth.  In any case I did not have a Teflon based lubricant and used a spray lubricant for electric motors and also rotated the copper/diamond tip. Then I used the truing tool and got a chatter free result. Tomorrow I'll do a more extensive testing.  I did not do things in stages so I do not know if it is was the lubricant or the diamond tip to fix the problem. I sense that it was the lubricant since this morning I lubricated the shaft with Vaseline (did not know what else to use) and the chatter remained only in the 20% external part of the stone. The external part of the wheel is where the chatter marks where always more evident.
Thanks, Sergio

PS: You think I should ask for a new motor for the low noise? Furthermore, could you tell me which is a "Teflon based lubricant" that I should use? I also feel that the Nylon bushing are not too appropriate for a machine that all said and done cost $1000  and Tormek should think abouth an upgrade.

[Jeff Farris]

The nylon bearings are an excellent choice for a low speed operation in an environment bathed in abrasive-filled water. I'm not sure about Teflon lubes where you are. In the States I recommend Tri-Flo and Boeshield T-9. The bearings are really are not very demanding. White lithium grease works nicely, too. Just don't get carried away. It only needs a little. I think your Vaseline will be a fine choice.

One more trick regarding harmonics. Start truing from the outside and work toward the machine. This works on both the T-3 and the T-7.

[Sergio]

 Unfortunately today I stated to have again the chatter. When the diamond reaches the third exterior of the stone one can hear an "harmonic  noise and this leads to the chatter marks which now are more thin and numerous. I noticed that the internal washer is   rubbing against the black nylon bearing (by the way are these bearings or bushings?). Could this friction lead to the  harmonic noise and then chatter? I will trying with lithium grease while waiting for the T-9 or the DuPont dry Teflon lubricant I found at Amazon.
If this will not solve the problem I will try the warranty but I do not know how this work.
I have another question: I have a 7inch Baldor grinder that I use with the extra Tormek universal support. It was not easy to find the right eight but I believe now I got a good compromise. My question is, can I use the TT50 to true the dry stone of the Baldor?
Thanks for the time and help.

[Jeff Farris]

... My question is, can I use the TT50 to true the dry stone of the Baldor?
Thanks for the time and help.

No, this will not work. Get a stick dresser with an abrasive matrix similar to the diamond tip. Packard Woodworks in the U.S. sells a very good one called the "Diamond Jim".

Try working from the outside in, before you go to any other extreme measures. Also, I am guessing from the number of times that you are truing that you are taking very thin cuts...this will contribute to the vibrations.

[Herman Trivilino]

I noticed that the internal washer is rubbing against the black nylon bearing (by the way are these bearings or bushings?).

That internal washer is, I think, designed to rotate while making contact with the bearing.

As to the issue of bearing versus bushing, I think it's semantics.  You can think of a bushing as a type of bearing.  A bearing is something that "bears" the weight (force) of a rotating shaft.

[Ken S]

Sergio, I have used this diamond dresser with good results:

http://www.leevalley.com/us/wood/page.aspx?p=55075&cat=1,43072,43080&ap=1

It's inexpensive and does the job well.

I think the bearing/bushing debate is a result of thinking in terms of a high speed dry grinder.  At 3450rpm, good bearings are essential.  At 90 rpm the issue loses most of its importance.  A question for Jeff:  YOu have probably used a Tormek more than anyone.  Have you ever had to replace a nylon bushing?  If so, after now much use?

How deep a truing cut are you making?

Ken

[Jeff Farris]

Ken,

Whether I've replaced a bearing/bushing is an unrealistic question, since I've always had a new demonstrator machine to use. We have some heavy use clients that replace bushings every couple of years, while using the machine daily for several hours a day. Most bushings that are replaced could have lasted longer if the machine had been cleaned thoroughly after use.