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TT-50 chattering problem

Started by criscass, April 01, 2020, 12:41:47 PM

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criscass

Hi, I'm new to the forum. My name is Cristian and I live in Italy. I'm a cook/gardener/woodworker.
I've bought the stone truing jig (tt-50) and carefully read all the instructions before using it.
The jig works quite badly though.
The head holding the diamond/copper point has quite a lot of play and I think this is the reason why it often vibrates so badly that I have to hold it down with my hands and take very light passages, less than 0.25mm. I've tried different feeding speeds and off course truing in both directions. My stone was not badly ovalized or unevenly consumed when i stater truing it. I eventually managed to true the stone but I had to old down the head often and I ended up consuming a lot of stone since it made bad marks every time it chattered. Is this normal or I got a faulty piece?

van

Hi, I am also Italian.
Is your TT-50 the new model or the old one?
If it is the old model try to put two electrician clamps and you should solve the problem,
If it is the new model, ask for explanations at the Tormek assistance center via email, promptly resend, or wait for someone from the community, more experienced, to give you explanations.
Kindly yours

Ken S

Welcome to the forum, Criscass.

You should contact Tormek support. (support@tormek.se) Tormek redesigned the TT-50 last year. I think you probably have the older model. Here is a link describing the redesigned model.

Ken

https://www.tormek.com/usa/en/accessories/other-accessories/tt-50-truing-tool/

cbwx34

Quote from: criscass on April 01, 2020, 12:41:47 PM
Hi, I'm new to the forum. My name is Cristian and I live in Italy. I'm a cook/gardener/woodworker.
I've bought the stone truing jig (tt-50) and carefully read all the instructions before using it.
The jig works quite badly though.
The head holding the diamond/copper point has quite a lot of play and I think this is the reason why it often vibrates so badly that I have to hold it down with my hands and take very light passages, less than 0.25mm. I've tried different feeding speeds and off course truing in both directions. My stone was not badly ovalized or unevenly consumed when i stater truing it. I eventually managed to true the stone but I had to old down the head often and I ended up consuming a lot of stone since it made bad marks every time it chattered. Is this normal or I got a faulty piece?

If you have the older TT-50... try this...

Quote from: ionut on October 09, 2010, 08:11:54 PM
...
There is a simple way to eliminate those vibrations. follow the normal truing procedure but after you lock the TT50 on the universal support, take a long enough electrical tie put it through the diamond housing and wrap it all over the to part of the TT50 as it is mount it. You only need to tie it moderately, enough to back up the diamond housing to it's riding platform and to allow you to easily rotate the knobs. This will drastically reduce the vibrations or eliminate them so you can take the time to true the stone even for 10 min if you need a nice surface.
...

Ionut

... and also this post for additional info on this...

https://www.tormek.com/forum/index.php?topic=3053.msg16372#msg16372
Knife Sharpening Angle Calculators:
Calcapp Calculator-works on any platform (Just point your phone at the QR code)
or, a list of available Calculators

Ken S


criscass


micha

It really looks like the new model.
I have the same as in the link above and can confirm that it's not completely chatter-free.
There's quite a lot of play in the whole construction, so it allows for vibrations or chatter in certain conditions.
Unfortunately I'm still unable to foresee what these conditions are :) Sometimes it will chatter indeed.
However, turning the diamond insert some degrees made it signficantly better, but didn't eliminate the problem completely.

I'm already thinking along the lines of adding zip ties  ;)

cbwx34

If one of you (or both) could post a video... it would be interesting to me.  I don't see  a whole lot of play in the newer vs. older version.

The "zip tie" fix works on the older version... not sure about the newer one?

Quote from: Ken S on April 01, 2020, 05:42:45 PM
First, contact support.
Ken

Too bad this has to be the 'pat' answer... and that support doesn't readily monitor their own forum eh?  ::)
Knife Sharpening Angle Calculators:
Calcapp Calculator-works on any platform (Just point your phone at the QR code)
or, a list of available Calculators

micha

I had a closer look at the concept and, after some sleep, mounted it again.
While not sitting on the USB, there is obviously some vertical play (thus allowing the diamond insert some up/downward movement). This is greatly reduced when sitting on the USB, as the diamond holder's claw or jaw runs along the usb. That's a clever construction. Yet there's still some (very little) space left between the jaw and the USB to allow for some play. I'll have to measure that with a probe.
Then there is some horizontal play (the threading between the frame of the jig. This one is quite severe, between .5 mm, maybe a little more.

I'm not sure which is more likely to be the culprit here, maybe it's a combination of the two. It should be easy to temporarily take out either for testing purposes and then see what will happen (or hopefully won't :)).

I hope that description was not too confusing. I'll do some testing later and will post the results.


micha

Ok, back from testing.

I applied some PTFE thread seal tape (Teflon tape) to where it was needed to close any gaps until I could not feel any more play.
It's thin enough to adjust it by applying as many layers as needed and it won't prevent the parts from moving.

I wound it a few times around the upper part of the jaw and some went between the moving screw and the bushing.

Now i tried it with both the SG and the SJ stone (the latter had been quite badly mistreated by the TT-50 occasionally).
Either worked well, there was no chatter this time.
I'll try to attach pictures.

Ken S

Quote from: cbwx34 on April 02, 2020, 12:00:53 AM
If one of you (or both) could post a video... it would be interesting to me.  I don't see  a whole lot of play in the newer vs. older version.

The "zip tie" fix works on the older version... not sure about the newer one?

Quote from: Ken S on April 01, 2020, 05:42:45 PM
First, contact support.
Ken

CB,

There are several reasons that recommending support has become my 'pat' answer. Primarily, I recommend contacting support because it works. The two Tormek support people I have worked with over the years both have extensive Tormek experience. They are career people, and Tormek makes only Tormek. They probably work on more Tormeks in a week than most of us see in a lifetime. They also have access to almost fifty years of Tormek resources.

Beyond all of that, support is authorized to take action quickly when needed. How many times have we read posts where support has shipped new parts or replacement jigs or accessories?


Too bad this has to be the 'pat' answer... and that support doesn't readily monitor their own forum eh?  ::)

I agree. I think closer contact between Tormek and the forum would benefit both.

I have not heard of this problem with the redesigned TT-50. My 'pat' suggestion would be to try much lighter cuts, no more than half a microadjust number.

Ken

micha

...the story continues...

Some trueing sessions later the old chattering problem occured again. I can assure it wasn't because of the feed beeing to high, I always do very light cuts.
I took some pics of the insert and sent them to Tormek support. They confirmed it looked OK.
I felt the insert surface looked awkward anyway, very rough with the grits standing out quite a lot from the copper, so I decided to get a replacement just for testing.

So I did, with quite an interesting result. With the new insert there was no chatter and not even the slightest vibration, within the same setup, support bar, and stone.
I even removed the PTFE tape from the jig and had the same results.

This seems to lead to the conclusion that the insert itself can get into a state where it can generate some chatter. What are your thoughts?

My next experiment was a bit rigorous: I tapped the surface of the old insert with a hammer. This made the surface of the insert noticeably flatter. :)
Trueing with that insert again showed way less vibration or chatter. I'll probably repeat that procedure again.

I'd like to know how your TT-50 inserts look. Would be sure interesting to see if there's some sort of pattern.

The first picture shows the old insert before being treated. In the next there is the old one after being flattened and the new insert on the right.


RickKrung

Quote from: micha on April 09, 2020, 04:01:05 PM
...the story continues...
...snip...
My next experiment was a bit rigorous: I tapped the surface of the old insert with a hammer. This made the surface of the insert noticeably flatter. :)
Trueing with that insert again showed way less vibration or chatter. I'll probably repeat that procedure again.

I'd like to know how your TT-50 inserts look. Would be sure interesting to see if there's some sort of pattern.

The first picture shows the old insert before being treated. In the next there is the old one after being flattened and the new insert on the right.

micha,

Very interesting experiment.  I am having trouble understanding what it is you flattened with the hammer.  The working/diamond surface?  Or the round sides of the insert.  I would think the former would not do much other than possibly fracture some of the diamonds.  And the latter could make the insert more snug in its holder, which might help.  But I cannot tell which/if either of these you mean.  I cannot see where the original insert is flatter, in your second photo.

Rick
Quality is like buying oats.  If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.

micha

Hi Rick,

I actually hammered the working surface with the diamonds. You're right, that caused some fracture in some of the diamonds as well as some dimples on the hammer.   :D
Maybe some grits were pushed back into the copper bond, but there's less 'elevation' on the working surface now.  (I admit the second photo isn't taken from a very clever point of view to show that.)
Checking with a caliper while hammering showed actually a little upsetting deformation, but I didn't touch the sides intentionally. I think it's quite snug in the holder anyway thanks to the locking screw.
In the worst case I would have corrected that diameter in the tool grinding machine. Unfortunately it wouln't help much with the working surface, as I suspect the battle of the diamonds would end to the detriment of the grinding disc on the machine.  ;)

Take care
Mike