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Micrometer spindle not clamping to handle

SteveM

Diamond
Joined
Sep 22, 2005
Location
Wisconsin
I have a Tesa V-mic that I'm cleaning up (it was frozen when I got it).

I got it all working except when I put it all together, the handle slips on the spindle.

It doesn't have the taper that Starrett mics have. It's just a straight shank.

The small handle looks like a ratchet, but it's a friction thimble. The screw spins in it when you reach the friction limit.

If I put a spacer in between the thimble and the handle, it will clamp the spindle to the handle. You can see how the spindle sticks out in the handle. The thimble only screws down to that point, and the handle has about 75 thou of play.

Is there a part missing, or is it me that missing something?

Steve
 

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I've got some Tesa mics, but mine are those Tesa Master ones with the rotating number blocks so may not be the same. On those at least, there's a skirt that unscrews at the top of the thimble revealing a set screw that fixes the thimble to the spindle itself. See if that part just above the knurl is a separable piece.
 
Looks to be one piece. The piece inside is separate and there IS a radial hole in it, so maybe that piece comes out. Tried tapping on it and it didn't budge, so I'll put some penetrant on it and try it later.

Steve
 
I think this may be the information you need. This is a depth mic but I expect they'll have used the same basic assembly. The TesaMaster mics also use the same thimble to spindle configuration

P1010496.jpgP1010499.jpgP1010501.jpg
 
BINGO.

That was it. Luckily it wasn't frozen like the spindle (so much dried oil it wouldn't budge).

Thanks.

Steve
 
I've got some Tesa mics, but mine are those Tesa Master ones with the rotating number blocks so may not be the same. On those at least, there's a skirt that unscrews at the top of the thimble revealing a set screw that fixes the thimble to the spindle itself. See if that part just above the knurl is a separable piece.
Hello everyone. I quote you because you said you had this model. I am new member in this amazing forum and need your help. I have a TesaMaster with amount of dirt inside recently buyed shared image.jpg
Can i have any information about disassembling and maintenance of this wonderfull micrometer?
Thank you all.
Teo
 
Do you see that smooth cap just to the right of the plastic window? It screws off and will pass over the knurl to its right. The plastic sleeve will also then be removable.
 
Do you see that smooth cap just to the right of the plastic window? It screws off and will pass over the knurl to its right. The plastic sleeve will also then be removable.
I can't unscrew it. I'll have to find a method to avoid damaging it...
 
Some layers of tape would provide a grip on the surface and protect it from the pliers you may have to use. Since it's a brass/steel interface you can be assured the joint is not rusted tight. The very slight compressability of the plastic sleeve provides some holding tension but you shouldn't have other serious impediments.
 
Thank you very much for your comment. I have tried with some protection and I have not been able to. It's really quite hard, although maybe I should keep trying with patience and care. As a last resort, I thought of drilling two holes in the flat part so I could use circlip pliers...but I haven't gotten to that point yet.
Greetings.
 
Hello again. I finally managed to remove it...although I ended up marking it, but it's not serious. I have separated the axis of the dials to work well and now I have a lag in the digits, which are a quarter of a turn ahead and makes it not clearly visible, and another lag in the mm scale, which does not go down to 0. Let's see how I fix it... advice is welcome, of course.20240529_205618.jpg20240529_205614.jpg
 
There's a keyway on the barrel and a plastic key that slides as the mic is opened and closed and rotates the blocks in the window. You may have to rotate one way or another before engaging the keyway.

But the mic is looking a lot nicer now.
 
New advances. I have managed, by loosening the Allen screw 1, and with the help of a screw, nut and washer, as a bearing extractor, to adjust it so that the mm coincide. I still have the tenths problem as to get the digits flat you would need to go back a third of a turn, so I don't understand the solution of rotating the barrel before engaging the keyway...maybe all 3 top screws marked '2' give access to a possible solution...? Greetings, thank you very much and sorry for occupying this post

20240529_205614.jpg20240530_124628.jpg.

20240530_115002.jpg

By the way, to adjust the mm scale I had to let the stem protrude 1mm...

Regards.
Teo
 
Good morning, machinists. I have found a patent by Hans Meyer, inventor of this mechanism, and you can understand a lot about how it works, but I still need to discover how to dismantle the rotating barrel...My mic has a brass pin next to the "0-50" hole held with two microscrews, instead of one screw that holds everything. Let's see if I can get a screwdriver that small... I attach the patent. Greetings to all.20240601_100330.jpg
 

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