Mauser micrometer - missing part?

[Julius Henry Marx]

Hello:

I have a Mauser 0-25mm micrometer, apparently* the basic Model 241.
The brake is not working properly, I fear it is missing a part.

This is a photo of the Model 241 I have:



This is a photo of the two parts belonging to the brake assembly (inside the brake ring):



Edit:
Here is a photo of both sides of the brake ring.



I dissassembled it for cleaning with the utmost care but evidently it was not enough, it looks like it is missing a part (a very small ball bearing?)

The micrometer works properly, '0' is '0' and the thimble runs smoothly, albeit a bit loose for my liking.
If only I could find the damn wrench ... 8^°

I have looked all over the web for an exploded parts diagramme or instructions on how to do maintenance work on it, to no avail.
I'd appreciate any pointers on how to fix this if at all possible.

Thanks in advance.

Best,

JHM

* I have a scan in *.pdf format of an early/mid 1950's Hans Lehmann (a machines and accessories dealer in Lörrach, DE) photo catalogue of what seems to be the whole line of measuring instruments manufactured by Mauser-Messzeug GMBH at that time. Unfortunately, only photos and model numbers, no descriptions or details. Is there a place here at PM where I can upload it for future reference?

 

[Bakafish]

Is there a similar detent in the thumb wheel? It would be helpful to see the other relevant parts.

 

[Julius Henry Marx]

Hello:

... similar detent in the thumb wheel? It would be helpful to see ...

No, there isn't anything on the wheel.
Added a photo to the OP for completenes' sake.

These micrometers are still available all over and most of them are in perfect shape, these chaps really knew what they were doing. It is surprising that there is not nore information on the web.

On another tack: any idea where I can upload the catalogue?

Thanks for your input.

JHM

 

[maynah]

Say the magic "woid" and you just may find one.
If you post this over in the antique section you may find help there.

 

[Julius Henry Marx]

Hello:

Say the magic "woid" and you just may find one.

Woid or word, no idea which one it may be. 8^°

... post this over in the antique section ...

Thanks for the suggestion, but I don't think so.
As expected, while attempting to post something related brings up a question:

"Has this topic already been discussed?"

Below follow a list of topics which fit the same subject.
ie: Mauser+micrometer.

Among them this one.
Thanks for your input.

Best,

JHM

 

[mftmachining]

Hello:

I have a Mauser 0-25mm micrometer, apparently* the basic Model 241.
The brake is not working properly, I fear it is missing a part.

This is a photo of the Model 241 I have:

View attachment 395164

This is a photo of the two parts belonging to the brake assembly (inside the brake ring):

View attachment 395165

Edit:
Here is a photo of both sides of the brake ring.

View attachment 395168

I dissassembled it for cleaning with the utmost care but evidently it was not enough, it looks like it is missing a part (a very small ball bearing?)

The micrometer works properly, '0' is '0' and the thimble runs smoothly, albeit a bit loose for my liking.
If only I could find the damn wrench ... 8^°

I have looked all over the web for an exploded parts diagramme or instructions on how to do maintenance work on it, to no avail.
I'd appreciate any pointers on how to fix this if at all possible.

Thanks in advance.

Best,

JHM

* I have a scan in *.pdf format of an early/mid 1950's Hans Lehmann (a machines and accessories dealer in Lörrach, DE) photo catalogue of what seems to be the whole line of measuring instruments manufactured by Mauser-Messzeug GMBH at that time. Unfortunately, only photos and model numbers, no descriptions or details. Is there a place here at PM where I can upload it for future reference?

Hi, to be honest, i have never seen a ringbreak like this. And i repaired and restored hundreds of Mauser mics. My question: If you look on the mic from above, there should be a small slit in the top of it. This normally corresponds to a nose on the inner ring to prevent the ring from turning. Only the outside ring should spin freely. I can´t see any nose on the inner ring of your mic. Since this ringbreak is relying on friction, you could try to degrease it and see if there´s any improvement.

 

[Julius Henry Marx]

Hello:

> ... never seen a ringbreak like this.
If you are in the US, it could be because it is German made, probably from an early 40's?
I have not seen these brand/model micrometers show up on US eBay.

That said, I think I have found the problem but not a useful solution.

The missing part has to be one that fits in the only available place for it: the 'dimple' on one of the lock's (the inner ring) surfaces.

The only thing I could think of which would fit inside it was a very small steel ball bearing.

Like this:



Then, with the ball in its place, you fit the ring in place.
This can only be done in one way: with the ball facing towards the business end of the spindle.



The ball fits within the slit you see (sorry for the bad photos) and generates interference when you turn the brake. It works because the ball can move (minimally) along the slit, allowing the brake to close on the spindle.

It is very ingenious but also very complicated: a steel ball of that size is easily (very) lost.

To add insult to injury, the bloody ball is not of a standard size and I have not been able to find one that fits as it should.

The ball I have put in place (~1.58mm) is a wee bit smaller that the original one.
The brake locks the spindle but as the diameter of the ball is a tad smaller than the width of the slit it slides into, the spindle will have play: ~ 1/3 of 0.01.

The next size ball I was able to find (2.0mm IIRC) was too large and I have no idea what size it would have to be to work properly.

I have not found an intermediate size but I guess it should be ~ 1.60 /1.62 mm.

So ...
Play in a a 0.01 micrometer spindle?
Right.

I have spoken to a couple of micrometer repair houses about this and they happened to have two of the three brake parts to offer but not the third one.
ie: the one I need.

Strange, thought I ...
Not so much: they probably had more than one of these micrometers with the non-standard size AWOL steel bearing, as such irrepairable.

It's a pity as the micrometer is in perfect shape in spite if its age.
I got another Mauser (with a different locking mechanism) in pristine condition for a song, so the problem sort of got solved but not as I intended.

Thank you very much for your input.

Best,

JHM

 

[michiganbuck]

From here it looks like the catch direction should go toward the long angle.
post #7 looks right
Post #1 looks wrong.

 

[Julius Henry Marx]

Hello:
> ... looks like the catch direction should go toward the long angle.
> ... post #7 looks right
I'm not sure I understand what you mean ...
But the micrometer has been assembled with the brake set up as depicted in post #7.

Thanks for your input.

Best,

JHM

 

[mftmachining]

Hello:

> ... never seen a ringbreak like this.
If you are in the US, it could be because it is German made, probably from an early 40's?
I have not seen these brand/model micrometers show up on US eBay.

That said, I think I have found the problem but not a useful solution.

The missing part has to be one that fits in the only available place for it: the 'dimple' on one of the lock's (the inner ring) surfaces.

The only thing I could think of which would fit inside it was a very small steel ball bearing.

Like this:

View attachment 409661

Then, with the ball in its place, you fit the ring in place.
This can only be done in one way: with the ball facing towards the business end of the spindle.

View attachment 409662

The ball fits within the slit you see (sorry for the bad photos) and generates interference when you turn the brake. It works because the ball can move (minimally) along the slit, allowing the brake to close on the spindle.

It is very ingenious but also very complicated: a steel ball of that size is easily (very) lost.

To add insult to injury, the bloody ball is not of a standard size and I have not been able to find one that fits as it should.

The ball I have put in place (~1.58mm) is a wee bit smaller that the original one.
The brake locks the spindle but as the diameter of the ball is a tad smaller than the width of the slit it slides into, the spindle will have play: ~ 1/3 of 0.01.

The next size ball I was able to find (2.0mm IIRC) was too large and I have no idea what size it would have to be to work properly.

I have not found an intermediate size but I guess it should be ~ 1.60 /1.62 mm.

So ...
Play in a a 0.01 micrometer spindle?
Right.

I have spoken to a couple of micrometer repair houses about this and they happened to have two of the three brake parts to offer but not the third one.
ie: the one I need.

Strange, thought I ...
Not so much: they probably had more than one of these micrometers with the non-standard size AWOL steel bearing, as such irrepairable.

It's a pity as the micrometer is in perfect shape in spite if its age.
I got another Mauser (with a different locking mechanism) in pristine condition for a song, so the problem sort of got solved but not as I intended.

Thank you very much for your input.

Best,

JHM

Very good info´s, thanks I´m located in Frankfurt/ Germany. Sad, this is the only Model series i don´t have on hand here. Yours was built between 1951 and around 1965. I have Model 241 here, but with a different brake. If you are also in Germany, lets get into contact.
Regards

 

[Julius Henry Marx]

Hello:

> Very good info´s, thanks ...
You're welcome.

> ... located in Frankfurt/ Germany.
> ... the only Model series i don´t have on hand here.
That's life ... 8^D

> Yours was built between 1951 and around 1965.
Yes, after replying to your post I realised that I had calculated the dates wrong.

> ... Model 241 here, but with a different brake.
This is the one I purchased recently:


A very good deal for the equivalent of ~ US$12.00.
Everyone wants shiny, new and electronic these days. 8^/

Just had to slowly and patiently get rid of all the hardened oils present everywhere.
I was told it had been in a drawer for more than 20 years.

> If you are also in Germany ...
No, rather far away I'm afraid.
Across the pond but in the southern hemisphere.
Buenos Aires, AR.

Should you find any data on this specific 241 model, I'd appreciate your sharing the information you find.

Best,

JHM

 

[mftmachining]

Thats the series i have.
Perhaps you could slaughter an old one from a different company. This is one of an Steinmayer, made in the same time.

You could also look at my youtube channel if you´re into mic´s.
Perhaps interesting for you.
@mftmachining

 

[Julius Henry Marx]

Hello:

> Thats the series i have.
> ... an old one from a different company.
A few months ago, I almost got my hands on another one exactly like the one with the missing part. Besides being in sad shape, it was also missing a basic part (the rachet stop) without which getting an accurate measurement is rather a folly.

But the brake was apparently intact so I was willing to gamble a few dollars on it.
If the brake was missing the same part as mine, the body (thimble, spindle, etc.) could eventually be of use, albeint with some surgery, as a stop of some sort.

I agreed on their (suitable) asking price which was duly duplicated at the last moment.
As it made no sense, I withdrew my offer.

The Steinmayer photo you kindly posted seems to be a slightly different design: I see what seems to be a spring pushing the cylinder (?) and what in my sample I take to be a ball bearing, in yours looks like a different part altogether. Probably won't get lost as easily as a 1.6mm ball bearing held in place by the fickle will of the micrometer gods. 8^D

If only an exploded view diagramme from Mauser were available, we'd all know what it was about, but I have searched all over to no avail.

Thank you for your input.

Best,
JHM

 

[Julius Henry Marx]

Hello:
> ... shoulder on the outer ring is supposed to push the inner part roller ...
When I first started with this, I tried reassembling it in every way possible but the only way all parts would fit together was the way you see in post #7.

And it took me a good while to figure out how it worked.

The outer ring has a circular outer perimeter, concentric with the spindle but its inner perimeter is not.

When the assembly is in place, the inner ring is kept from turning by the ball bearing/slot and the close fit on the spindle.

Now, when the outer ring is moved (in the photo, clockwise), the shoulder (which cannot move) pushes the cylinder against the inner perimeter of the outer ring, the net result being that the inner ring presses against the spindle more and more till it locks it.

The problem with not having the right size ball bearing/part is that even though the inner ring is locked against the spindle, the whole assembly (thimble, spindle, inner ring and outer ring) will have play because it depends exclusively on the proper fit between the ball bearing (or whatever shape part goes in the 'dimple') and the slot it moves in to keep everything tight.

Thanks for your input.

Best,
JHM

 

[John Garner]

Is the problem that the ring doesn't grip the spindle firmy enough, or that there is excessive axial play when the spindle is locked?

 

[Julius Henry Marx]

Hello:

> ... problem that the ring doesn't grip the spindle firmy enough ...
No.
There is play once you get the spindle to lock.
The ring does grip the spindle firmly but you have to work on it due to the play.

You can jiggle (radially) the thimble and actually see the play which amounts to ~1/3 of a division.

This because the ball does not sit properly in the slot due to a) being smaller than it should be or b) the wrong type of part ie: maybe the original part is not a ball bearing but some sort of pin.

That would make sense.
I cannot get around the idea that Mauser would use a ball bearing of a non-standard size for this.

Thanks for you input.

JHM

 

[jccaclimber]

1.6 mm dowel pins are not common, but 1.5 mm dowel pins are. Would that be suitable, or too loose?

 

[John Garner]

It's worth noting that 1/16 inch is pretty close to 1.6 millimeter.

 

[Julius Henry Marx]

Hello:

> 1.6 mm dowel pins are not common, but 1.5 mm dowel pins are.
I see ...

> Would that be suitable, or too loose?
The steel ball I put in there in place of what the original parts would be (no idea what shape of size it is) is ~1.58 mm. The next available (standard) size is 2.0 mm.

~1.58 mm seems to be too small and 2.0 mm is too large. 8^/

@John Garner
> ... 1/16 inch is pretty close to 1.6 millimeter.
In fact, the ~1.58 mm ball is a nominal 1/16" ball purchased (as well as the 2.0mm one) at a bearing distributor.

Like I mentioned earlier, I have come to think that the original part is not a steel sphere but something else, obviously just a guess.

I (indirectly) measured the width on the slit in the frame using a small SS drill.
This 1.50 mm drill shank fits perfectly at ~50% of it's diameter which leads me to think the missing part may not be a steel sphere but maybe not a pin either.

At least, not a pin with a flat end on either side.



Maybe a pin sliding along the slit and having a semi-spherical bump in the middle?
No, much too expensive to manufacture.

And then there must have been a reason to start making the 241s with a different brake design.

Here's hoping someone out there has a maintenance manual for this model 241 Mauser or can post photos of a disassembled one.

Thanks for your input.

Best,
JHM