Mauser micrometer - missing part?

[JHM]

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 and how they fit (?) inside the brake ring, from both sides:




I dissassembled it for cleaning with the utmost care but evidently it was not utmost enough, it looks like it is missing a part (maybe 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 with 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?

 

[Deleted member 69715]

First, welcome to The Hobby Machinist forum; tell us a bit about yourself. Next, take a read here. Not your specific tool, but will give you a general idea about yours.
https://www.instructables.com/Evaluate-Repair-and-Adjust-a-Second-Hand-Micromete/

 

[JHM]

Hello:

... welcome to The Hobby Machinist forum ...

Thank you. 8^)

... a bit about yourself.

Not much to tell ...
Retired architect, all 'round tinkerer who understood early on that it is not yours till you've taken it apart and learned how it works.

... take a read here.

Thanks, I've been there.

Actually, reading it led me to post here to see if anyone had ever taken apart a Mauser 241 and could maybe tell me something about the part that seems to be missing, if there is such a thing.

I'll give it another read and see if I catch something else.

Thank you very much for your input.

Best,

JHM

Edit: is there somewhere here at HM where I can upload the Mauser catalogue? Liks fade and eventually disappear

 

[benmychree]

TO MY EYE, THE SPINDLE LOCK LOOKS COMPLETE.

 

[JHM]

Hello:

Hello:

... about the part that seems to be missing, if there is such a thing.

It would seem that there is a missing part.

Murphy is on the clock 24/07/365 so the part is very tiny, very hard to see and as a result, very easy to lose.
Especially if you don't have an exploded view of the thing to look at before you disassemble it.

I think I have managed to figure it out.

See here:



The purpose of the round cavity on that side of the lock is to hold a devilishly small ball bearing.
This ball bearing registers on the semi-circular slot that runs perpendicular to the axis of the thimble.

Once in place, it keeps the lock from turning as the ring turns and closes the lock by moving the roller.

Now to hunt for a small enough bearing, probably ~ 1.0mm or a tad less.

Any ideas about where to source one?

Best,

JHM

 

[pontiac428]

Far out. First, I thought to myself, I don't know anything about the Mauser Mod. 241, I'm only familiar with the k98. Then I thought, huh, Mauser built factories in Argentina at the turn of the century. In fact, all of Argentina's arms were built in cooperation with the German industry, up to and through the 1960's at least. It must be interesting to have that kind of production history, and to end up with tools that came through that industry. Unless I'm reading too far into it.

 

[JHM]

TO MY EYE, THE SPINDLE LOCK LOOKS COMPLETE.

Ahh ...
That is what I thought.
Especially after all the care I took while taking apart the micrometer.
But when I tried to lock the spindle, the ring spun around and the lock would not work.

See my last post, I think I've figured it out.

Thanks for your input.

Best,

JHM

 

[JHM]

Hello:

I hate to quote myself ... 8^°

... think I've figured it out.

Yes, apparently so.

I asked at a local micrometer repair outfit and at first the tech thought I was referring to the part (roller) that fits between the brake and the outer ring.

Told me he had one and offered to sell it to me.

But it seems that the micrometer where that roller comes from also lacks the ball bearing part.
Like I mentioned previously, it acts as a key to keep the the brake from turning as the outer ring is turned and without it the micrometer works but not too well.

Turns out that their donor micrometer is also missing the ball bearing part.
The fact that it is missing makes the case of it being very hard to source.

It is a very strange ball bearing, the type made to an unobtainable spec/diameter.

I went to see my friendly downtown bearings purveyor and they came up with two samples: 1/16" and 2.0mm.

The 1/16" (1.59mm) is small enough to allow assembly of the lock mechanism and sort of locks the spindle if you fiddle enough with it (a problem in itself) but the spindle retains a bit of radial play because the ball bearing does not sit tight in it's bed so 1/16" is a no-go.

The 2.0mm sample is way too big and the lock mechanism cannot be assembled.

So ...
1.59mm too small.
2.00mm far too big.

My guess would be something around 1.70mm / 1.80mm (?) but I'm just eyeballing it.

So unless I can find a parts list/diagramme with the spec ...

If anyone has any leads or ideas, I'd appreciate to know about them.

Or if anyone has one of these at hand and can (very carefully) take it apart to measure the bearing ... 8^D

Thanks in advance.

Best,

JHM

 

[pontiac428]

I am aware of cheap ball bearings in .177 size, they are called BBs.

 

[JHM]

Hello:

... cheap ball bearings in .177 size, they are called BBs.

Well ... 8^D

Thank you so much for that tidbit of very valuable data.
Had no idea BB munition was that size.

As a teen I had a pump powered rifle but it shot roughly 22 caliber lead thingies.

I'll drop by a fishing/hunting shop nearby and see if I can get two or three to try out and see what gives.

Who's to say?
Maybe it will work out.

I've been looking at a General Ball Dimensions and Tolerances chart.

From what can make out, the imperial chart goes from 1/16" to 5/64" (1.58750mm to 1.98438mm) and the metric chart goes from 1.50mm to 2.00mm.

Curiously enough, none of those sizes would work and that made me wonder ...

Could it be that Joe Mauser* pulled a fast one and used a rare spec for the micrometer's brake key?
ie: making for a rare/expensive replacement part instead of a standard size ball bearing?

Once again, thank you very much for your input.

Best,

JHM

* aquainted with but not related to Joe Cool.