Hahn & Kolb micrometer

Can anybody tell me how to read this micrometer?


It's made by Hahn & Kolb and has Nr.1731 stamped on it plus Messbereich. 10-20 (measuring range). My main problem is with the spring loaded plunger, with the graduations marked on it, which doesn't seem to connect to the moving spindle.

The only time I have seen something similar to this was for a line boring bar setting micrometer. The angled rest was set to the bar radius, the readout was hence then converted from a true diameter reading, to a radius reading but this was then converted to a 'cut' diameter reading. That's why I believe the setting tool in the case is a bar rather than the more normal length gauge. From memory they had a very limited measurement range. Used with 'Microbore' tooling generally for very accurate line boring of camshaft and crankshaft bearings.

The one I saw was not made by Hahn & Kolb though; my recollection was that it was possibly a Wohlhaupter.

Martin

Thanks for that Martin. TheThe setting tool is in fact a hollow bar measuring 15.00mm diam. This instrument was part of a consignment of tools that I inherited from my late cousin who was a keen model engineer and an inveterate collector of tools , new and old. The word magpie comes to mind. I can't think that I would have any use for it so will probably Freecycle it along with other unwanted items.

Bev

I looked on the H & K website, but unfortunately there is nothing listed and no sign of any of their legacy tools. If you like, I could post a link on an American website that I am a member of to spread the search wider.

H & K were the UK agents for Wohlhaupter if I recall correctly. Now a shadow of their former glory being no less than a logistics company I believe. They were based at Rugby and a lot of there 'goodies' were supplied to the BTH (latterly AEI but again now a multitude of car exhaust and tyre centres plus innumerable Tanning Studio's ) works there manufacturing turbines for power stations.

Bev - A bit of a background of where your cousin may have picked up such a tool may be helpful, where did he live? what major industries were in his area? Could be a start to finding where it may have come from. Are there any other markings on it? which could give a clue to where it was used (R or RR usually indicates Rolls Royce for instance, AS = Armstrong Siddeley, CT = Courtaulds Textile, etc,. )

Martin

Its past my bedtime now but I'll answer these tomorrow. Us octagenarians need our kip

old mart: Thanks for the offer, any source of info is welcome.

Martin: As you can see it bears a "cast in" HuK, Stuttgart logo, the stamped letters D.R.P. and a stamped triangle ( the letters under the J are WECO. Perhaps you can decypher.

My cousin worked for a company producing coatings for wood furniture, based in Salford. He travelled as a techniclly rep. nationally and abroad. He could have picked this item up anywhere.

Bev

Well that's got me flumuxed! DRP maybe the clue to where it was used and I would hazard a guess that the D stands for 'Deutcher' as in Germany. Over to any other suggestions from forum members.

A very nice instrument in beautiful condition may I say. Your late cousin was a very astute 'magpie' !

Martin

My money's on this being a peculiar indicating mic.

The features that it has in common with regular ones is the angled rod for limiting how far you can shove each part in the throat of it, the spring loaded measuring element and the +/- scale that seems to be independent of the main scale.

Bev: Does anything move up and down the scale when you press the plunger?

I suspect this is an updated rendering of the J WECO mark: **LINK**

https://www.discogs.com/label/1400961-J-Weco

… and it appears that Wizemann & Co know a thing or two about piston pins:

https://patents.google.com/patent/US5653204

Mmm …

MichaelG.

Edited By Michael Gilligan on 29/07/2021 07:29:38

Apologies … Not quite sure what happened there ^^^

Google ‘helpfully’ provided the URL for the referring page instead of the one I wanted to quote

[ Wizemann’s patent is ‘cited’ in that one ]

.

Try this: **LINK**

https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=4005686A&KC=A&FT=D

MichaelG.

Edited By Michael Gilligan on 29/07/2021 09:07:59

DRP is the equivalent of the UK "Patent" mark, rather than a manufacturer.

Cannot offer anything else useful, other than to say that the third anvil suggests use to measure round objects / and as said to set tools for boring.

Howard

First off my apologies but I have been offline due a lightning strike taking out our broadband yesterday. Openreach have just finished fixing it.

Martin: I'm not sure about the "astute" bit - there's a hell of a lot of dross that I'm trying to sort through!

Tim G: the scale is fixed to, and moves with, the plunger. I made a small video but can't see how to attach it to my post.

MichaelG: Thanks for the info but I'm not sure what the spacenet link is telling me about this instrument.

Howard: Thanks for your info. I can't see it as anything other than a "go/no go" gauge.

Anybody got any links to a German forum that may be able to shed some light (I'm grasping at straws here)

.

Assuming that you mean espacenet … the link is to a Patent in the name of the company whose J WECO logo is stamped on the instrument … the fact that their patent is for a rather special piston pin led me to infer that they might have an interest in accurately checking the size of such items.

MichaelG.

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P.S. __ Could you please check your Personal Messages, next time you are logged-on here

Edited By Michael Gilligan on 29/07/2021 15:30:50

Having relieved Bev of his micrometer ... I have removed the barrel for investigation

The knurled thimble moves things bodily within the confines of this flat:

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and the sprung scale at t'other end looks like this:

.

There is [as Bev has already noted] no apparent connection between this and the anvil

I suspect that things in the anvil area are gummed-up with hardened grease.

... We shall see

MichaelG.

Michael G,

Seems to be your week for interesting items in need of TLC!

Good luck with this one, lovely instrument.

Martin

A quick update :

Predictably enough, the dark spot in the screw-thread was grease, concealing a slotted screw.

… it appears to be very tight, so I am leaving it be for a while.

MichaelG.

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Which leads me to wonder … can this instrument really be that old ?

Ref. **LINK** https://www.lumberjocks.com/topics/306106

MichaelG.

It doesn't help with the ID, but it's not unique.
https://www.kenosha-reuse.com/ZION,-IL/Commercial/Mechanical/Refurbished/No-Warranty/Rare-german-mystery-micrometer-hahn-kolb.cfm

Bill

Excellent … Thanks Bill

MichaelG.