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Ian B
02-07-2008, 04:47 AM
I have a Mahr Millimess comparator; one of these:

http://www.mahr.com/scripts/relocateFile.php?ContentID=5627&NodeID=5223&FileID=7047&ContentDataID=21655

On the drawing, there's a "Lockable fine adjustment screw". When I turn it, nothing happens. Does anyone know what it's supposed to do? Also, if I remove the 4 screws from the back and try to look inside, are the jesus springs going to come flying out?

Thanks,

Ian

Your Old Dog
02-07-2008, 05:56 AM
Ian, I hope you don't have a lot of money into this thing! I have one also. My old employer used it to measure the variance, hence "dropouts", of magnetic tape while being run through at speed. It's sensitive enough to measure ideas, thoughts and notions!! Not much use in my shop where my hardware store yardstick seems to work pretty well :D

Ian B
02-07-2008, 06:34 AM
YOD,

No, not too much - only about $20. It's such a lovely thing that I couldn't resist it... As you say, supersensitive - individual markings show a movement of 1/000 mm.

Ian

Your Old Dog
02-07-2008, 07:26 AM
Mine was on a machine they tossed out at work. I took it so I could say I could measure down to a millemess. Then one day a guy asked me, "what's a millemes?" I stopped telling anyone I could measure down to a millemess till I find out just what the hell that is and what practical use it would be to me !

BadDog
02-07-2008, 11:58 AM
Put it on a stand, set the probe on your standard, adjust it so that it reads somewhere on the scale. Then, turning the adjustable screw, you should be able to get it to read zero. After that, everything you measure is realitive to your zero reference, assuming a good initial reference and rigid jig setup.

I've got a couple of these setup as indicating bench mics and one setup as a quantitative snap gage. And yes, very cheap they were, and I have no need for such accuracy, but they are "cool"... ;)

Ian B
02-07-2008, 03:25 PM
Yep,

I also expected that little knob to be something to put the needle in the middle of the range (wouldn't that be sooo handy) - but it doesn't. It doesn't seem to do anything at all!

Still not sure what it does...

Ian

ps - Tim Leech - remember that Victoria dividing head I bought off you? It's still in use, and still as lovely as when I bought it. Today, I was in my local (and only) scrapyard in Leeuwarden, somewhere in Friesland. What do I see upside-down in a muddy puddle? A 5" Victoria dividing head, all set to be shipped off to China to be melted down for scrap. It's missing a few bits, but in good shape otherwise.

Sob

Ian

lazlo
02-07-2008, 04:58 PM
I have a Mahr Millimess comparator; one of these:

Minor tool gloat: I bought one of these Millimess (1 ÁM = 40 microinch accuracy!) dial indicators on Ebay for $40, in great condition. The seller had listed it as "old, and the dial has yellowed."

Of course, the dial on a Millimess is supposed to be yellow :D

I use it to tram the head on my Millrite ;)

Alan in Oz
02-07-2008, 05:41 PM
Ian,
From memory the screw is a zeroing mechanism, it finely adjusts the needle to give a reference setting. If you take the back off nothing should "jump" out. ICR just how the adjusting mechanism works, I think through a small pin, but it should be obvious once the back is off.

Timleech
02-07-2008, 06:00 PM
ps - Tim Leech - remember that Victoria dividing head I bought off you? It's still in use, and still as lovely as when I bought it. Today, I was in my local (and only) scrapyard in Leeuwarden, somewhere in Friesland. What do I see upside-down in a muddy puddle? A 5" Victoria dividing head, all set to be shipped off to China to be melted down for scrap. It's missing a few bits, but in good shape otherwise.

Sob

Ian

Ian

Yes, I remember it well. I brought another one home from an auction sale a year or so ago, no-one else was bidding on it (it wasn't really a machinery sale, most people there probably didn't know what it was) so I saved it from the scrap man. I've no need for it, though I wish I'd had it when looking for one to motorise as a 4th axis. They're much better made than the anonymous (East?) German unit I used, & the oil bath lubrication would be a great asset in that role.
Did you save that one from its doom?
I've been to Leeuwarden by boat, nearly 30 years ago, I think it was there that we were trying to find a coal merchant. Our only heating was a tiny coal stove, & the weather was bl**dy freezing :rolleyes:
We found some 'coal', struggled to get it to burn, though!

Tim