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View Full Version : Adjustment on this 100MM mic??



J Tiers
10-22-2013, 11:16 PM
LOOKS like you adjust at the anvil, because there is no obvious adjustment on the barrel or thimble, no wrench hole or evidence that barrel is even separate from frame. No name on it either. (I do have a mic or two that have anvil screws like that but actually adjust elsewhere).

I've had it around for a while, and it checks out pretty close to correct. I like measuring tools to be as completely correct as I can get them, though, so it would be nice to get this one really "on".

If it DOES adjust from the anvil, that seems a tad "coarse", but the "pusher screw" may make it easier. (maybe it's part of the anvil??)

Anyone know the real story? Or the probable maker?

http://img.photobucket.com/albums/0803/jstanley/tooling/mic100mm1_zps62a7c997.jpg (http://smg.photobucket.com/user/jstanley/media/tooling/mic100mm1_zps62a7c997.jpg.html)

http://img.photobucket.com/albums/0803/jstanley/tooling/mic100mm2_zps17570fcd.jpg (http://smg.photobucket.com/user/jstanley/media/tooling/mic100mm2_zps17570fcd.jpg.html)

http://img.photobucket.com/albums/0803/jstanley/tooling/mic100mm4_zpsbf262088.jpg (http://smg.photobucket.com/user/jstanley/media/tooling/mic100mm4_zpsbf262088.jpg.html)

http://img.photobucket.com/albums/0803/jstanley/tooling/mic100mm3_zps55c53ce3.jpg (http://smg.photobucket.com/user/jstanley/media/tooling/mic100mm3_zps55c53ce3.jpg.html)

andywander
10-23-2013, 12:34 AM
Yes, you loosen the lock screw and then adjust the "pusher screw", then tighten the lock screw.

dp
10-23-2013, 01:34 AM
I think I'd try backing off the lock screw, pushing the anvil in too far then backing out the push screw, measure a standard length (pushes the anvil in), lock the lock screw, then turn in the push screw against the locked anvil. That allows the anvil to be set with the micrometer thread pitch which is a bit more controllable.

Paul Alciatore
10-23-2013, 01:56 AM
I like dp's method. I would add that you may need to do it twice. Do it the first time and then measure the standard with it. It will probably be off a bit. Then use the amount that you are off that first time to change the set point for the second effort. Check it again: it should be pretty close that time. You may need to repeat this a third time with another slight adjustment to the set point.

I have an older tenths mike that I set to "0.0000" years ago and locked it down. It has always checked OK ever since. If you are going for tenths, it is important to have the anvils completely clean.

J Tiers
10-23-2013, 08:24 AM
If you are going for tenths, it is important to have the anvils completely clean.

As it's a mm mic, "tenths" might be a tad coarse..... ;)

Point taken. of course. I rarely have trouble setting a mic, but didn't want to adjust the anvil if I was supposed to use a different (and less obvious) method

My impression on this unit is that it's French in origin, possibly due to the source (tag sale) which seemed to have a fair amount of French stuff.


Do French mics typically adjust this way? It seems rather crude and harks back to Systeme Palmer.... although Palmer does not seem to have provided a lock screw.
http://www.practicalmachinist.com/vb/antique-machinery-history/exceptionally-rare-historically-important-micrometer-palmer-220198/

The more common US method of adjusting the barrel seems to provide finer resolution, which is somewhat odd, since a mm mic is generally 2.5x more fine in actual resolution than a standard US mic(4 tenths, in US).

JCHannum
10-23-2013, 10:33 AM
The adjustable anvil is common to early and/or inexpensive micrometers. B&S misc used it early on, but I don't recall seeing it on Starrett mics.