For those that partook of this awesome offer and don’t know micrometers:
I got the 25-50 standard (micron) mike. It and, as far as I can tell from the web page the combimikes, are NOS units no longer in the catalog. I know the one I received is not current stock (101-116). Don’t worry. These are all still awesome, especially for 10 to 20% of the list price for current production.
The 101-116 I received was still sealed in the wrapper inside the case with the VCI paper (vapour phase corrosion inhibitor), but the foam in the case top was done. Well done. Disintegrated. If you find such, use a vacuum and don’t bother trying to replace it. It is nice, but the crumbs and offgassing will make the a mess of the mike.
The spindle on mine seemed stuck out of the box. I have seen this before, so, rather than ruin it, I knew: turn the spindle, carefully, IN, below the nominal minimum. Dried crud at the edge where the spindle enters the frame is the issue. Once it is clear of the edge, it comes off with a soft, lint free wipe, maybe with a little (moist, not dripping) odourless spirits. A wipe with a cloth moist (not dripping) with light instrument oil before turning he spindle back is all you need, followed by a wipe with a dry lint free to get rid of residue.
On the combimike, don’t let any spirits or oil get up the spindle into the works, as that will eventually cause issues (you don’t need to ask how I know) If it is stiff or clunky, note the included instructions for disassembly, cleaning, and adjustment. You don’t take the whole mechanism apart (unless you are very brave, or very stupid). I have never seen the counter on one of these go bad, other than through abuse or severe chemical exposure. Re-zeroing the counter is easy (see the guide- there is more than one design). Do it after checking/setting the zero for the spindle.
New units shouldn’t be out more than 1 or two microns (0.0001"), but no guarantee. Be sure the standard is CLEAN. The ends should be the nicest, most perfect mirror you have seen. Same for the anvil and spindle end. Use the ratchet or friction device. Unlike some of the low-end imports (Yes, I mean you, Harbor freight) these are reliable and consistent. With a ratchet, use the same number of clicks each measurement, and at the same speed. I usually go with three over about 1 second. With a friction thimble, apply at consistent, moderate speed and for roughly the same rotation every time. 1/4 to 1/3 turn is my usual.
Now I can demote my old NSK 5 micron (1/2 of 0.01mm) 25-50mm. It is a nice unit, and in some ways nicer to use than the Mitutoyos, but has a little wear on the faces, has an awkward ratchet, and only indicates to 1/2 of 0.01mm. I guess it sits in the case by the lathe and maybe gets loaned to students, now.