Depth Micrometer Question

[FALPhil]

For years I have been using my calipers and metal rule to measure the tenon and C-shoulder depth on Mausers I have sporterized. Well, this weekend, I found a Browne & Sharpe #607 depth micrometer at a yard sale for $5.

I took it home to clean it,quite a bit of surface rust, but no pitting), and learn how to use it. Here is what I found:

The tool was not 'zeroed'. It is about 0.015 off of zero.
When I took the screw out of the thimble cap, the spring loaded ratchet ring came out in a couple of pieces.

I looked for an online user guide, and was spectacularly unsuccessful. How do you zero this thing? Are there longer rods for this model? Is it possible to find a vendor that sells parts for this model so I can replace the ratchet ring inside the thimble?

 

[sjk]

Some of the cheaper chinese ones do not have an adjustment on them but if I remember the B&S has a screw slot on the end of the thimble but I'm sure it has something to do with the parts that fell out. It's a trial and error way to go about it but once locked down, is foolproof. See if the depth rods have an adjustment on them also but most do not. Clean the pockets so that they will seat well. This is always a problem. Make sure your assessment is correct before you start. Very rarely do the B&S mics go out of whack but if they read "off" on all the extensions, the trouble is in the barrel. One thing though to remember that unlike a set of external mics the depth reading cannot be seen on the depth mics. It's covered up. On the external say, 1.00 mics, it's openly visible. It could possibly cause a .025 error,one full turn)to the beginner. No disrespect intended
LOL

 

[7C15]

Can you rotate the inner barrel like on a Starrett mic. But you can also move the nut on the end of the rod like sjk said.