Brown and Sharpe Micrometer Information

[croach1776]

I have recently purchased a few B&S 0 = 1" micrometers and have done some preliminary research on use and care and repair. So any information would be helpful. I think that the type I have dont have the hole for the spanner on the sleeve and that the only way I have found to adjust them is to
remove the thimble enough to expose the collet collar or adjusting nut threaded onto the barrel. So my question is; Are there micrometers that use this method of adjustment as the only way to achieve zero. Thanks

[EricM]

Try this:
https://www.practicalmachinist.com/vb/g ... ter-94369/

Or this:
https://www.instructables.com/id/How-to ... icrometer/

Or this, if it's being difficult:
https://www.practicalmachinist.com/vb/g ... er-186808/

What models of B & S micrometers do you have? Many times, adjustment instructions can be found in the older catalogs. Pictures of what you have would be helpful, too.

[EricM]

The "adjusting nut threaded onto the barrel" you refer to is the nut used to adjust the threads to take out the play in them. It doesn't affect the calibration of the micrometer.

[tetramachine]

Some BS mics have a expanding nut on the end of the thimble. Loosen that and the thimble is free to slide into
Adjustment. It is a PITA.

[Harold_V]

The "adjusting nut threaded onto the barrel" you refer to is the nut used to adjust the threads to take out the play in them. It doesn't affect the calibration of the micrometer.

Not totally true. If the nut is truly loose, the thread of the spindle may or may not be centered in the nut, and most likely is not. As the nut is tightened, it causes the spindle to track from both flanks of the thread in the nut, causing the spindle to run in the center. The change in calibration may be miniscule, but it should not be addressed as insignificant.

H

[earlgo]

This subject was discussed in 2020 here:
viewtopic.php?t=109550&hilit=brown+sharp&start=12
Included is the fixture I made for just this issue of adjusting the zero. I know that the .010 is set on the mic but that is because the barrel is turned so the little hole can be seen.

adjusting fixture.jpg (53.25 KiB) Viewed 790 times

--earlgo