Any vintage tool experts here?

[Dr.Jeff]

I inherited a older set of outside mechanical micrometers made by the (now defunct) New Britain Tool Company (a brand under the Litton Tool Company). They were once sold through NAPA, probably in the 1970's. They appear to be in good overall shape, still in the original storage box, but no documentation other than the "New Britain" label on the outside of the box (the tools themselves only say "New Britain Made in USA").

I'd like to adjust the calibration setting on a couple of them, but these are not made like most micrometers that I'm familiar with. They have no hole for an adjustment wrench (and no wrench), and the thimble body is a one piece type (no two-piece friction adjustment). So how do you adjust them? I wasn't able to find any information about these specifically online; apparently they weren't very popular because I did not see any mention of them anywhere. I saw one reference online about older micrometers in general that suggested clamping the spindle in a vice and forcing the thimble off, but I won't attempt something like that without knowing more first. Anyone know how to adjust this type?

 

[lookforjoe]

I don't have an answer for you - but I do have a Lukfin and a bunch of old Starret micrometers that need servicing

 

[kmead]

Were my Great Uncle Elmer still alive I could get you an answer, he was an engineer there until the early 70s and those were likely among the products he

Sadly he passed in 1995. He was a great uncle in so many ways.

 

[Dr.Jeff]

but I do have a Lukfin and a bunch of old Starret micrometers that need servicing

While researching mine I found several sites that describe the procedure to clean and calibrate most micrometers - including ones like you have. It's very simple but does require a little "C" shape wrench (apparently included with most micrometers). The same procedure was listed for many different brands, and it sounds like pretty much every one out there is similar - except mine unfortunately. But for yours you can see how it's done online.