Unusual Starrett 0-6" Micrometer

[Electron2002]

I came across a very unusual Starrett Micrometer this weekend, the likes of which I have never seen before. It is an adjustable 0-6" Micrometer, with adjustment achieved by siding the micrometer head down the body, indexing it using a pin and locking it with the thumb screw. There is no model number on the micrometer. There are four patent dates listed. The oldest 5/28/1889 would refer to patent #404057, which is a patent specific to the design of this micrometer. The other patents appear to be general patents regarding micrometers. The newest patent is 4/17/1900, so it can't be any older than that.

I can't find any reference to it in any old catalogs that I have found. The DATAMP results for patent 404057, shows another photo of one of these, but it appears to be missing the clamping shoe for the thumb screw.

 

[454ragtop]

Pretty cool. If you don't get much response here, might post it over at Practical Machinist in the antique forum, bet some of the guys there would love to see it.

 

[davethorik]

I've seen one before, I believe it was for measuring thickness of a boiler wall.

Edit: I'm thinking of a different style of micrometer. Saw your post on PM, I'm sure they will steer you in the right direction

 

[crguy]

I've seen pictures before, and thought they were cool. If you're going to sell it, let me know.

 

[paulm12]

Very cool mic. I found a little info here (and there's alot on all micrometers): http://cofes.com/Portals/0/COFES_2012/COFES2012_MICROMETERS.pdf

 

[Electron2002]

Thanks for that link. That page has a lot of good information.

Very cool mic. I found a little info here (and there's alot on all micrometers): http://cofes.com/Portals/0/COFES_2012/COFES2012_MICROMETERS.pdf

 

[Plombob]

That's a very cool mike! Don't store it with the screw clamped down tight. Temperature changes can warp the mike.