What is different about this micrometer?

rivett608 · Aug 24, 2005

Game time.... lets play what is different about this 1" Starrett micrometer....... it is from early in the 20th century and I'm thinking there are 3 features, 2 little details and something unusual......

Dave A · Aug 24, 2005

It appears to have two friction collars, instead of one. It has the little hump with a screw in it on the top of the anvil.

Frank Ford · Aug 24, 2005

Good game. I notice that the decimal equivalents are rounded UP when they end in .000050, whether or not the preceeding number is even or odd. These days, I believe, we round DOWN if the preceeding number is even, and UP if it's ODD.

My mic lists 1/32 as .0312 and 3/32 as .0937, for example.

Asquith · Aug 24, 2005

Are the thimble and barrel intended to be removable? The right hand knurled collar seems to register in a small notch in the frame(?), and presumably the lug with the slotted screw indicates that the frame is split there.

John Stevenson · Aug 24, 2005

Frank,
Same redaings on that one for the examples you have supplied.

John S.

precision tools · Aug 24, 2005

The L.S. Starrett logo indicates it was made between 1880 and 1900. From 1900 on, it was L.S. Starrett Co.

The two knurled collars and clamp screw suggest the spindle is removeable. Was this an early attempt at a multiple caliper set where the spindle was shared between several frames? The small V groove at the back of the frame looks like the grooves used on inside mic sets to provide a reference surface when assembling.

It may have been a special made tool, as I do not see it in the 1900 catalog #17.
http://www.roseantiquetools.com/id97.html

rivett608 · Aug 24, 2005

You guys are good.... next time I'll have to dig for something harder to figure out.....

This is the Starrett version of R. J. Simpson's patent 706,696 of Aug. 12 1902 for a set micrometers with one thimble assembly and a set of interchangeable frames..... the 2 pages of patent drawings are in Cope's patent book.... this never was shown in a catalog or advertisement, at least any that I have ever seen and at least 2 examples are known.... I actually owned them both at one time

again, good observations!

precision tools · Aug 24, 2005

This brings up the question as to the date the logo actually changed.

My memory seems to be that it was 1895, but Catalog 17 states it as being 1900, and uses it. I have Catalog No. 27 that states it was 1909.

Since the patent was 1902, and the micrometer does not bear the Co., it must have been after 1902.

rivett608 · Aug 24, 2005

P tools I think a lot of study needs done on dating and logos of these early tools........ one thing that will really make that hard is these companies used older style parts for prototypes, specials and small runs and that is really going to mess up any general dating.... it will have to be by individual tool #...... such as Starrett #3 micrometers.

Why don't you share what you have found out so far....

precision tools · Aug 24, 2005

I am afraid, the information above is all I have, a shaky memory I cannot substantiate and two different Starrett publications with conflicting information.

I would guess that the change was made sometime in the earlier time frame, and completed around 1909 after the all the dies without the Co. added were ultimately replaced by attrition.

CoolWeldStudiosInc. · Aug 29, 2005

rivett608, THAT'S "gorgis". Great shape. Here is a Starrett mike predating that one - but no lugs with clamp screw - and has the knurled barrel ring with spanner hole abutting the mike frame like a #226 of the era of the "Type 2" that you show, rivett608 (please note, we have not restored this unit yet, hence the dirt and corrosion - not patina). Is this a "Bart Simpson"

pre patent unit? We can see what a pain it would have been to setup the frames so that all the spanner holes would be at 1 - 5 O'clock (with speeder facing you) to facilitate loosening the spindle assembly. Please keep in mind all our other early "Type 1" units do not have this feature.

jim rozen · Aug 29, 2005

That's not patina.

That's *pitting*.

It's always a shame to see a tool like that
that's gone to rust that much. No matter
what you do, it'll never be really right.

My view is to remove whatever rust can be
taken off electrolytically, and then leave
it at that.

What were you planning on doing, paint?

Jim

rivett608 · Aug 30, 2005

"It's always a shame to see a tool like that
that's gone to rust that much"

I think that mic is actually in pretty good condition for it's age..... that tool is about a hundred years old...... most things are not going to look brand new after a hundred years of use..... yes it does have some staining which is indeed a slight pitting.... antique tool collectors think of pitting as much much worse than this... kind of what you would expect to see on wrenches left outside laying in the grass for years........ anyway this type of stain was usually caused by acidly hands eating away at the metal....... in many cases the electrolytic process will destroy the finish and value of an old tool in this condition........ keep in mind that while this may still be reasonably accurate, no one is going to use it in a real word shop making a living...... I think it is fair to say that most folks that have 100 year old mics also have some newer ones around to use.... I do but even then I'll still use a 200 or 300 year old tool for fun.......

If it were mine I would most likely only wipe the dirt off and then leave it alone..... also keep in mind that sometimes photos show thing much better or worse than they are....... for it's age it's not so bad..... if only I could look that close to my prime at a 100 years old....

CoolWeldStudiosInc. · Aug 30, 2005

Jim, rivett608 is right, this tool is in very good shape for it's age. We do not leave the finish this way. At the Starrett factory we witnessed the workers doing sanding with 220 & finer grit paper to polish out natural steel surfaces. They also had runs of cast little stands made: A crank with a pinion geared to a Jacobs chuck at about 4:1 ratio. They were all over the plant. They polished small round tool parts with these. We of course use a polishing lathe to get the same factory (for the particular era) finish. The mike will be cleaned, oiled and calibrated.

rivett608 · Dec 21, 2008

While I'm looking at old posts I thought this one might be good too...... anybody see one?

AntiqueMac · Dec 22, 2008

Rivett,

I meant to ask you before. I have not found this micrometer listed in either catalog 17 (first version) or 18. They comport to the first catalog dates after the 1902 patent.

So, is the micrometer listed in any catalog? Which??

And, one with that collet like closure hump sold on eBay maybe a month or three ago - to someone we both know, but I can't recall who. Being feeble of of brains, I didn't study it closely.

So, possibly there are two?? That would mean there are going to be more!!

:drool5:

rivett608 · Dec 23, 2008

There are at least two, I once owned them both...... traded one to Roger Smith. Both were the 1" size.... I wonder if there are other sizes of frames out there? after all that was the whole point of this patent I think.

I have never seen this listed in any catalog or flier...... so just another mystery for now.

SalemRule · Aug 30, 2019

rivett608 said:
There are at least two, I once owned them both...... traded one to Roger Smith. Both were the 1" size.... I wonder if there are other sizes of frames out there? after all that was the whole point of this patent I think.

I have never seen this listed in any catalog or flier...... so just another mystery for now.

A friend of mine also has owned one for at least a decade.

So that makes three at least.

What is different about this micrometer?

Diamond

Titanium

Hot Rolled

Diamond

Stainless

Stainless

Diamond

Stainless

Diamond

Stainless

Aluminum

Diamond

Diamond

Aluminum

Diamond

Hot Rolled

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