A diffrent set of michrometers

[country gent]

Was Looking thru Dads tools today. ( he was a tool and die maker) These were split 3 ways. All the usual for a tool maker from the 60s to date, A lot made by him and my grandfather. Boring bars, cutters, a block for grinding threading and groove tools, a neat little set up for indicating round in the mill, Sine plate 5" with the rails hold downs and bolts. A shaper/planer gage. A couple small grinder vises Dad made. A boring head for Bridgeport mills. Home made clamps around spindle nose. Angle plates couple sets different sizes and one with 3/8 square holes. the old tool holders for lantern style tool post, one heavy straight 1/2 tool holder for shapers. a couple knurling tools single wheel left and right, a bunch of cutters lathe HSS and cemented carbide, slotting mills and a few end mills. Some indicators. Measuring tools a old set of helios calipers with the .200 rev dial 0-.100 - 0 and Inside tips that require .400 be subtracted from measurement. Small hole gages both flat end and ball. Several sets of dividers herempidite, inside, outside, and dividers. A Starrett 0-1 depth mic only 1 rod with it. A 436 0-1" Starrett mic .0001 grads ( Vernier on thimble). The one Im not familiar with is the Starrett No 221 0-1" mike. Its a double thimble mike with spring loaded friction thimble. carbide faces, lock, and direct reading .0001 on second thimble. Ive used B&S Vernier mics, some starretts both indicating and normal, Federal indicating mics, and some digitals.

Instructions say to measure part touch and go 10 grads on second thimble past and let slowly return not snap back. What little the current Starret wesite has on these is the above and accurate to .00005. They are in the foam lined metal box with red leather covering. The certificate and basic instructions were under the foam. Any one Have any info on these Mics?

There was also the assorted jack stands hold downs allen wrenches, clamps, and magnetic bases.

Any Infor on the 221 Mics will be greatly appretiated

[EDG]

The Starrett 221 is a premium cost mike intended for a higher resolution to 50 millionths (half a tenth) The spring loaded thimble is supposed to provide a more consistent pressure than just your sense of touch.
I began working with precision tools in 1968 and at all the shops I have been in I have never seen one.
The top mikes used in the most precision shops were the European type fat thimble types that are marked in .0005 (one half thousandths) hash marks. The vernier is more widely spaced since there are only 5 lines with this set up.
The top brands of this type are Etalon, Tesa and Mahr. Tesa and Etalon are different styles and brands made in the same Swiss factory. Mahr is a German made mike.
The Japanese Mitutoyo brand has a premium mike with a non rotating spindle.
I think the Etalon and Tesa mikes work the best for my skill and sense of touch. I like the big boat anchor Mahrs too but they are better suited for inspection using both hands where the worker is sitting.
I have the Mitutoyo non rotating spindle mikes too but the extra precision is wasted on me.
Without exception when any shop needed a higher level of precision we used a bench mike or a .00005 dial test indicator with a height mike or Cadillac gage. The next step would be the same indicator and a stack of gage blocks. Beyond that you can use a top quality jig bore machine to measure. Few inspection operations have the accuracy of a jig bore.

[EDG]

The Starrett 221 is a premium cost mike intended for a higher resolution to 50 millionths (half a tenth) The spring loaded thimble is supposed to provide a more consistent pressure than just your sense of touch.
I began working with precision tools in 1968 and at all the shops I have been in I have never seen one.
The top mikes used in the most precision shops were the European type fat thimble types that are marked in .0005 (one half thousandths) hash marks. The vernier is more widely spaced since there are only 5 lines with this set up.
The top brands of this type are Etalon, Tesa and Mahr. Tesa and Etalon are different styles and brands made in the same Swiss factory. Mahr is a German made mike.
The Japanese Mitutoyo brand has a premium mike with a non rotating spindle.
I think the Etalon and Tesa mikes work the best for my skill and sense of touch. I like the big boat anchor Mahrs too but they are better suited for inspection using both hands where the worker is sitting.
I have the Mitutoyo non rotating spindle mikes too but the extra precision is wasted on me.
Without exception when any shop needed a higher level of precision we used a bench mike or a .00005 dial test indicator with a height mike or Cadillac gage. The next step would be the same indicator and a stack of gage blocks. Beyond that you can use a top quality jig bore machine to measure. Few inspection operations have the accuracy of a jig bore.

This guy has a good bit of information for micrometer collectors.
I quit collecting once I got a nice example of the top quality mikes but I would never cough up the cash for the Starrett 221. They are a decent brand but cost too much for what you get. That is the Etalons and Tesas are more common at affordable prices.

https://www.google.com/url?sa=t&sour...bBJU56XX0wnVb2

[country gent]

I started in the trade around 1976. My personal mikes were brown and Sharpes for years. For gage work I had mititoyuo digitals These worked well for me. A lot of the shop measurements were made with a height gage and stacks of gage blocks. Mikes were routinely checked with gage blocks or pin gages at the mean dimension. Used like this mics are more comparator than measuring tool. In inspection they had several Coordinate measuring machines that did very accurate measurements. I wonder how many machinists, tool makers can do a precission layout on a granite plate and height gage today? I can remember spending a day or 2 with a inked up plate setting the scribe to gage blocks and laying out the part.