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1890s digital micrometer

Asquith

Diamond
Joined
Mar 3, 2005
Location
Somerset, UK
Dscn1281.jpg


Early digital ½“ micrometer. Maker: Ciceri Smith, Edinburgh, 1890s. Divisions on thimble allows reading to 0.0001”.

Ciceri Smith made wire mesh, and wanted his workers to be able to measure diameters quickly and accurately, so he invented this digital micrometer. Just like that.
 
Asquith,
That is a dandy little gem. In the U.S. I thought J.T. Slocumb was the originator of digital but yours predates that by decades. Thanks for sharing.
By the way, I noticed your scale....you folks still allowed to play with fractions and inches on that side of the pond? :D
 
These are pretty neat....... I have some of them but I think they are all marked London.... Mr. Smith was from Scotland so this could be earlier than mine. He was in the wire business and came up with this to help his guys in the shop as I recall reading...... in my attic I have a whole file on him. The American firm of Brown & Sharpe bought the rights to his patent but did produce they're own till some years later.... it may have been to block them from the US market.

What I would like to find is one of his early style ones like the one pictured below...... it is the one sent to the US patent office as a model and is in storage at the Smithsonian.... it has windows at the top.....

Did you get this at the David Stanley auction in March? they had three of them, 2 in cases and they did very well.......As I'm sure you know they made many variations of these.... I forget how many models, I think it was around 10 or 12..... one of mine is the rare 4 window.... it has a 4th window under the .001 with a 0-5-0 for half thousandths...... and Ciceri was not the only of your country men to make a digital mic in the 1890's..... Grimshaw & Baxter also did one of which I own only a half of...... so if anyone has a mic with a worm gear cut on the thimble.... I WANT IT!!!!!
cicerimic.jpg
 
Rivett,

The micrometer in the photo you posted certainly seems to have sneaked past the duty ergonomicist!

The Ciceri Smith mic was my father's, but I don't know its earlier history. I also inherited a very nicely-made Brown & Sharpe #30 0-2" mic. I never saw him using them - his everyday mics were Moore & Wrights.

I seem to have been bitten by the small hand tool bug, partly following your advice about owning antiquities that are portable. Another thing that really kicked me off was the pliers/vice/vise whose picture I posted elsewhere, which may be of considerable age. It's made me realise that we've lost something along the way in terms of the ability to make superb quality tools with relatively primitive equipment.
 
"I seem to have been bitten by the small hand tool bug"..... you know this can be fatal so watch out......

It has always amazed me what kind of work these folks of the pass time did.... and so much of it with files.... I keep these things around on my workbench so just about the time I think I am doing some good work I look at this old stuff and remember..... a lot of comes (like your tongs) from cottage industries.... in other words made with help from the kids and by candle light..... kind of puts me in my place.

I know you will not sell your father's mic, and shouldn't, but just for fun.... what do you think it is worth? don't cheat by looking up the price.... just guess and in a while I'll post what they sold for in March..... and others can guess too....
 
Rivett,

I couldn't hazard a guess at the price, but I think my brother will be more shocked than I when you reveal it. You see, the other day I asked if I could borrow the mic to take a photo of it, and he said I could have it.
As you say, I won't sell it though.
 
Asquith If your brother reads this he just may be a little pissed..... This is from the David Stanley sale on march 25 2005 in Leices......

Lot 1210 A rare brass CICERI SMITH Patent Micrometer with Decimal Parts of an Inch in orig. fitted case with spanner. G+ £500 / $965
45-1210.jpg


also lot 1211 a 2 1/4" (little 2 window metric) one # 17 "Ciceri Met" for 360 pounds or $695. and lot 1212 a 3 1/4" (1/2" 2 window) for 360 pounds.... both in cases as above.... and there was a 10% buyers premium + VAT added....... so these are not so cheap any more....... what are you going tell your brother now? you should at least buy him a pint.....
 
Ok, I'll venture a guess at a round $1000.00. No doubt to Asquith the value is priceless, as well it should be. I have an old polish 0-1" mic my Grandfather left me, real value $5, to me its priceless.
 
:eek:
On second thoughts, :eek: :eek:

I've told my brother, and he wasn't at all perturbed. He's like that. I will buy him a pint, and I might even give him my old Bakelite Avometer. It might be worth something in a hundred years.
 
I was just reading the USA patent about the Ciceri Smith digital micrometer. It is patent # 1444565, on Google Patents here:

SMITH - Google Patent Search

I am finding several curiosities about the patent.

First, it was filed on Sept 1, 1920 and didn't receive the patent on Feb 6, 1923 - 2 years and 4 months later.

Second, a Ciceri Smith digital device was patented elsewhere (UK) in 1893 - 27 years before!

Third, the USA patent itself is 8 pages long. I have seen many patent papers that are only two pages - a drawing and a single page claim description. 8 pages is very word heavy. And, it could explain the delay between filing and granting of the patent.

I have been trying to understand the 5 pages of claims (there are three pages of drawings), but reading patents is a foreign language I have not mastered - English language words in non-English language phrases!

Maybe Asquith can help me out by pointing out the UK patent for the Ciceri Smith micrometer?

Right now, I'm guessing that the original UK patent was for the early, round tube with digits on top version that Rivett shows in an earlier post here?????? And the 1923 patent is for the flat version most of us collector have?????

Someone, please set me straight!

:cheers:
 
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Asquith, in your description in the original post you say it measures to ten-thousandths of an inch. Is that a typo or is it read off the vernier on the thimble?

(I can see putting the tenths vernier on for occasional precision use, but not finding it necessary to include in the digital dials, which is why I ask.)
 
That patent (1444565) is interesting :

He uses elliptical gears to remove backlash and to accelerate the digits as they change.

He has a collet to allow the gears to be adjusted (synchronised) to the spindle and to each other, so that Metric & Inch (simultaneously) and/or Fractions can be displayed and 'zeroed' correctly

There's a dual direction ratchet (or clutch) on the thimble to prevent over straining the gears or thread.

He suggests the use of either a normal (50tpi or 0.5mm pitch) thread or a non-direct reading thread (presumably so the two gear chains can be symmetrical - to make the gear box layout easier perhaps? ) and an usual (and not yet completely understood, by me) helical compensator to convert and adjust the spindle motion to the Inch and Metric counters. (essentially it twists the Metric gears a little further if using a 50tpi thread (i.e. 25 turns [1/2"] are counted as 25.4 [half turns] = 12.7 mm on the dials )

Bill Todd

The earlier patent is here : http://www.google.com/patents?id=NW...=onepage&q=j ciceri smith micrometer&f=false
The action of the helical compensator is a little clearer in fig19
 
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WOW, that blows my mind!

That is officially one of the coolest things I've ever seen. I knew it was possible, but didn't think the people of that time thought that way. This is one of those things that might take a while to sink into my brain. :cheers:
 
This five year old thread has brought me out of retirement.

I’ve been looking again at my micrometer, shown in post #1. In response to fciron’s question, I can confirm that the vernier allows 0.0001" readings to be made.

Obviously the accuracy of reading a micrometer to tenths of thous depends on applying a consistent amount of force to the thimble. On this mic, the sleeve is in two pieces, so I suspect it might have a friction drive arrangement. However, it is tight, and the screw on the end of the thimble is corroded, and I don’t want to try adjusting it.

There is a small zero error (0.0001") which I could adjust out on the screwed anvil, but as I’m not going to use it in anger, I won’t. However, I did a calibration check using slip gauges (Jo blocks), at 0.1" increments up to 0.5", taking great care to apply the same torque each time. The readings are spot on (allowing for the zero error - i.e. every reading is dead nuts minus 0.0001").

The micrometer is beautifully designed and made. It is stamped No. 86, and there’s a very faint etched symbol - a crown and 'VR', showing that it must have belonged to a government department, before 1901 (Queen Victoria died in January 1901).
 








 
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