Micrometer w/ two thimbles... one for .0001"

rivett608 · Oct 20, 2005

Do any of you that don't have one of these know how it works?..... looking in the catalog is considered cheating...... Any way this was one of many tool ideas that to someone seemed like a good idea at the time but due to the fact they weren't made for very long shows the users did much care for them........ it is a B & S #24 RS.... with a separate thimble to measure tenths...... made just before WWII..... and they made it in a bench version, the # 240 RS...... these are pretty rare and they must not have made many because instead of printing a label for the bow they just typed out the number on a blank one.......

JimK · Oct 20, 2005

The little spindle is on an eccentric. Turning it swings the main barrel.

The graduations on the little thimble tell how many tenths it takes to line up the graduation on the main thinble with the line on the barrel, thus splitting the thousandth graduations into ten parts.

Peter S · Oct 20, 2005

I guess that means that you have to 'zero' the little dial each time you use it?

If not,you would be making a bad reading on the main dial.

My first reaction was that it is a neat idea - I just like to see all the ideas that people have come up with.

On second thoughts, being pretty forgetful, I can see myself gettting into trouble with that mike!

Asquith · Oct 21, 2005

Rivett,

Thanks for showing it to us.
I thought along the same lines as Jim, but that and all the other lines I thought of seemed to lead to trouble. Having used it, what do you think about its practicality and reliability?
Does the fact that the small thimble has a screw in the end suggest that it contains a ratchet? If so, that seems to be at odds with Jim's suggested modus operandiiiii.

rivett608 · Oct 21, 2005

JimK is right again...... you do have to zero the little thimble each time and it does not have a rachet....... as to use?... I don't know as I have never even used these

Does any one out there use them or has in the past?... or ever even seen one?

smallshop · Oct 25, 2005

Rivett,

I notice your wood grain is back to normal size again.

hms50 · Oct 25, 2005

The only one I've seen was on the bay. I tried to buy it but somone wanted it more than me. I would be interested in a review of how practical the system is and if it is prone to give "bad" readings because of the need to re-zero. Somday, I would like to have one for my collection just because it's neat!
hms50

JimK · Oct 25, 2005

I like the idea a lot. I think the tenths are easier to read.

Depending on how good the bearings are, simply lining the little thimble up with it's zero, gets the make back to it's normal calibration. Yes, you have to remember to do that.

Swinging the main barel does not introduce back lash like moving a screw thread one way and then another does. The little thimble doesn't need a rachet, it is not feel dependent since it doesn't move the measuring screw thread.

The illustration of the bench micrometer makes me think that this kind of mike arrangement was primarily for the inspection department and not for everyday use on the shop floor.

rivett608 · Oct 25, 2005

Jim K I can't tell from your comments if you have used these or not? If so you would be the only one I know of who has which is pretty cool as most of my stuff is so old that few still around remember it in use..... the fit and finish is quite well and there seems to be a lot of bearing area to keep the thimble tight. The only problem I have seen with these and it might be because I suspect these examples have been sitting around unused for about 50 years is the oil dries out and sticks the thimble in place and then someone tries to force it to work and bends/breaks the cam lever.... so if you find one and it is tight give it a good soak in lacquer thinner..... B & S and others made a number of their micrometers in bench models... on the same page in the catalog is the # 243.... about the same less second thimble and with a lock.... I have another B & S bench mic that I think is a factory prototype.... it has yet to be seen in any catalog etc.... some day I'll have to post it....

Hms50 "Somday, I would like to have one for my collection just because it's neat!" my kind of guy!!!!

JimK · Oct 25, 2005

Rivett:

No, I haven't used one, nor have I even seen one until you posted your pic.

I am ugly and my mother dresses me funny, but I can read machinery almost as if I had a sixth sense.

jkilroy · Oct 26, 2005

"Somday, I would like to have one for my collection just because it's neat!"

Damn right, thats what collections are for! Same thing I tell people when I roll in another 3 ton piece of old iron.

rivett608 · Feb 21, 2007

Bump.... anybody find one yet?

fen2art · Feb 22, 2007

Still looking (or would that be dreaming?)

Phil

Mic addict · Feb 23, 2007

fen2art
Just keep hawking ebay. Ive only seen 1 in the years I've been doing it but they ARE out there.

blackboat · Feb 23, 2007

Oh great, I missed this on the first go around, but now I find another neat gadget to kep an eye out for.

Maybe this old post bumping isn't such a good idea...

Rob

Nathan Flycutter · Feb 23, 2007

I like it!
Edit: The idea I mean.

rivett608 · Jan 21, 2019

Pictures of my two spindle mics. In this thread.

rivett608 · Jul 30, 2020

I see one of these just sold for $622. On eBay last night. Good to see there are still collectors out there that desire the rare objects. In all my years of collecting I have only seen a few of these.

Anyone here get it and want to fess up?

Froneck · Jul 30, 2020

Very interesting Mic. I don't think the second spindle is intended to measure tenths as it would if it had a .0000 vernier. Seems to me it would be difficult to use. It would require taking a measurement, if reading was not exactly .000 increase it to he next .000 then measure again using the second spindle and subtract the reading? I could be wrong since I've never seen one nor have any idea how to use it. I'll be watching this thread to see if someone that has used it for it's intended purpose responds.

jwearing · Jul 30, 2020

I was just speculating on this in the other thread. Rare unusual b&s #24 dual adjust knobs micrometer ebay

I think the tenths dial has an eccentric that moves an arm, that rotates the barrel under the main thimble. If that's right it's quite a nice design.

Micrometer w/ two thimbles... one for .0001"

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