Mystery Measuring Stick

[steampunkpete]

Does anybody know for certain what this is?

I have a theory, but no certain knowledge.

There is a shallow slot on the back, and with the knurled clamping screw is clearly there to secure this mystery vernier to some other thingy.

[awemawson]

 ...dunno ... can't get it all on the screen at once to see it 

640 x 480 is a good size to post pictures 

[vtsteam]

Single jaw caliper.

These were sold on Ebay for years as compact measuring devices which only took up half the drawer space of conventional two jaw calipers.

[RobWilson]

Some bit of military kit for measuring the angle of the dangle   

Rob 

[awemawson]

Is it not a leaf sight from a rifle?

[Manxmodder]

I think Rob and Andrew are very close to the true identity. It looks very much like a sight to compensate for windage or projectile drop,possibly from a military rifle.

Here are a couple of links to similar devices fitted to rifles:
http://www.milsurps.com/images/imported/2011/03/DSC_0015-1.jpg

http://rifleman.org.uk/Images/bsamod12-15rs.jpg

.....OZ.

[Pete49]

No I don't think they have anything to do with a rifle peep sight. The arm is bevelled which leads me to thinking its a removable height adjustment gizmo possibly from a machine of some type or a centre height finder.
But then maybe not but I don't think its rifle equipment
Pete

[steampunkpete]

can't get it all on the screen at once to see it

Apologies. I have made the image smaller.

...  compact measuring devices which only took up half the drawer space of conventional two jaw calipers.

 

A part of a sighting device on a rifle - I can see where that comes from, but I'm not sure about how the bevelled arm would work.

So any more ideas?

[vtsteam]

Check the divisions -- what are they? mm, or not? And maybe the range -60-0-+60 holds a clue.

A sighting device might not necessarily use mm (or other standard) for divisions.

A measuring device surely would use a standard division spacing.

If it's a measuring device it was either fixed in place (slot in rear, retaining screw) and measured a relative height, or it had possibly a detachable second stop (or jaw) which could have been a standard length. Or it could be a device used to measure differences from a standard. Variations rather than an absolute measurement.

It would be helpful to see the back as well as the front.

[steampunkpete]

It would be helpful to see the back as well as the front.

Your wish is my command!

[vtsteam]

Looks kinda like a sliding stop.

[steampunkpete]

OK. Here are the clues that you have:

• It is marked with a broad arrow and is therefore government owned equipment.
• The nature of the mounting means that it was not intended for permanent installation, suggesting a calibration tool.
• A vernier - it's for making very fine adjustments.
• Not easy to see from the photo (without scaling from the 1p coin) the vernier scale does not map to imperial or metric linear measurements.

One possible clue you will not have, is that before he was transferred to the Intelligence Corps in WWII he was Royal Artillery (RA). In the RA he was assigned to heavy artillery batteries (4.7 and 6 inch guns). I found this amongst his effects.

My guess is that it is a calibration tool for gun laying equipment.

Any other ideas?

[RobWilson]

Some bit of military kit for measuring the angle of the dangle   

Rob

Scale is in degrees 

Rob

[DMIOM]

Scale is in degrees 

or minutes .... or seconds .....

and although some have suggested use on a rifle, I think it looks far too heavily constructed for routine use on a hand-carried weapon

Dave

[steampunkpete]

or minutes .... or seconds .....

I think measurement of angle is most likely.

Well, nobody has said anything that might suggest an application other than calibration of ordnance, so I feel a visit to the RA museum coming on.

Thanks chaps.

[DMIOM]

or minutes .... or seconds .....

I think measurement of angle is most likely.

Well, nobody has said anything that might suggest an application other than calibration of ordnance, so I feel a visit to the RA museum coming on.

Thanks chaps.

Minutes or seconds was in response to Rob's suggestion of degrees - 60 seconds in a minute, 60 minutes in a degree .....

Dave

[Bluechip]

If we're into artillery maybe we should consider milli-rads ???

http://en.wikipedia.org/wiki/Angular_mil

No particular interest, just fancied poking my sneck in .... 

Yet another ....

Dave

[awemawson]

Google this war office publication:

"Abridged Treatise On the Construction and Manufacture of Ordnance in the British Service"

It's available on line as an ebook or you can get a copy  - I'm sure that I have seen something very similar in that publication.

[vtsteam]

Scale markings shouldn't be regular spacing if it's angular on a flat, and vernier doesn't at all fit a non-regular division purpose either. Clearly bent arm is hardly ruggedized and one questions the need for vernier accuracy then, and the whole thing looks kinda low grade for what I think of as service quality.....

Nevertheless I believe best guess so far has been angular, and military, and sighting, cause things ain't always as they should be!  Naturally, just sayin' this to create additional confusion!   

[vtsteam]

It's part of a shoe sizer for military boots....

[steampunkpete]

Minutes or seconds was in response to Rob's suggestion of degrees - 60 seconds in a minute, 60 minutes in a degree .....

Understood - I was signifying agreement rather badly.

vtsteam makes a good point about the vernier appearing to be a linear scale in relation to a solution that one would instinctively expect to be non-linear. However, the gun might be subjected to calibration at a single fixed range, in which case a linear scale could / would be adequate.

A couple of things though: The quality of this thing (whatever it is) is excellent. In itself it is of adequate integrity to survive fitting to an artillery piece. What isn't rugged is it's mounting arrangement; it would not be suitable for a permanent attachment to anything in field conditions, hence my belief that it is for calibration only.

[awemawson]

If you look up that book I quoted they go into great detail regarding sight calibration, particularly in fixed locations. It was while reading up on the 'Palmerston Forts" that I came across it, as I wanted to know how they managed to sight fixed pieces that were behind often a natural earth berm so not in view of the target.

There are illustrations of attachments to the side and top of RML's (Rifled Muzzle Loaders) that probably are a forerunner of the device that you have

[S. Heslop]

I asked an artillery guy I knew if he recognized it, and he didn't, but said possibly part of a gunners quadrant (but doubtful).

Did a bit of searching on google image search and found this diagram.



From this website of a 'tangent backsight'.

It somewhat resembles the deflection adjustment on the left one.

Did alot more searching but I couldn't find a photo of the same device posted in this thread, but I don't think it'd require an aperture like a rifle sight since (as far as I know) when sighting artillery they line it up horizontally with posts driven into the ground.

[vtsteam]

I'm willing to believe it's a sight, but it raises a lot of interesting questions for me.

If it is a linear scale with vernier, and the angle is relatively small (minutes of arc) I can see that it might serve an angular purpose since a small range of angle approximates a linear scale better.

But that would mean that the entire range of the sight would be only plus or minus one degree, which seems like a very small angular range for a gun sight.

If it was degrees instead of minutes, then it really would be an inaccurate measurement if you impose a linear scale on an angular range of 120 degrees total (+60 to - 60)

If it is like the adjustment on a peep sight adjusmtent to bring it into conformance, a small (minute or second) amount of adjustment would make sense because it is in relation to a second sight point on the barrel, but isn't that usually "clicks"? in other words, relatively arbtrary. Why then would it be necessary to have an inconvenient numbering system like 60 instead of 50 unless it was important to relate it to an angular numbering system? The 30 mark and 60 range makes me think it is angular, but the range seems too be either too small, or too linear for sighting.

I'm sure there is an explanation, just curious how it works and why (as usual!).

[vtsteam]

Wouldn't a wide blade on top like that tend to block what you are aiming at to a dangerous degree? If there's movement laterally or behind, how can you tell?