What is this rule used for

I cam across this rule n with a load of clock making tools, but suspect it got there by something unconnected ??

Its a plastic rule with 2 scales one in cm/mm and the other in inches and 1/16".

At one end is a clear plastic 'reticule' with a raised point in t5he centre. The reticule can rotate 360 degrees in the body of the rule. At the same end, the end of the rule is marked in degrees 0 - 75 in 15 degree increments. At the other end, there is a mark to indicate the centre line of the rule.

A clear lockable/sliding plastic cursor can be positioned up and down the scale and there are two "pencil point " holes that are 1" apart. By pressing down on the reticule and inserting a pencil in one of the hole, an arc can be swung once the cursor was locked in position.

By locating the reticule on to a point on a line, the rule can be swung to an angular position and a line drawn through its origin.

The maker was TRIMAN Ltd ref 1001

So what was its intended use ?

Something very similar is still on sale from Ajax Scientific and others, it's a ruler, compass and protractor all in one... Aimed at middle school children apparently...

search for TRIMAN OPAQUE RULER/COMPASS in your search engine of choice...

I guess it's American

Edited By Mark Simpson 1 on 15/08/2023 15:36:21

**LINK**

Product Features:

• You can draw circles, triangles and straight lines with this unique 4-in-1 drawing compass/ruler, construct, copy and read angles, measure and convert inches and centimeters, and create patterns
• To use the compass, pinch and slide the cursor to the desired position and lock it, place your finger on the transparent swivel disk, place your pencil point in one of the two cursor holes and draw a circle. Inch markings to 4.3″ (11 cm)
• Compass comes in solid opaque

that is that one solved - mental note - Must start drawing more triangles !

Thank you gents.

Given where you found it … I think it might be worth exploring whether it could be a convenient aid to sketching the layout of clock wheel trains.

MichaelG..

I used to have one of those when I was at school, may have just used it for geometry (maths) work.

I suppose these days it should be safer than a compass if not as good.