Layout tool

Hi, I was given a box of old tools. Along with the dross I found a few intriguing items. A couple of 2 ft casting rulers- 1/48, 1/72, 1/96 which have built in shrinkage allowance. And this brass ‘Protractor’. Could anyone suggest what it may have been used for, or who might have used it in their work?

Edited By Mike Armitage on 01/06/2022 15:54:52

Edited By Mike Armitage on 01/06/2022 15:59:23

what brass protractor ?

Twice I’ve edited to add photo! Soon

Marking angles, drawing circles of various diameters, marking out gons, and likely several other useful shapes and curves?

It has a patent number which you may be able to find.

An interesting item.

Interesting find: there's one in the Victoria and Albert Museum! Their description here. Note the front page of the manual and the example page from it, bottom right. I've always wondered how the Victorians did those elaborate patterns.

Don't think it's valuable - there's one for sale in the US for $59 dollars.

Dave

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Undisclosed on the instrument

But here we go: **LINK**

https://worldwide.espacenet.com/patent/search?q=pn%3DUS332148A

MichaelG.

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Downloadable via the three-dot menu at top-right of that page

Edited By Michael Gilligan on 01/06/2022 17:17:35

Aah, so an early version of Spirograph! Wonder if I can get a copy of instructions from V&A?

It seems closely associated with a similar item, called a geometrigraph.

The difficulty with searching for polygraph is that the word is also used for a lie detector test.

Lee Valley Tools sells a reproduction:

https://www.leevalley.com/en-gb/shop/home/toys-and-games/arts/68730-geometrigraph-and-polygraph-set?item=09A0155

The box of old tools were probably used by a pattern maker. The brass protractor is a multi-purpose tool for marking out angles, curves, squares, etc. Concentric circles drawn by placing a pin in the centre hole and a pencil point in one of the small holes and using it like a drawing compass.

Similar plastic tools were used in the drawing office when we used boards for drawing, circles, arcs, ovals, etc.

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MichaelG.

This is from the patent:

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Anyone fancy producing a Vector file, so we can all play with it ?

MichaelG.

This article describes it as not just for designers and drafters but more as a child's toy. Made from brass before the use of plastics became available.

Thanks Guys for all that info. It seems that I have found the wonder of the age!

You can still buy them apparently:-

*** Lee Valley *** Canada $15.95

John

You have, Mike!

It is a wonderful device - perhaps a potential fun project as a break from the intricacies of a full model-engineering project?

Those with CAD/CAM equipment might find it an interesting challenge. Without, it might lend itself to being profiled and having the lines engraved, on a jig-borer. Or indeed, a neat hand-work exercise. The degree calibrations would guide setting-out the holes. The originals were probably in sheet-brass but if still made a few decades later, no doubt it would have exploited the transparency of Celluloid.

And may yours too gain "the highest awards at various exhibitions" - though I am not sure of its category!

I've sometimes thought that perhaps in the Clocks and Scientific Instruments, and Tool-making, categories of model-engineering, some of the ingenious but long-surpassed or take-for-granted things patented in the late 19th - early 20th Centuries could be worth exploring. Some of the tooling tips in early editions of ME bear re-examining too, perhaps up-dating; but I don't go as far as how to re-cut a domestic tap seating on the lathe! (In that example, the writer only made a basic Keats angle-plate anyway.)

Paul -

I see what you mean. It is clear the makers originally intended children to use it as an educational aid to learning geometry, as well as an inspiring artistic toy. This is further amplified by the page Michael shows us, from the " ... And Export Journal" that states it was aimed mainly at children - oh, and ladies - but professional designers and artists also use it. Useful too, giving some idea of how to use it.

That reference also reviews what we now know as a wall-planner or week-to-view diary. I didn't know those date back to the 1880s. Made by "Acme" , a name so often used in fun as a fictitious maker of goodness-knows-what; but any relation to the "Acme" famous for the "Acme Thunderer" referee's whistle?

Plus an "Envelope Moistener" , a more elaborate precursor of what became so familiar to many of us, on the proper bank and Post Office counter.

Whilst the accompanying "Draftsman's Compasses " - was the journal, American? - is intriguing, and the complicated description would be far clearer if accompanied by a drawing.

Hmm, shrinkage; as an apprentice I was working in the glass shop cutting glass for customers.
A gentleman came in with the usual bit of paper clutched in his hand and asked for a bit of picture glass which I cut, wrapped in newspaper and duly charged him for (all cash was handled in the office).
An hour later he was back, "you cut this wrong! it's too small".
I fished his paper from the tea chest we used as a bin and checked my size, all correct.
He went off in a huff. Another hour passed, the gentleman returned, this time clutching a fine boxwood and brass rule (you can see where this is going).
"I have been using this rule for 40 years, never had a problem" he proclaimed.
I offered it against the rule I had used to cut his glass and lo! the marks did not correspond. Upon closer inspection we discovered the legend "Shrinkage of Clay" embossed by the makers lozenge on his rule. He was correct, it had worked well in his shed but he'd never had to buy glass before.
He threw it on my bench and said, "You can keep that, I shall buy a standard rule".
and so for years it hung on the wall ready to wind up the unsuspecting, it now resides in my shed.

Set of instructions for a slightly later version here:

https://linealis.org/wp-content/uploads/2017/03/Polygraph.pdf

Fairly detailed write up with some actual measurements here:

http://sliderules.lovett.com/ARTICLES/SKID/SS43.pdf (The slide rule society)

Edited By DC31k on 03/06/2022 09:59:32

Thanks for that DC31k

If you zoom in on the bottom left quadrant of the photo, it says 'improvements patented in Europe Dec 1885'.

Is it possible to find that one?