Author Topic: Old School Triangulator  (Read 727 times)

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Online ScottieMTopic starter

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Old School Triangulator
« on: Apr 16, 2024, 17:32:49 PM »
I was trying to remember what this was called last night, and maybe there's some old school tin knockers still out there.
Before plasma tables we had to make cut lists for all our duct to be cut on the shear. There was a triangulator (?) I used to use that to figure the hypotenuse for transitions and offsets without having to use a calculator.
It was a quart circle or 1/4 pie shaped with a slide rule that was mounted to the radius point. You could pick the length, the offset and it would give you the hypotenuse or line development length. Most of the sheet metal companies used to have them for free. I tried looking up one for sale but couldn't remember what they were called. Does anyone remember.

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Offline cadbob

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Re: Old School Triangulator
« Reply #1 on: Apr 17, 2024, 15:34:16 PM »
I'll Bite! lol   A Protractor?

Oh forgot to mention some people call them Angle Finder
« Last Edit: Apr 17, 2024, 17:03:57 PM by cadbob »
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Online ScottieMTopic starter

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Re: Old School Triangulator
« Reply #2 on: Apr 19, 2024, 12:29:43 PM »
Thanks, but that's not it. I'm feeling nostalgic and was wondering if I could find one for purchase somewhere.
It was a tool almost like a slide rule, but for hypotenuses specifically, for the sheet metal trade.
My has the industry changed in 40 years. I wonder what it will be in another 40.

A back story for the interested.
We're a mechanical contractor that does commercial and industrial work. We do sheet metal, pipe, plumbing, electrical, fire protection, and structural steel. We have all the toys a shop could want and automated as much as we can do. But every now and then, something comes in that a computer program can't figure it out. Having served a 4 year apprenticeship in the early/mid 80's, worked in the field and became a shop layout guy, I'm often the one figuring out the cut patterns to be put in the CAM station for fabrication. I teach as the work is done, trying to pass some of the knowledge along. When I explain plasma tables basically didn't exist and everything had to be figured out manually, mostly without calculators, people wonder how that was even possible.
So I was wanting to buy one of these things(?) and show how we used to figure our cut lists.
Scott M.
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Offline Axl

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Re: Old School Triangulator
« Reply #3 on: Apr 19, 2024, 13:10:50 PM »
I learned how to use the sliding rule back in 1985, maybe you are looking for a circular version of such?

https://en.wikipedia.org/wiki/Slide_rule#/media/File:Circular_slide_rule.JPG
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Online ScottieMTopic starter

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Re: Old School Triangulator
« Reply #4 on: Apr 19, 2024, 20:18:41 PM »
The idea is getting closer. I hope I can find one now so I can post a picture of it.
It only solved hypotenuse lengths.
This is from old memory, it was quarter pir shaped. I think it had wavey lines that were numbered within the body of the pie shape. The arm was numbered along its length. You would match up one side of the triangle to the body number and the other side of the triangle to the are number, and along the outer edge wherever the arm landed would be the hypotenuse length. 
Example: 9 inch offset and a 9 inch rise, and the arm along the outer edge would be near 12.7
This may be a little clearer of what it looked like and functioned.
Scott M.
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