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Anonymous Poster

How to Measure Length of Bent Object

12/11/2010 5:59 PM

Need help! Want to know how to measure the overall length of a bent object! Please someone help me! Radius, angle of bend and thickness of object is given. Using calipers-

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#1

Re: how to measure length of bent object

12/11/2010 6:06 PM

Take a piece of string, run along length of bent object, mark or cut at end, lay string out straight, measure, done.

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#2
In reply to #1

Re: how to measure length of bent object

12/11/2010 6:13 PM

No, that's too easy. He needs an excuse to go to the hardware store and buy a new, expensive tool.

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#3
In reply to #2

Re: how to measure length of bent object

12/11/2010 6:50 PM

thank you kramarat for your response - sounds good.

But, I'm working with tight tolerance of +/- .005". Does anyone know if there is any kind of formula I can use given angle, thickness, and bend radius. I don't know if I can hold tolerance with string.

Anyone?

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#7
In reply to #3

Re: how to measure length of bent object

12/11/2010 10:28 PM

Missing details needed to give a great answer but if it is something smaller than say ones hand an optical comparator or a cmm are possibilities for measuring.

http://www.toolingu.com/definition-350110-1996-optical-comparator.html

Milo

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#4

Re: how to measure length of bent object

12/11/2010 6:58 PM

(Pasting from my reply to the dupe thread):

For the bend part, pi x radius x angle(°) ÷ 180.
For the straight parts, their individual lengths.
Add them all up.

That's how to calculate it. To measure it, use a tape.

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#5
In reply to #4

Re: how to measure length of bent object

12/11/2010 7:11 PM

That sounds too easy too. I guess measuring it before it was bent is out of the question also.

I wonder if there's some kind of medical software, where he could take an x ray and get an exact calculation of length.

Or find somebody with one of these.

http://www.melsensor.de/laser-scanner-m2ilan2-en.html

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#6

Re: how to measure length of bent object

12/11/2010 7:38 PM

"Radius, angle of bend and thickness of object is given."

Given to whom?

Is this sheet metal, pipe/tube, other structural shape(s), or what; and what material?

After the item is bent, it will spring back about 2-3°, so the inside radius will not perfectly conform to the die nose, shoe, mandrel, or whatever.

One way to go about this is to measure a prototype carefully before and after, and then adjust the real goodie accordingly.

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#8

Re: how to measure length of bent object

12/11/2010 10:51 PM

"Using calipers" seems to indicate that this is a smallish item.

What is the purpose of the exercise?

If this is a bent pipe or rod - what about put the smallish object on a scale and divide by the weight per unit length of the class of pipe / rod used? (and reproduce and test the part.)

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#9

Re: how to measure length of bent object

12/11/2010 11:15 PM

Weigh it

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#10

Re: how to measure length of bent object

12/12/2010 8:33 AM

The problem with your question is that not enough information is provided. Consider the bent rod in the sketch below. Which of the 5 lengths shown, A through E, is the one you wish to measure? Each one will give you a different value. Or is there yet a different length you are interested in? A picture of what you are trying to measure would be helpful.

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