Re: Re: Rubber cross-section

From: Phedon Tsiknopoulos <phedon21t_at_yahoo.com>
Date: Tue, 17 Sep 2013 18:11:23 -0700

So the weight determines the final length, am I right?

Sent from my iPhone

On Sep 17, 2013, at 12:08 PM, <leop_at_lyradev.com> wrote:

> Gary,
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> For my F1D and F1L motors, I get a precision of 0.05" in length for total motors weights of 600mg and 1000mg respectively. My tolerance on weight for these classes is 3mg (plus and minus added) as that is the weight of one half of a knot.
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> I, too, make test cuts on short pieces of lesser quality rubber before striping the good stuff. It often takes me more than three test cuts to get things right.
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> Leo (aka LeoP)
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> --- In Indoor_Construction_at_yahoogroups.com, <indoor_construction_at_yahoogroups.com> wrote:
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> Bill, Mike or anyone,
> But the catch-22 is that first you must accurately measure the width of the strip, then accurately set your slicer to cut a specific width in order to end up with a specific weight loop!
> For the sake of this discussion, assume there is no max. motor weight requirement & you wanted a loop weight of 1 gram, what tolerance would you consider acceptable?
> How many test cuts do you usually need when trying to cut a new width strip? I would say it typically takes me at least 3 short test strips.
> Gary H
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> From: William Gowen wdgowen_at_...
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> So you calculate the density of your 1/8" rubber and then calculate the strip width based on the density. I rest my case.
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> On 9/17/2013 10:50 AM, mkirda_at_... wrote:
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>> Here is an example for F1L.
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>> Find the loop length that you want. Cut a bit of rubber to be the length plus 2 inches.
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>> i.e. 14" loop, cut (14+1)*2 = 30 inch length = 15" doubled.
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>> Measure the width of the rubber with micrometer - i.e. 0.128"
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>> Weigh the length of rubber. i.e. 2.54 grams.
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>> You decide you want the rubber to weight 1 gram exactly.
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>> Here is the math:
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>> 1/2.54 * (15/14) * 0.128 = .05399
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>> Strip it to 0.054" and you when you tie off a 14" loop it should be precisely 1 gram.
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>> I set up the spreadsheet to have only 1" additional length, but the math above is the same.
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>> If anyone has problems with this, I will define variables and post the math that way.
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>> Regards.
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>> Mike Kirda
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Received on Tue Sep 17 2013 - 18:11:26 CEST