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80/20 Frame Jig Build - which size of the bottom rail is appropiate?

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80/20 Frame Jig Build - which size of the bottom rail is appropiate?

Old 09-14-23, 03:47 PM
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apollodriver
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80/20 Frame Jig Build - which size of the bottom rail is appropiate?

hello dear all

i currently work on a jig that is build according the Tanner W - manual: see https://www.instructables.com/Bicycl...-Building-Jig/

the question: which bottom rail does he use:

160 / 40 or
160 / 80
... thats the question! ... see here: https://www.instructables.com/Bicycl...-Building-Jig/

well - it seems a bit confusing

see the question in the thread... https://www.instructables.com/Bicycl...-Building-Jig/

metalmicky7 years ago:
Hey Tanner, great post. I've begun my build following your instructions. Is there a mistake in your extrusion materials diagram however? You mention using 160 x 80 in your description on page two. But in your materials list you have a length of 160 x 40...??

Tanner answered
160 x 80.

Well - what do you say.

see the bottom rail

see the bottom rail more insights

see the bottom rail - see more detials

images all taken form the instructable - https://www.instructables.com/Bicycl...-Building-Jig/

see the bottom rail - well what do you say - Tanner uses various declarations and measures

should i take the
160 x 80. or the
160 x 40


by the way: see also the intersting threas: 80/20 Frame Jig Build Thread
https://www.mtbr.com/threads/80-20-f...thread.991932/

the author (seahuston) discusses his approach ... and i think that he shows that a smaller bottom rail is used in his "approach" -

seahuston tells the following:
I decided to build the majority of my jig using 80/20 brand extrusions. There are a variety of aluminum extrusions available, Arctos jigs use Item brand extrusions.
Because many bicycle dimensions are given in metric, and I think it is a better system, I went with Metric extrusions. I went with the 40 series metric extrusions.
A little information I learned about 80/20:
80/20 comes in a variety of metric and SAE sizes. Their naming system give the distance between channels on all extrusions in that series. For example metric 40 series is 40mm between channels and the 1.5 series (the approx. metric equivalent to the 40 series) is 1.5 inches between channels. The individual extrusion options are named for their dimensions. 40-40 (the skinniest option in the 40 series) is 40mm x 40mm. It has one channel in the center of each face (20mm from each side). The 80-40 series is 40mm x 80mm. The 80mm face has two channels and the 40mm face has one channel. Each extrusion series is designed to use a specific hardware. 40 series is made for M8 bolts. The channels take M8 bolts and the end holes are the right diameter to be tapped for M8 threading. Therefor I used almost exclusively M8 bolts for this project. Detailed CAD drawings of lots of the available 80/20 extrusions can be found on McMaster Carr. However, McMaster did not have all the specific extrusions that I wanted so I ordered all of my 80/20 on Amazon.
see https://www.mtbr.com/threads/80-20-f...thread.991932/

see the many images in the thread - and the bottom-rail: https://www.mtbr.com/threads/80-20-f...thread.991932/

well what would you use!?

what do you say!?
what would you choose!?

Last edited by apollodriver; 09-14-23 at 03:57 PM.
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Old 09-15-23, 12:23 PM
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unterhausen
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160x80 sounds like a good idea to me. I suggest not overthinking it though. The 160x40 is probably fine if you want to use that. I'm using a piece of extrusion for a different purpose that's about that wide and it seems plenty beefy.

I like Misumi extrusions. They do a really nice job of cutting it square and to your desired length. I'll admit their website is a bit clunky.
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Old 09-16-23, 02:07 AM
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apollodriver
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dear Unterhausen

many thanks for the reply and for sharing your ideas / insights and thoughts

Originally Posted by unterhausen
160x80 sounds like a good idea to me. I suggest not overthinking it though. The 160x40 is probably fine if you want to use that. I'm using a piece of extrusion for a different purpose that's about that wide and it seems plenty beefy.

I like Misumi extrusions. They do a really nice job of cutting it square and to your desired length. I'll admit their website is a bit clunky.

thank you very much. I am glad to be part of tihis great & awesome forum

have a great day
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Old 09-17-23, 10:25 PM
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Agree, you're probably overthinking it a bit. I believe my beam is the 160 x 80 range and I don't worry about flex/deflection or anything. On the downside, It's a bit bulky and heavy. I believe my beam is 1200mm and the head tube upright is 750mm or longer. I generally use less than 75% of that range for even long touring bikes.
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