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Perimeter jig design.

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I built this a while back when I was looking at small scale manufacturing of frames, but I hit so many obstacles obtaining the right materials that the manufacturing never happened, however the jig works great and I figured it should be shared here for anyone who is looking to build one.

It is oversized to allow for whatever designs may happen in the future, barely fits on my workbench and it pretty weighty! Sat Back40 in it to give a size reference:

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The two uprights are welded on the diagonal:

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I will explain why once I get the pieces made that mount to them.

Then I moved on the bottom bracket clamp:

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Lots of steel there to draw heat away, they will bolt to the jig and then a big 9/16 bolt will bolt through the whole clamp as well.

Lots of thought is going into this jig, hopefully I have allowed for almost any design that may happen in the future... :thumbsup:

Added some locating plates to the BB mount:

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Simple dropout mount, width adjustments can be done with locknuts or washers, still need to drill bolt holes to lock it to the jig:

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It will bolt to that diamond upright there which will make sure it is always straight and true to the base, that is why I welded the end supports in the diamond position.

Also made a fork dropout holder, pretty similar but mounted from the base, can be slid along the base and bolted at any distance, and also has height adjustment with a wing bolt, still need to drill the bolt holes in it too:

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Lots of hole drilling and tapping threads today.

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That is as far as I have taken it, I was planning on bolt on mounts that would hold the top of the seat tube and the fork top, for building multiples of the same bike it would be handy, but for one-off builds using recycled parts I found it unnecessary, the forks hold the headtube in the right place and I just trim everything of the recycled bottom bracket except for the seat tube, once it is in the jig it is basically a matter of connecting the dots.

You could make a smaller and lighter version by removing the top bar and the upright at the front of the frame if you are making it for one-off builds, I will keep mine as a full perimeter set up in case I decide to pursue manufacturing again.

Luke.
 

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