Framebuilders - Pinning

Hello,
I have built a few lugged frames which seem pretty good, but I am unclear about pinning. I have been using a homemade jig, and have not been pinning at all.

Is there something I am missing? A lot of the good builders use pinning, but I don't really understand what it does. When should I be pinning?

Thanks in advance

Pinning thread (http://www.bikeforums.net/showthread.php?t=485845)..

The "Search" function is your friend. ;)

OK, so because I have a jig and an alignment table I don't really need to pin?

OK, so because I have a jig and an alignment table I don't really need to pin?no

Thanks very helpful.

When exactly should I use pins, and why do I need them when I am using a jig?

Nevermind, the search function is indeed very helpful!

Sorry, I was busy.

Just to recap, a jig probably cannot withstand the stresses you will be putting the frame under when you build. If the jig could withstand these stresses, the tubing may not be able to do so. Either way, you may end up with a frame out of alignment. A bad thing all 'round. Thus most builders pin and tack, and then remove from the jig.

Its all good, thank you.
I have been tacking in my jig, then doing the rest of the brazing in a stand, but not pinning. Then I align it afterward on my alignment table. But I haven't been pinning, could pinning potentially help me on any way?

If you are getting straight frames out of your technique, then I see no reason to change. Is there some reason you would like to change?

No. I thought maybe I was missing something or didn't understand something.

Pinning seems to be a newish fad (not a new technique). Been reading older books and they don't report a lot of pining or a lot a jigs. Both these seem to be modern crutches, not as modern as CNC MIG, however. :) Someone moving fast, but largely by hand wouldn't necesarilly want to pin if they could control the process without. It's more stuff to do. Some top builders today like to do it, as in the past. No one right way. Paternek does mention pining forks is worth doing, that the jig alone may not control the potential movement.

Bicycle Guide featured Richard Sachs in a June, 1990 cover article, "The Art of the Framebuilder." Richard discussed pinning and why he does it in the article. I have the seven page article as a 1.7 MB pdf file and would be happy to e-mail it to anyone that's interested. PM me with your e-mail address if you'd like a copy.

http://i32.photobucket.com/albums/d7/k4drd/Bicycles/Richard%20Sachs/Coversm.jpg