Long time lurker first time poster, a bit about me I am a college student studying ME at Virginia Tech and love riding, this is my first jump into the framebuilding world. Name is Abraham Shipley to help be compliant with the rules.

I have mostly copied this from some plans I found online. Still in process of working on finishing it up and will likely be making a few more changes before I am happy with it. Right now the main beam is a 120x40 extrusion, vertical beam 80x40. When I go to build the jig (and will be changing the model/making a new one) I will end up using a 160x80 main beam and 80x80 vertical beam. I plan to use Item extrusions as they are local and have been very helpful along the way (plus they offer a student discount which is a nice benefit).

I am still working on trying to add purge fittings as well as the bottom bracket mount. The first question I've got is for the purge fittings, where exactly does the air bleed out? I know that we don't necessarily want to "pressurize" the tubing, just fill it with the argon to prevent contamination. If I add a purge fitting to the HT cone for example where would the bleed be for this? Or is it safe to assume the joints will never so close to create an air tight seal?

For the ST extrusion, the way it sits is two pins that pivot along an arc with the single handle tightening/clamping to lock the angle. Is this single handle enough? It is M8 threads I believe.

I don't plan on making a lot of frames, probably just a few for myself and some friends. Really doing this jig to make the process easier and I've got access to the necessary machines to make all the machined components. Before making the L-brackets that hold the cones, I would likely lay the two main beams on a friends alignment table and get some height measurements along the extrusion to help calculate how much offset I need for each of the different locations. I don't think I want to slot these brackets as it would just make alignment that much more difficult (better to limit the numbers of DOF right?)

I have not yet worked out what to use for my own personal alignment table, was leaning towards maybe looking into a granite surface plate or granite counter top and using that with V-blocks/a BB post...

If you've got any thoughts on the design I'd be happy to hear it