Topic: '73 500 - Subframe Fabrication

[calj737]

With a frame like that you can support 2-3 ton on top? (Swag)
very nice and tidy work area...where did you learn all your skills Cal?
You are a veritable jackass

Well the tubes when multiplied (walls) are 1" thick steel. That will hold way more than I'll ever load onto it. Tube steel in that orientation is wicked strong, so I don't envision any issues whatsoever. The top is 5/8" so it's pretty stable, even with the holes. They're 5/8" diameter to accommodate locating fixtures and other "jigs" I have and am making. A frame jig for this bike will be constructed for the single purpose, but usable for something else if needed.

I've got to fab up a fixture for mounting my tubing notcher so I can use my Mag Drill to notch the ends. It will make a cleaner hole than using a hole cutter bit on the twist drill. So the swing arm planned for this bike will get machined and set up at my shared shop space, then I'll bring it home with the frame in front of me and notch it, weld it, and verify fitment.

I stay in a lot of Holiday Inns, and during their unlimited breakfast bar each morning, I read up on how to do stuff. Keeps me out of jail and away from stealing hub caps.

[SOHC4 Cafe Racer Fan]

did you learn all your skills Cal?
You are a veritable jackass

So the swing arm planned for this bike will get machined and set up at my shared shop space, then I'll bring it home with the frame in front of me and notch it, weld it, and verify fitment.

Is that until you finish the rebuild of the shop at home or is this a whole other can of whoop-ass?

[riverfever]

I vote that Cal opens Cal's Booty Camp for metal fabrication and electronics -- kind of like Colin Edwards' Texas Tornado Boot Camp, except for learning to fabricate frames and sheet metal, and to become a MotoGadget wiz.  What you pay to stay??

Fixed.

[riverfever]

I got the sturdy part covered...

That's gotta feel good looking at that thing. All done.

[bwaller]

Cal, I may not be following exactly, but you're planning to replace the backbone but not the headstock? It will be tricky to remove all the steel forming to get a solid base to weld to, but probably wise. You're replacing that main backbone with single large diameter tube or am I overtired?   

This is a 650 steering head removed just to see "what gives"

[calj737]

Brent - yes, remove all the gusset and expose the sole headstock. It will take some careful cutting to do so, but if I bought or machined a new headstock, then I'd lose the engraved VIN. I could duplicate the engraving (a buddy has a duplicator to engrave with) but I'd rather attempt to be mostly legal.

Once exposed, I'll turn it gently in the lathe to make sure I've got a solid core for welding. And yes, a single, 2" (probably) tube for the backbone. Gotta talk to the frame builder about his recommendations for tie ins and terminating the bone to the subframe. Lots to discuss and decide before I start altering the stock frame. I have another spare to work from as well in case things go sideways. Or I'll just use a replacement headstock.

[calj737]

Is that until you finish the rebuild of the shop at home or is this a whole other can of whoop-ass?

During the rebuild, I had to move what I could salvage somewhere. So I grabbed some space at my best bud's place. He's got 3-phase power there plus a lot more tooling than I do. He's a professional machinist and riflesmith, so anything I need, he has or knows. And when things really matter, he's always willing to jump in and do it for me. I help him with some other stuff as a trade-swap get even with each other. We laugh pretty hard about who owes who (we arm wrestle for the check at McDs).  He's a really good friend for a long, long time.

[bwaller]

I understand the concern about the VIN. Before you go too far could you stop by the police station and explain what you're planning. They might accept a new headstock if you transfer the VIN tag to the new piece if they witnessed old & new. At the shop we used to get the police to re-stamp any new headstocks, the only thing they insisted on. The original VIN tag rivots are spiral but quite short. They can be removed if you're careful then re-install with contact cement.

Be certain to adequately support whatever head you use....goes without saying I suppose!

[calj737]

No fear. My friend builds NASCAR frames for a living. He will make sure it's right, properly supported and spec'ed. He will even throw it on his testing jig afterwards to make sure it's right.

I have thought about the police route too. I'll do that if the original swap doesn't work out. I have connections with a few of their brass.

[SOHC4 Cafe Racer Fan]

I have thought about the police route too. I have connections with a few of their brass.

Nice to have friends in. The right places. Hmmm. If I have a custom frame project, I'm shipping to Cal!!

[calj737]

I am indeed fortunate. I have a wide network of folks that are, in my opinion, experts in their discipline. If I can't personally do it, I know someone who can at a very high level of professional skill. And usually they're reasonably priced or willing to swap favors. So that makes my projects very cost effective to undertake.

And some of them have extremely gracious to mentor me and/or allow me use of their facilities to do for myself. It's a good world out there and it's not hard to find the right answers from great people if you ask politely, and pay attention.

[SOHC4 Cafe Racer Fan]

I am indeed fortunate. I have a wide network of folks that are, in my opinion, experts in their discipline. If I can't personally do it, I know someone who can at a very high level of professional skill. And usually they're reasonably priced or willing to swap favors. So that makes my projects very cost effective to undertake.

And some of them have extremely gracious to mentor me and/or allow me use of their facilities to do for myself. It's a good world out there and it's not hard to find the right answers from great people if you ask politely, and pay attention.

Those are some great friends to have.  You've been extremely generous with your time and know-how here, as well. 

It's a little frustrating when you share some pearls of earned wisdom and people who asked for said advice shine you on.  Or those who benefit from your knowledge and forget to say, "Thank you" or at least pay it forward.

[calj737]

🙂 Fortunately, the world keeps spinning on its axis. Can't be dissuaded by others behavior from doing what's right.

I am lucky. Most of my research and decisions are long made before I post them here. I take guidance and advice from those who will deal with its consequences.