Anyone have a source for the diagonal frame measurements as might be used for aftermarket rails when using original crossmembers?
Diagonal measurments should match side to side as long as you use exact matching measuring points. You are seeking to have it square. Folks may not have the exact measurements on their X simply because of where they pick to measure from and to.
I've built a few deuce frames with ASC rails and I start by bolting in stock width front and rear spreader bars. I set the proper width in the center of the frame with square tube bars with the right width holes that I install on the front firewall holes, midway at the holes about in the center and in the holes just as the frame begins to go uphill at the back. I take my tape and measure diagonally between the main firewall hole and the last hole before the kick up to establish square. I paid more attention to the outside width of the frame than the body hole dimensions. I always figured if the frame was the right width the holes would be right. I'm usually working with boxed rails so when I get the frame squared and make sure the sides are vertical I tack the rails to my table. I have had the Wescott blueprints on my walls since they became available. Then I install my X member which I make. Mine does not hang below the rails so I could install it with the frame flat on the table. Not as sophisticated as some but has worked for me for 40+ years. Did 100's of deuce frames this way.
Here are some examples that might give you some ideas........... Personally I'm planning to build similar to the TCI chassis with the box tubing x member as I feel it should be very strong and gives room for routing exhausts. Some guys like the more complicated look shown in some other examples.
Thanks, I'm doing something probably against all odds, & have done frames in part similar to the method krylon32 describes, but not having a work platform, or an accessible frame I'm using my mower trailer to mount a pair of UPI subrails to the existing 12" high heavy iron trailer side rails in accordance with the same blueprint dimensions as shown by Mr48chev, this I know sounds counterintuitive, but will initially be used to support a body without a floor while sandblasting, etc. at a decent work height. the forward & rear most mounting holes are cross braced & are diagonally equal, the center cross brace areas will be properly supported & measure correctly to the blueprint. I would suspect a rash of Why? comments & the surface of a trailer being far from ideal, it will provide some mobility & be carefully checked along the way should I progress to consider welding & panel work..
I’ve been through a similar situation when I was upgrading my frame and trying to fit aftermarket rails. It can be tricky figuring out those diagonal frame measurements. What really helped me was using a tool from https://ruler.onl/—it gave me a clear visual and precise measurements that made the process a lot smoother. I’d recommend checking out tools like that to ensure everything lines up perfectly with your original crossmembers. It made a huge difference for me, and I’m sure it’ll help you get those measurements just right!
Use the x² = y² ÷ z² using the chosen place you wanted to measure from to get the diagonal measurement.
I'd suggest getting some "Tram" pointers and making a Tram. Then you can verify that all the holes are the same distance apart accurately. By that I mean both the side to side locations and then the diagonals. The points drop into the holes so you can tell exactly rather than pretty close with a tape measure . Amazon has these for about $30......then you need some bar stock to fit them on.
Thanks for all the replies, hope to have a pair of rails by the end of the year and will be back to reread everything. Bob
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