I've got to make a decission on the mounting of my 31 roadster body on my duece frame. I'd like to use the holes that came in the rails but I plan to box the frame and I'm worried about whatever threaded device I have in the rails and my innability to get to it once the rail is boxed... I've seen people create mounting tabs for the body but I really would like to avoid adding any 'clutter' to the frame... So what to use and why? Mounting tabs Nut welded to the inside of the frame rail Cage Nuts Some other welded insert... Ideas?...
Weld in a threaded bung. Its a clean way, then safety wire the bolts. I guess the cons would be not much room for misalignment.
you can weld a nut on the inside of the top rail before you put the boxing plate on .... Gary's threaded bung will work or use an expandable nut-sert ... I like the welded ideas better as I have had nut-sert spin on me ... Shouldn't be a problem as you will never have to remove the body once assembled.
On mine, I welded a washer and a bolt to the underside of top rail of the frame. I used a bolt, and a nut on the top side of the frame to hold everything in place while I welded, which also had the bonus effect of keeping the threads from getting warped noticeably. I plan on using a reasonably long bolt (that goes down below the bottom of the nut) and some loctite when the body gets bolted down.
Square nuts welded to the top/inside of frame rail. Use at least a bolt that's 1.5 inches long, use a nut on top of the outside of the rail, snugged up to hold the square nut straight and flush. I like to just tack them, then take the bolt out and hard weld it. Don't forget to chase it with a tap. Square nuts are thicker as well as wider across the flats, so if it gets cross threaded or fouled, there is enough material to drill/tap to the next larger size.
I really like the way that looks Neal and that RPU build is one of my favorites ever on the HAMB... And I thought about access hole/lightening holes... But my concern is that I wonder how much coating coverage inside the rails you'll actually get when it comes time to prime/paint it, and how well it'll stand up to water and grime getting in there. Belled lightening/access holes were always my first choice... But I'm just a little hung-up on that issue. Cage nuts were my second choice, but it'd be a bitch if the cage let go inside the rail... I think the next best option is the threaded insert... Which I guess I could use to replace a broken cage if that ever happened. Any other thoughts?
Box you frame in with dimpled holes like the Ionia Guys do so that access is available through out the frame. If your already past this stage then cutting a access hole may be the better option.
Kilroy - This might be a completely ridiculous and over-thought solution, but you might find it helpful. I've owned a few high end steel bicycle frames and was always paranoid about rust. I used "JP Weigle's frame saver" inside all of the tubes. I ended up making this contraption with part of a spray nozzle and some really small aquarium tubing. Basically threaded it down the frame tubes from the bottom bracket, started spraying and slowly pulled it out as the inside was coated. I think a similar setup threaded down the inside of a frame rail would work.
I will either weld a bung into the frame or rivet nuts are cool if you are not good with a tig or do not have a tig unit. I got my kit at the local paint supply store, you should check into these. Very neat and easy..
I think that's a good idea Kevin and should work... I guess also that if you punch enough holes in the boxing plates, you can do a pretty good job of covering the inside of the rails too. Maybe even with an appropriate sized brush... When I raced, I had my eye on a Chromolly Colnago... But I was never successfull enough to justify the expense... Can't imagine what I would have done if I actually got it and the tubes rusted through...
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