Making round tube oval-ishDIY Si - 23/8/12 at 09:51 AM
Morning all.
I've been having a look at the beginnings of my exhausts, and have a slight problem. The original cad file for the flanges was designed for 1
5/8" tube, but that's a bit big for my engine, so I got a mate to re-draw the ports a little smaller, with an ID that we thought would match
the OD of the 1.5" tube I'm using. However, my first attempt at flattening the round tube out to match has produced this result, and I
suspect the ports could have done with being a fraction smaller:
Due to having to flatten it in my vice, the end of the tube is tapered, which doesn't help. But I can't think of another simple way of doing
this.
So how can I best go about making the two shapes match? I can't afford to get the flanges re-done as number 1 son has just arrived, and
money's a bit tight. The first thought I had, given that I'll be MIG welding the lot together is to put a thickish bead down and then grind
the bit of the tube within the flange back to shape. Not the best idea I know, but it'll probably only cost me time. I'd rather there be a
sensible way of making the shapes match though!
Minicooper - 23/8/12 at 09:58 AM
I would weld were they touch then use the heat to form and panel beat the lip tighter around the edge, once you have some heat in it, it's very
easy to form the metal
Cheers
David
liam.mccaffrey - 23/8/12 at 10:08 AM
I saw an amazing video of exactly this technique a few years ago i saved it on my generic satellite recording device, but it went south and we lost
it.
The program was wreck rescue presented by Mark "Is Born" Evans and it was the edition where they restored an old single seater Elver?? race
car.
Basically they put the flange in the vice and with the pipe tacked in one place they put a piece of 3/4" solid bar inside the pipe and gently
hammered the bar against the inside of the pipe to form it to the flange profile and tacked as they went. Voila perfect fit.
When you see something like this, its like magic how well it works.
Many thanks, I hadn't though of doing it that way. Looks much easier than I expected too, as even I can heat a tube and hit it with a hammer, so
I've got a fair chance of getting it right!!
liam.mccaffrey - 23/8/12 at 10:57 AM
im not sure you'd even need to heat it?! Best of luck let us know how you get on
Fred W B - 23/8/12 at 11:18 AM
If you can find a piece of solid material a bit bigger then the port size, dress it to the shape of the port with an angle grinder and flex back. Put
a bit of a taper on it. Hammer or press the resultant shape into the pipes, or use it as a dolly.
cheers
Fred W B
DIY Si - 23/8/12 at 11:20 AM
quote:Originally posted by Fred W B
If you can find a piece of solid material a bit bigger then the port size, dress it to the shape of the port with an angle grinder and flex back. Put
a bit of a taper on it. Hammer or press the resultant shape into the pipes, or use it as a dolly.
cheers
Fred W B
That was my other thought, but the only things I have that might do are bits of soft wood, and I don't think they'd be up to the task.
I'll give the first method a try and see how I get on.
FuryRebuild - 23/8/12 at 11:45 AM
