Front beam and caster shims

Hi there
i am building a Chesil speedster, just got started.
i have been installing front beam on the main frame and been advised to use caster shims for greater stability. I am struggling to get the bottom beam to fit snugly into the frame there is a cm gap. Screwed up tight and it all appears secure btu I was just wondering if this will be ok/safe and if it negates the effect of the shim. culd it mean that beem is bent or frame not quite straight.

Thanks
Tim

Hmmmmm........

A cm is quite a bit. When I've assembled front beams to the frame head they usually fit snugly - maybe almost get piece of paper between them, but that's it.

Is it out at the top and bottom or just the bottom?? I would get in there with LOTS of light and see what's holding it away from the frame head. If nothing's interfering, then maybe borrow another beam and see if THAT makes a difference.

Remember that the receptacle for the beam on the frame head is just stamped sheet metal and it could be bent (or have rusted things in there), but, then, so could the beam.

When I've installed additional caster shims, the bottom tube fit snugly up against the frame head. I loosened all four bolts a bit and then pried the bottom tube out, maybe 1 CM or so, then slip the cast shim behind the tube - the shim is only 1/8" - 3/16" thick or so - not a whole lot.

gn

Thanks gordon
I'll get a closer look and be a little more accurate, I think 1cm was a bit of an exageration.
Tim

Tried again with shims same problem , not cm but still quite a gap. Here are soe photos with one of the 'good' side.
Tim

It looks like maybe you need to rotate the shims downward.

You can see that the shims are thicker in the middle and thinner on the edges. That is because both sides of the shims have the same radius as the frame head.

The shims should be rotated so that they are centered in the arc of the frame head.

The gap between shim and beam definitely looks too large. So is it the shim or the beam at fault here?

Have you tried to swap the shims left to right? Just to verify the two shims are identical. They should be.

Is it possible that there is a small bit of weld spatter or other interference on the beam itself? Inspect the surface with your fingers if possible. The shims should fit tightly to the beam, and even a small bit of unintended material between the shim and the beam can cause a large distortion. I had to file weld spatter off my revised beam.

That's all I can think of. Good luck.