Chassis Tolerance

[SteveW]

Following on from my half shaft thread (thanks for the reassurance that mine are as they should be), I am looking for views on how straight my chassis is before I bury it in the tub that I'm about to start work on. Bear with me, this isn't easy to explain!

According to 'TC Forever' the tolerance on the diagonals is 1/4". Mine was marginal on that so I did some straightening and they are now within 1/8", so all well and good.

However, when I sight along the chassis rails, one is visually dead straight and the other has a slight 'kink'. I have measured this accurately by marking both rails at 4" intervals and measuring the gap. The width of the chassis is 22 9/16" +/- 1/16" (TC Forever states 22 1/2", so this seems good to me) all the way from the rear to about 40" from the front. For the next 10" it gradually moves in to just over 22 3/8" and then for the next 10" back to 22 9/16" again. i.e., the maximum deflection from my average chassis width is just under 3/16" over a distance of 20". In metric money this is a maximum deflection of 4 mm.

I assume that these are reasonable tolerances to accept, but views would be appreciated.

[SteveW]

Pictures of rolling chassis (wheels not restored yet)

[SteveW]

OK, I decided that I couldn't live with the deflections in the chassis as rather confusingly described in my original posts. By using jacks and bits of wood, I've managed to halve the maximum deflection (now around 2mm in metric money). I've decided that I can easily live with this, especially since my diagonals as defined in TC Forever are well within tolerance and none of the deflection has any effect on the location of the front and rear axles.

[Steve Simmons]

I suppose you can't expect it to be perfect, considering how much they flex during use. Nice work.