Coupling rod knuckle question

[Andy W]

I'm building a pair of coupling rods pivoted on the knuckles as described in Will's excellent topic: viewtopic.php?p=6738#p6738

I'm just about to fit them, but I've noticed that the distance between the knuckles and axle holes aren't the same on the jointed rod - they're out by a very small amount (0.2mm?). Both rods' axle holes line up perfectly, it's just the knuckle to final hole that differs.

Is this likely to be a problem?

[grovenor-2685]

No.
Keith

[Will L]

I agree with Keith.

In the grand scheme of things, 0.2mm isn't much of an error, depending on how you did it could be as much in the measurement as the item, although rods is a good place to minimise on such things. I'd be interested to know where it came from.

[Tim V]

Are you saying that the combined length of one rod is different to the combined length of the other?

[Andy W]

No the rods are the same, they fit the jigs. I must have drilled the knuckle hole in one pair slightly forwards or aft. The articulation works on both pairs - but the joints themselves don't match. More difficult to explain than make! Thanks for the thoughts.

[Andy W]

Well Keith etc were right. The chassis works just fine:





In fact it runs very smoothly. I normally don't add a flywheel, but as this is a big (for the MR) tank - it's a U/S class - and I had one spare I used it.

Thanks for all the advice - I couldn't get my head around the physics of the problem.