Model Railway Forum

I have a problem with a crank pin that keeps coming out. If I tighten it right up the connecting rods won’t move and if I don’t it comes undone when running.

Logic suggests that I need to put a spot of some thread lock (one that allows you to unscrew it again if you have to) on the tip of the screw but before I do I thought that it would be best to ask here first, is that the best way to overcome my problem and can anyone suggest a suitable product?

Thank you

What make is it?

Was it new when you bought it?

If you do want to 'lock' it in place try a very small drop of varnish or paint which will give way if you do need to undo it later.

It shouldn’t be possible to tighten the screw so much that it locks the connecting rods. It is either the wrong screw or a spacer is missing.

The maker of the loco would help.

The loco is a Bachmann 32-561 Class A1 60122 Curlew BR Express Blue Early Emblem bought new with DCC sound from Hattons in Jan 2018.

I thought about the possibility of a missing spacer, but the other side appears to be put together in the same way, without a spacer. Looking at the document that came with the loco I cannot tell what should be there.

The crank pin is the original one, it is the one on the middle drive wheel, the head fits into a recess on a rod whilst the thread screws into the top of a round pillar that has other rods fitting over it.

I have had another loose bolt problem on this loco, the head coming out far enough to cause a connecting rod to jam up, but that has tightened up OK and appears to be staying in place.

Contacting Bachmann sounds like a good idea.

Use lacquer, hmm my wife has a couple of bottles of that but what colour?

Flamingo starburst?

That is very hard to get since you purchased most of it for yourself Steve. I have to use something different now.

Sunny pink is more my colour

I think that the sunny pink was just right, the crank pin came out again after the first attempt so I put it back in with more of the thread coated and test run it again. It appears to be holding.