Securing crankpin nuts

[David Thorpe]

For my latest loco I'm using Gibson wheels and crankpins. Although I've filed the crankpin bushes down to the width of the coupling rods, I've also had to file a fair bit off the crankpin nuts as well to ensure sufficient clearance between them and the footplate valance on the loco body. As a result the crankpin nuts are not as secure as they might be and like to fly off the wheel every few yards. So I was wondering about the best way of securing them. I've thought of a dab of solder, but am not at all sure that i'd manage to do that without the heat of the iron travelling down the crankpin and mucking up its already slightly doubtful relationship with the wheel. It would also mean that I'd never be able to get the things off again should the need arise. Preferable perhaps would be a touch of cyano on the end of the nut, but I'm worried that that might seize everything up and/or might not be sufficiently secure.

Any guidance on this would be most welcome.

DT

[Will L]

Loctite 243 will do the trick, but I also find if I hold them in a pin chuck and screw them up tight on the top hat crank pin bearing you shouldn't need the loctite.

Will

[Tim V]

Nuts shouldn't undo, perhaps you've shortened them too much?

[David Thorpe]

I probably have, but I had to in order to clear the valance.

DT

[nigelcliffe]

Poor man's loctite is varnish or shellac.
If borrowing a dab of nail varnish from the dressing table, avoid the bright colours and spangly types.

- Nigel

[David Thorpe]

Thanks everyone. In the knowledge that I have probably shortened the nuts too much, and in the absence of any shellac or nail varnish, I've ordered some Loctite 243. Any idea what its useful shelf life is likely to be once it's opened?

DT

[Paul Townsend]

Thanks everyone. In the knowledge that I have probably shortened the nuts too much, and in the absence of any shellac or nail varnish, I've ordered some Loctite 243. Any idea what its useful shelf life is likely to be once it's opened?

DT

Donkeys years, not like cyano $£%&* stuff which invariably goes off before I have used 1%

[Andy W]

"avoid the bright colours and spangly types" - damn, those are the only types I wear.

[Tim V]

If you have made them to short, then no amount of any glue/solder will keep the nuts on - as the rotation will surely undo the nuts You'll have to thin the coupling rods (slightly), then you won't need to glue them

[DougN]

One further solution to the problem but it is not a nice one is to use the crankpin nuts the other way round. IE the smaller diameter inside the rod. BUT the problem is to only open out the outer rod and not the inner rod.

The black Hawthorn on my Q6 thread has thrown a curve ball at me and I ended up using a crank pin washer on the back and the nut as the bearing on the front rods due to lack of space. Then it was still catching. SO the washer disappeared! Not the best practise but I seem to be winning the war with it at the moment. I am pretty sure I won't be bringing it to Scalefourum though to show!

I will see if I can get a photo or 2 for you. (Makes me think that the Macro lens for the camera isn't a bad idea but at 2loco kits in price...ummmmm

[martin goodall]

I confess to having dabbed the crankpins with solder in this situation. Apply phosphoric acid flux, and you shouldn't have to hang around long enough with the iron to melt the plastic in the wheel. But if the crank pins are brass screws (they usually are) they will conduct heat quickly, so you do need to be quick.

The other drawback is that once they are soldered, it is very difficult to get the crank pin nuts off again, so final fixing with solder should be left until you are absolutely sure that everything is finally adjusted and is working perfectly.