Tuesday, February 06, 2024

Axle worms


Finally, some spare time to have another tinker with the O gauge Sentinel shunter. First time since November last year!

All the wheels and axles were looking a bit rusty. I think I'd missed some flux cleaning on the chassis, and fumes in the closed box has affected the surface. A hour with mild abrasive, a fibre pen and even Brasso saw them restored to good condition, at which point I noticed something odd. 

Each axle has a worm on the end, for the wheel to screw on to. The other is plain for an insulating plastic bush to slide on. 

I've never seen this before, and can't think of any good reason for it. Surely, some of the time, the wheel is rotating in a way that will unscrew it from the axle? I suppose a shunter is likely to travel as far backward as forward, but I just see the wheel coming off at some point, or at least unscrewing enough to make trackholding tricky. 

Can anyone explain? I'm confused.


Mark said...

Can't explain why, although I'm not sure it will be any worse than coupling rods that run on screws with a nut to hold them in place -- they easily undo themselves while testing quartering etc. before they are finally fixed on.

My guess would be a drop of loctite and you'll have no problem at all

Anonymous said...

It could be used to finely adjust the back to back. Then loctite it. It looks like there is room for a thin locknut. If that’s what it’s for that’s quite a clever idea.

Paul B. said...

There are two reasons that I can think of for threaded axles, firstly to make it easy to remove the wheelset for maintenance (noting that the chassis has inside bearings) and secondly to fine tune the back to back. Neither may apply!