Locomotive axle length- clearance between wheels and axle boxes

[Peter DawesParticipant @peterdawes59802]

Hi there,

I’m currently building a simplex 0-6-0 loco and i have built a rolling chassis, wheels in place etc etc, to come to find that there is significant sideways play between the wheels and axle boxes (the chassis can be pushed side to side with the wheels held still). Upon checking the dimensions on the drawings reveals that there should be a 1/32″ gap either side (the axle length-between the shoulders- is 1/16″ longer than the gap between the outer faces of the axles blocks). Is this an error or a deliberate thing? Something to aid cornering perhaps…. I would have thought this could compromise the connecting rods etc?

I appreciate the help

P

[Peter DawesParticipant @peterdawes59802]

[Clive HartlandParticipant @clivehartland94829]

This is interesting as I am making a 2-10-0 Evening Star in three and a half inch gauge and I also wondered about axle end float.

With 10 driving wheels the Evening Star has a problem getting around curves and the driving links have a lot of end float as well.

I did find some very close tolerance at the front end of the chassi but managed to clear that.

You cannot scale down and achieve all the same clearances as a full size loco.

Your clearances sound about right though Peter.

 

Clive

[DustyParticipant @dusty]

You should build in some slop in the motion,ie; the coupling rods, and make sure the axle boxes are not too snug in the horns in the transverse direction. The loco has to negotiate some very out of scale track alignment. If everything is nice and snug it will bind as you travel along the track and you will wonder why your masterpiece is not performing as it should. Remember the sound of the old steam locos clanking and clonking? well I can, even if some of you yougsters can’t. On the question of end float, it allows the wheels on one side of the loco to rise without fouling the axlebox.

[DMBParticipant @dmb]

I remember the West Countrys on down trains from Brighton, stopping at “Portslade & West Hove” station when Iwas a kid. Did they clonk, some of them.

[Clive HartlandParticipant @clivehartland94829]

I also ‘Rounded’ the axle brg. guides so that the axles could rise and fall without binding.

That is one wheel of the axle could lift and not stick in the guides, hard to describe but essential. Particularly on the Evening Star with all those wheels.

 

Clive

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