Axel Box Clearances

I am currently in the fanal stages of refitting horn guide to an andrew barclay 0.4.0ST I am restoring.

The frames are now set up and horn guides are parallel etc, but I need to get the axel boxes machined and face plates manufactured.

The problem I have is that I am not too sure what clearances to give the boxes. I don't want to put too much side play in, and being a 4 wheeler it shouldn't need that much, but I don't want it going tight as the loco rocks on it's springs... does any one have a "rule of thumb" method for running tollerances?????

 

The LMA Handbook gives the machining tolerance of an axlebox of 0.000"+0.006" for the distance between the box flanges. The nominal design clearance should be 0.0625" upwards. With a four coupled where you don't need sideplay I would think that you should be looking at this minimum figure. Clearance between the hornguides should be between 0.002 and 0.010", depending on thesize of the box. As it's a four-coupled and probably a relatively small loco I'd go on the low side. The relevant pages are attached.

It is worth trying to get hold of a copy of this book, if you can.

HTH
Steve

 

Fantastic... Thanks, that's exactly the information I was looking for.

I'll keep a look out for a copy of that!!!

Cheers.