Hi Roy

You may be better off posting this question on the Model Engineer Proboards forum, it is much more locomotive based than this one, many active loco builders on their with a wealth of experience.

I can’t really help much with your question as I’ve never used needle rollers on axleboxes, the big problem I believe would be keeping ash and grit out. The only time I have seen them used the builders have used cannon axleboxes for that reason. I have two high mileage locomotives ( with plain bearings) and on both the trailing axleboxes have worn excessively due to being directly below the ashpan, and the ash and oil had formed a very effective grinding paste. On one of them I’ve just converted the rear axle to cannon boxes.

On John Baguley’s excellent website there is his build log of Helen Longish which has a description of some experiments he carried out on the needle roller axles for his locomotive. Hoping the above may be of some use.

Dave

Greetings Roy, the Torquay Manor design makes a fine model which you will be pleased with.  I would not use needle rollers, which need to run on a hardened axle, having found they break up due to grit & dirt getting in, which mixed with stray lubricating oil which always seems to be about under a loco, make excellent grinding paste.  I would, and do, use plain cast iron axleboxes, or split if you really want to use them, but with a cannon axlebox to try to keep out the muck.

Good luck with your Manor

Regards

Brian B

Hello Roy. I used needle roller bearings on my 71/4″ 9F. I was fortunate in obtaining needle roller bearings with inner hardened races. I personally would not use needle roller bearings unless they run on hardened inner races. To use roller bearings, i did have to re-design the horn block guides, opening them slightly to provide more material on the inner sides of the axle box, which is the issue you have. I also fitted made cannon box sleeves so the axles runs in a sealed tube filled with grease and fitted oil seals on the outer sides of the axle boxes to ensure dirt does not enter. So to use needle roller or other similar rolling bearings you do need to give a lot of thought to the issues early on. I hope this helps. Good luck. Howard

I have used working leaf springs on 2 locos. The first one used springs made from steel strapping bands, and works well. It has the same number of leaves as the original loco but because the steel strip is very thin the depth of the spring pack is nowhere near scale but the spring rate seems about right. For the second one I am using band-saw blade with the teeth removed. These are much thicker than the steel strapping and the springs for this loco are very stiff if made up using the required number of leaves to match the depth of the spring pack on the original loco. It is a 2-4-2 tank loco for 5inch gauge and I can stand fully on the chassis without the axle boxes moving more than about half the available travel. I can’t imagine the completed loco weighing 85kg so the springs are obviously too stiff. I will be experimenting with this loco by replacing progressive number of steel leaves with plastic ones until the spring rate is suitable.

I agree with Duncan and have not found leaf springs at all ‘bouncy’ as the friction between the leaves provides a measure of damping that is not available from a coil spring.

I’ve just acquired a part built chassis for  5″g Tom Rolt. the springs have 5 leaves 16g. They do not move. This will be an early mod when I’ve got some of the other jobs whittled down.

If you read the bumph for Tufnol it says the resin used is thermosetting, so it shouldn’t be possible to heat set it, but I know people do it, so I’m confused. An alternative would be plasticard, which is thermoplastic, and available in black. In reality it’s only there to take up space and look right, so it’s mechanical properties don’t matter as long as you allow for it in the steel ones.