Garden Railway Forum

Trevor Thompson wrote: Sat Nov 09, 2024 9:51 am Philip

If you want the stl files for the Birmingham coaches - just ask. ......

What resin are you currently using?

Trevor

The F & B Birminghams are, I think, slightly different to the FR ones, not least because the wheels are up inside the body, under the seats, but I haven't looked in great detail. I'll keep it in mind though, thanks.

For some time I've been using the Sunlu ABS-like Water Washable in grey, but it seems to have become unobtainable recently. I used my last bit of it last night and I have a bottle of the Anycubic version being delivered today. Never used before so will have to see what happens. I did have some Elegoo water washable but that was rubbish and I wouldn't touch it again for all the resin in China!

Philip

Yes the coaches you are interested in are more akin to the Ashbury 4 wheel coaches on the Festiniog, but of course they are slightly different.

However the Ashbury drawings might be a good starting point - and I have drawn those. Sketchup drawings available if required.

The coal insert is now in place and I think it does what I was looking for:
Trevor

Your coal looks great now it's finished.

I have the F & B coach drawings in the book, so I'll be able to compare when I get that far.

Trevor Thompson wrote: Sun Nov 10, 2024 9:41 pm Philip

Yes the coaches you are interested in are more akin to the Ashbury 4 wheel coaches on the Festiniog, but of course they are slightly different.

Actually, I'm an idiot and got my Birmingham and Ashbury mixed up. The F & B ones ARE Ashbury, not Birmingham. Sorry.

It is a long time since I finished this model - but I still haven't been able to get it to run properly. It ran for a few laps at Peter's railway a couple of weeks ago pulling the new ballast wagons - but then it stopped - ceased solid.

The issues are to do with the resin printed chassis - and the way I assembled it.

Namely:

• Connecting rods bending
  connecting rods binding
  chassis warping

I have "gone off" resin printing somewhat!

So I have been applying my new found skills with fusion 360 to re-design the chassis, wheels, connecting rods, and motor mount. In particular I want to be able to replace the motor if required, and adjust its position accurately. Testing the assembly will be easier if I can separate the chassis form the footplate for testing. So to that end I am about to filament print these re-designed components:
I have made the motor mount in 2 parts screwed together, and the whole arrangement then screwed to the chassis via a slot each side so that it can be slid along to engage the gears properly.

I will let you know how I get on!

Trevor

I can't say that my modifications have resulted in success yet. When I put it all back together it didn't take long for one of the wheels to slip on the axle, causing the mechanism to stop.

I remember from my days modelling in 4mm scale using axles that have a squared end, and wondered if this might be a way forward.

So I have found appropriate axles made by Slaters Plasticard. They are intended for their 16mm scale locomotive kits. Expensive, but if this works it will be worth it, and become a standard way of working for me.

So the axles:
And the wheel I have drawn to fit it:
I have also altered the hole for the crank so that I can use heat fitted inserts.

The wheels printed out overnight so I'm off to see if they fit!

Trevor

Be interesting to see how you get on.
I had a similar slipping problem and solved it in a similar but different way. Not having lathe skills, I opted for D-shaped 3mm axles from AliExpress and then printed the wheels with a D-shaped axle hole. It just needs to print two versions with the D's at 90 deg. It works fine on my Quarry Hunslet and the F &B MW also has them although so far its only been test run. The slight downside is that the axle is not a full circle in the bearings, but that doesn't seem to matter so far, but the other positive is a flat face on the axle for the gear grub screw to lock against.

philipy wrote: Wed Jul 29, 2026 10:40 am Be interesting to see how you get on.
I had a similar slipping problem and solved it in a similar but different way. Not having lathe skills, I opted for D-shaped 3mm axles from AliExpress and then printed the wheels with a D-shaped axle hole. It just needs to print two versions with the D's at 90 deg. It works fine on my Quarry Hunslet and the F &B MW also has them although so far its only been test run. The slight downside is that the axle is not a full circle in the bearings, but that doesn't seem to matter so far, but the other positive is a flat face on the axle for the gear grub screw to lock against.

An interesting alternative - which I am sure will be much cheaper. I will keep that in mind. The CAD and printing makes little difference - square holes and countersink face - or a "D" all the way through.

Thanks for alerting me to the alternative solution.

The down side of the Slaters axle is the odd diameter of the axle - 4.7 mm diameter. That might be some obvious imperial measurement, but it does mean that I need a 4.8mm drill to make brass bearings

Trevor

Trevor Thompson wrote: Thu Jul 30, 2026 9:10 am The down side of the Slaters axle is the odd diameter of the axle - 4.7 mm diameter. That might be some obvious imperial measurement, but it does mean that I need a 4.8mm drill to make brass bearings

Slaters website states their loco axles are 3/16" dia. This seems to be the common O gauge size of driving axle and Walsall sell a similar design to the Slaters version.

There is also a note on Slaters website claiming there are undersize counterfeit axles in ciculation being sold on Ebay.......

3/16" is approx. 4.76 mm, but the nearest metric standard sizes of bright mild steel bar are 4 mm and 5 mm.

How did you measure the axles? I don't much trust digital calipers, as I checked the calibration of mine and it reads low across most of it's range. If I want accuracy, I use a micrometer.

Graeme