The LNER Encyclopedia

I have recently picked up a kit-built J39 (supposedly in running order).
It is powered by an Escap RG4 but the bevel gear that attaches the motor shaft to the gearbox is missing.

Does anyone know where I can pick up a replacement or even has a picture of one so I know exactly what I am looking for?

Closeup of RG4 gearbox, showing bevel gear: Hope this helps.

G'day all

I thought that a problem with Portescap motors was that the gears wore and the gearbox became noisy until it wore out.

When the supply of gearboxes ceased, the marketing of Portescap RG4s stopped.

Earlswood nob

The issue with Portescap gearboxes as far as I know is that the later gearboxes were the noisy ones - it generally had nothing to do with wearing out.

I have a lot of Portescaps that are in locos, a number of which have run many real miles I'm sure over the last 25-35 years, and none have worn out. Examples of such locos are O2, O4, B2, B3, B5 (admittedly this one is a trifle noisy but possibly the driving axle bearings might need to be renewed?), B16/1, C2, J15, J6, W1, P2. Most of which have run continuously many times for hours and hours on my layout.

I did once have an issue with a tooth being damaged on the bevel gear in a Q6 which I remedied by prising the gear a bit further away from the motor so the mesh was a bit closer.

The best source of a bevel gear might be from someone who has a Portescap that has either worn out (provided the bevel gear is ok) or been damaged. I actually have a spare gearbox but will use it on a secondhand Portescap I picked up for a song that has a tight gearbox - I have no idea how it has been treated but I think the motor is ok.

Woodcock29

Afternoon all

Thanks Woodcock for the info.

My Portescaps never get much use and those that I have left, are still in good condition. This means that I've never worn one out, but was relying on heresay.

Earlswood nob

I use nothing but Portescaps or Maxons.

The bevel gear is impossible to replace unless you have a spare but knackered RG4. Bevel drives are very efficient and it's a real shame that the various gearbox specialists don't offer this option instead of endless bloody worms.

It's not a job that I would take on but I wonder if replica gears could be cast in a suitable resin, given a master, and whether they would stand up reasonably to time and use.

Thank you all for your replies (especially for the photo).
So it looks like unless I can find another old unit for spares, I will have to look for another way to power the loco.

I wonder if a 3D printer could be used to make the missing gear.

When I was shown the prototype gearbox in Eastbourne about 1978/81ish I'm sure that Ken Pelling had used Brass Gears. It may be productive to contact Kean Maygib as I know they still exist.

Just checked the CLAG website Kean Maygib 01603 720 792. It may be best to try to speak with Ken although he was poorly some time ago and you may need to make an appointment.

If you take your gear box to a company that produces small gears, they maybe able cut you a new bevel. But it is not going to be cheap. I suggest starting with someone like HPC gears, they probably won't be able to help, but may be able to suggest someone who can.

Thanks Bill for the suggestion.
They are a long way from Australia, but as it happens I plan to be in the UK later this year.

I wonder if any of their off the shelf gears would work.

Muzza wrote:.....I wonder if any of their off the shelf gears would work.

No, because none of HPC's ready-made range are small enough.

My understanding was that the bevel gears were produced by Davall.

Muzza wrote:Thanks Bill for the suggestion.
They are a long way from Australia, but as it happens I plan to be in the UK later this year.

You could google for Australian gear makers....

billbedford wrote:

Muzza wrote:Thanks Bill for the suggestion.
They are a long way from Australia, but as it happens I plan to be in the UK later this year.

You could google for Australian gear makers....

Indeed - and I will.

Thanks.