Help with Romford gears please

[hayfield]

I am sorting out my spares box and at the moment the gear box is in a mess

 

 

I am assuming the far right is 60-1 ratio, the small one on the left is 20-1

The second on the left came from a packet with 40-1 on it, but I have a feeling its a 30-1 and that the second on the left is the 40-1 as I dont think Romford did a 50-1

 

Please can someone more knowledgeable enlighten me

[hayfield]

The first gear has about 20 teeth and the second about 30, I am assuming the ratio means 20 teeth per rotation ? 

[Michael Edge]

From left, 20:1, 30:1, 40:1 and 60:1, as far as I know all Romford worms are single start.

[hayfield]

Michael

 

Thank you, I asked the question last night plus looked up on Google and looked at old W&H books

 

Firstly I now know much more about gears

Secondly I had a 30-1 gear set in a bag marked 40-1 (most of my Romford gears were either unmarked or loose

Some of my W&H books state Romford gears as 20-1, 30-1, 40-1 & 50-1  others 20-1, 30-1, 40-1 & 60-1, thanks for confirming the last one

 

I have quite a few gears with either no or broken grub screws, I think they are 10ba, is this correct and any idea where I can get a few please

[Michael Edge]

They are 10BA, to make one screw a 10BA steel screw into the boss and lock on to an axle. Saw this off close to the boss and saw a slot across. The problem with Romford grub screws is that they are far too long and break easily, ideally the slot in a grub screw should be just inside the thread.

[Pandora]

17 hours ago, hayfield said:

The first gear has about 20 teeth and the second about 30, I am assuming the ratio means 20 teeth per rotation ? 

It depends on the worm gear,  single start ofrdouble, look at the worm gear end on,  if you can see two threads starting  ( at 180 degrees ) it is a two start and the gear ration is half of the teeth on the main gearwheel

[Michael Edge]

I've never seen a two start Romford worm.

[hayfield]

Thanks again to everyone, its been a very useful learning curve and one I should have made years ago. I seem to have managed to find missing gears for an old DJH GB4.

 

I have two or 3 other gear boxes which I should also try and use (at least 2 styles of Alan Gibson ones

 

I am having a complete clear out of old fashioned gear sets and earlier open framed motors. I have decided to standardise on can motors and gearboxes from the likes of High Level, Comet and Branchlines. I seem to have no luck trying to mesh gea rsets using the older style motor mounts.

 

Motors are becoming interesting with the withdrawal of Mashima motors, Chris at High Level is now selling a coreless motor for under £30, I bought one at Scaleforum just not decided which loco to fit it in to. 

[Il Grifone]

IIRC the shaft centre spacing for Romford gears is 3/8". The usual advice is a sheet of thin paper between the gears to set the clearance. I have heard the 60:1 gears absorb a lot of the motor's power and are not recommended for this reason. (I only have experience of the 30:1 and  20:1 gears but have not had problems with either.

[Michael Edge]

High ratio worm gears are never very efficient, this is the main reason to change to the High Level type where the higher ratios are obtained by trains of spur gears. I still use Romford gears for some applications but only 20:1 and 30:1.