Gear box end plate markings

[Knowledge]

I think I read somewhere that the number in a circle on the gear box end plate were of no significance.

Is that correct? I have a 2, 3 and a 5 in the drawer.

[Warkton Tornado No.1]

If you are talking of the 'original' components, I think they are the tooling designations for the die that is used in the forging process.

Innocenti would know which tooling required investigation if there were to be a problem with wear etc.

It would be the kind of scenario that SIL has learnt to happily ignore.....

[Knowledge]

Thanks. I suspected that this was a tooling number, butt hanks for the confirmation.

When a gear box end plate is advertised as "matched to the engine casing", what has actually been matched? Is it the centre-line of the layshaft, or the distance between the hub bearing and the inside of the end-plate?

[Warkton Tornado No.1]

I don’t know the answer to that but would hazard a guess...

The end-plates would have been produced to finite tolerances in days of old as the ferrous material utilised would have been more consistent than the casings they were fitted to.

Precisely how, then, Innocenti would have married any end-plate up to the casing is something we can only speculate.

It is fairly unlikely that the casing would have its Ø7 mm dowel holes reamed with the end plate in-situ which is what the likes of us engineering amateurs would do. I think you may agree.

So, my thinking is that the casings were also machined to finite tolerances (as the end-plates) ensuring interchange ability. The fact that the end-plate dowel holes are over-stamped to make them ‘blind’ would seem to back up this theory.

In my opinion, this concept is something that SIL were unable to conform to, so the production technique may have been changed to suit their ability.

In which case, I would imagine the casing would be assembled with its end-plate prior to final machining.

That final machining would probably be on a line borer which would produce the journals for the lay-shaft bearings & seals in one operation.

This is purely guesswork on my part, but the only explanation that I can come to terms with as ‘matched’ casings & end-plates is a recent phenomenon & very likely a retrograde measure compared to the finesse that Innocenti (& Eibar!) were able to demonstrate.

[rossclark]

^ that's pretty much how it's been explained previously. The endplate and casing are machined in the same operation.

It's generally held that the Indian casing and end plate should be kept together.

I've never had an alignment issue with Italian or Spanish mix and match parts.

[Knowledge]

Thanks. When the new shim arrives tomorrow, I might be back for more assistance.

Fingers crossed.