Drive tube?

[Still trying]

Hi just have a question about a drive tube I have. It is 20 inches long and appears to have the clutch thread on the mounting bracket but it only has an inner diameter of 1/2 an inch which is quite small so the driveshaft must be really small, what motor would that have come off? Drive shaft must have been a needle.
Cheers Bob

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[tambikerboy]

Hi bob only ever seen one like that before it had a brass bush inserted into the top of it could this be the same as yours if so just remove the bush. ... (just thinking out loud) i would of thought all drive shafts where the same dimensions

[Still trying]

Hi the previous images didn't work (hate technology) anyway I had a look and yeah it has a brass bush but it's on the bottom of the tube. it's all weird to me as I'm just learning about seagulls. Would this bush some how support a pinion or something like that?

[Still trying]

Would the shaft have anything to do with this tapered shaft and the other thing?

[Still trying]

I meant would the tube have anything in common with the tapered shaft and the other bit?
Cheers Bob

[tambikerboy]

It might be that the bush should be on the gearbox and not in the drive tube as i said i only ever seen one like it before but I'm sure you will get all your answers here. ...

[Oyster 49]

The brass/bronze bush at the bottom of the drive tube is correct for a SD engine. The water pump housing also has a oil/grease nipple to allow the bush to be lubricated, hence the hole in the bush. It's there to support the top of the pinion shaft, but was deleted early post war onwards.

Not sure if that bush is also present in pre war engines such as the Marston ON/OP series. I'm sure Charles will be able to confirm.

Anyway definitely a SD feature, I'm not sure when exactly it was deleted, sometime before 1950 I suspect.

[headdownarseup]

Same in the very early post war 102's up to around 1949 with a "straight out the back" exhaust outlet.

It's a support bearing for the pinion as Oyster has mentioned.
Drive shafts (the square tube) can vary a little bit in dimensions (wall thickness) as do the lengths (standard or long shaft)
Torque tubes (often plated or chromed) can vary as well. Earlier ones not so much, but later type tubes are sometimes quite specific in what they fit.

Clutch pivot pins (i think) are all the same for post war motors until the first of the modern FNR type motors appear in the late 1970's.


Jon

[Still trying]

Thanks for the info. Handy to know if I happen to stumble upon an sd sometime and buy it that I have a spare bit for it.
Cheers