tach drive housing types

[Ventodue]

Thanks to everyone for their contributions to this rather esoteric subject .

Here's the 'photomontage' revised - we're up to 11, possibly 12, models now ! Apologies if I missed or confused something - as always, corrections/revisions/additions welcome!

[450jupiter]

In Massimo Clarke's book, a racing 350 used by Bruno Spaggiari in 1968 was configured to drain the oil to the cam drive tower.

[DBDBrian]

Hi Rick
Thanks for posting the parts sheet, I have taken the liberty of printing it off, I trust that’s ok. Interestingly it lists the drive as Smiths, I think we can take that as proof positive as to the manufacturer.
The gears in my drive are as I acquired it. It didn’t come with my machine. The gear and shaft are integral, I machined it off and fitted it onto the new shaft.
The rotation with the unit assembled output under input is, input shaft viewed from drive end, (In Anti-Clock), output viewed from cable end, (Out Clock), ratio is 2 IN 1 out. This would be the set for an Anti-Clock (IN)
4-1 instrument.
This works out ok for the Smiths Chronometric I intend to use, But I don’t know what the input rotation is for a Veglia? Smiths also made Clock (IN) instruments.
It seems strange there are two sets of gears, as the rotation can be changed according to assembly. It does alter the axial thrust, but input rotation would have the same effect. I did wonder if it was to keep the thrust off the end caps to prevent them unscrewing. but I think one cap would be in contact regardless, and not always in sympathy with the thread, and it would need to be stamped for it's intended rotation.
There is certainly more too this subject than meets the eye.

Brian

Attached
Gears for my drive.
The Smiths Chronometric I have adapted to simulate the Veglia mounting, it has yet to be stripped and painted.

P1040568.JPG

P1040558.JPG

P1040564.JPG

P1040562.JPG

cao

[nalimugmug]

Hi,

For what its worth-here is the drive on my 1996 Mach 1.

DSC_4644.JPG

[double diamond]

These reverse rotation drives may also have been included in the kits that positioned the drive unit on the clutch cover, driven by the end of the crankshaft.

[Rick]

Brian-
It sounds like your Smiths drive has the right gears for a 'output under input' configuration- this picture is of the other, non Smiths, gearbox:

rotation.jpg

And, a photo of a broken input shaft- no idea where I got it, but the gear is keyed onto the shaft- not sure what kept it from from moving axially- must have been a thrust washer:

worm shaft.jpg

How did you secure your gear to the shaft? The other loose shaft I have looks like the gear and shaft are separate pieces, but no idea how they fixed it to the shaft- no key.
I have the 1962 SCR parts book as a pdf- send me a PM with your email address if you'd like it.
Your bracket looks good- seeing the gearbox mounted to the tachometer makes my head swim- does it reverse the rotation again?
Matt-
or anyone- have you ever seen a tach driven from the crankshaft?
I found a photo that shows a Smiths drive reversed- the way I'll need to configure the ones I have.

1955 ducati 125.jpg

Rick

[DBDBrian]

Yes Rick,I would very much like to have the file, thanks, I will PM you my address.
The angle drive on the tacho does indeed reverse the drive yet again.

The gear was shrunk onto the shaft.The new shaft was oversize on the o/d as I had to ream the housing due to wear. When I machined the gear off the old shaft, I bored it a few thou under the original shaft size. The new shaft was then machined on the end to plus .0006” thou up on the gear bore, (if memory serves correct) which left a small shoulder on the shaft, the gear was heated and dropped on to locate against the shoulder.
Brian

The primary case drive which Matt mentions, was an after market fitment, from Vic Camp in the UK, using Smiths equipment.
Picture from Mick Walker's Ducati Singles.

SCAN0007.JPG

[Ventodue]

For what its worth - here is the drive on my 1996 Mach 1.

Thanks. Well, to my tired eyes, that looks like yet another variation 'cos the drive box is flat on the front, not rounded ...






P.s I guess you meant 1966, not 1996 ...?

[nalimugmug]

No excuses-was just back from the pub when I posted-yes 1966

[DBDBrian]

Not the tach drive housing, but related in as much as the drive slot in the camshaft, I have a shaft without the slot, I think it is genuine Ducati, Were the early models some and some? Or did the slot arrive at a given date. Maybe a reason for the after market drive off the primary side.
Brian.

P1040587.JPG