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Finally, I have my reversed speedo gearbox ready to fit. This might (possibly) be of interest to someone.
A few small details include an internal thrust washer of phosphor bronze. The new housing for the output shaft is also phosphor bronze, with an internal groove along its length to provide a path for grease lubricant. The original had a steel dish pressed into the body, with a split pin in case it tried to escape when it was greased.
Lots too many hours spent.
I don't suppose anyone can confirm the thread for the grub screw in the gear? I tried M3 and 6BA. It might be 7BA (which is very odd...). It's from NOC spares but has a threaded hole and no grub screw.
Nice conversion.
That's a nice mod that someone has made to overcome the problem. My pre war BSA has the drive on the right, the same casing as my 38 ES2 but the gears are skewed the opposite way to reverse rotation.
Which grub screw are you talking about? The ones that hold the bronze part into the Mazak housing?
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The 14 tooth gear is…
The 14 tooth gear is supposed to have a snug fit pin to secure it to the shaft. But the gear I bought only has a single tapped hole in the side of the boss. So far, I have drilled all the way through and fitted a split pin instead.
Ps it's my conversion. Took a lot longer than I expected....I might write it up if it's of interest.
ps...Smiths seem to have made both speedo and gearboxes in both hand directions. Very odd. Perhaps it was to simplify stock holding in the factory?
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I have fitted bushes.
I've fitted bushes to both of mine. The shafts don't wear but the casings are awful.
I don't know about the grub screws. 3/32 ME thread maybe or 2.5 mm. I've only seen gears with the through hole. 7 ba is very unusual (Lucas like the odd number BA sizes though).
Are you going for the pin drive or later speedo?
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I decided (was persuaded..)…
I decided (was persuaded..) to go for the later collar fixing to the speedo case. Allegedly it's more robust.
I've not (yet) indentifed a problem with my 16H. It's only got 6000 miles on what appears to be the original clock (it has the correct date on the plate underneath).
The casing holding the output shaft has a grease groove along the shaft. I think you would need to pump a lot of grease solidly into the gearbox to get grease to appear at the top of the shaft. And then I would worry about grease getting out from the input shaft and getting onto the brake linings!
I hope the phosphor bronze will last anyway. I'm not keen on the design. It can't be inspected without removing the wheel. And the gears must be meshed properly. The handbook suggests using heavy grease to check, but I used Blutack. I couldn't make sense of the marks in the grease.
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