Lever Threads

[Orgasmatron]

I have an old (now polished and nickel plated) decompression lever, which I would like to use on my TT Rep to activate the cylinder barrel oiling system.
I am missing the screws, which appear to be 3/16″ and 32 tpi (although the one brass 3/16″ 32 tpi screw that I have seems to be a bit loose in the threaded holes and I wonder if 7/32″ might be correct).
Anyway, does this sound correct and, if so, where can I buy some (preferably nickel plated) domed cheese head screws?
Chris.

[Tman]

There were some odd-ball screws (“bastard sizes” as my old man used to term them..) around decades ago, but 7/32 sounds too obscure even for that.
I always thought levers and their clamps were usually a BA size? Maybe Google it and see…

[BRIAN MARSHALL]

Try and find a 1BA screw and see how that fits your lever. A throttle stop screw from an Amal pre-monobloc carburettor is 1BA if my memory isn’t playing tricks…
Brian

[Orgasmatron]

Thanks for the suggestion.
Yes, 7/16″ does seem strange. So, it’s probably 3/16″.
However, trying to find a dome headed, nickel plated (or otherwise) 3/16″ 32 tpi screw appears to be virtually impossible to find (even on the internet).
Hence my request for help to locate a manufacturer/seller.
Mr Marshall is the man who usually knows these things ; I wonder if he might even have a couple in his box(es) of spares.
Chris.

[Tman]

@BRIAN MARSHALL wrote:

Try and find a 1BA screw and see how that fits your lever. A throttle stop screw from an Amal pre-monobloc carburettor is 1BA if my memory isn’t playing tricks…
Brian

Unless it has the quick-thread slide lifter for a higher temporary tick-over..then it’s 3/16 Whit, if my memory isn’t playing tricks!

[efr215]

1BA

---

O.D. = 0.2087″ — 28.25tpi

3/16″ BSF — O.D. = 0.1875″ — 32tpi

3/16″ BSW — O.D. = 0.1875″ — 24tpi

7/32″ BSF — O.D. = 0.2188″ — 28tpi

While the 7/32″ BSF thread size is documented there is no BSW thread listed in that size.

A 5mm diameter thread is in the same ball park and has, within a “gnat’s nagger”, a 31.5tpi thread.

These are the likely candidates, there are others and it is not unknown for manufacturers to have their own threads just to make life difficult.

[Orgasmatron]

Thanks for the advise everyone.
Based on what you have told me, I found some 3/16″ BSF slightly domed cheese head screws on Ebay (polished silver too!).
Hopefully, they will fit.
Chris.

[Author]

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