Mystery Screws

Some 35+ years ago now, I'm guessing 1974/5, I visited a motorcycle shop in Birmingham which specialised in British bikes. I went with a friend who had a 250 Triumph Trophy, whilst I still had a Honda CD175 at the time. We both progressed to Triumph 650 twins later.
Amongst my purchases was a bag of assorted "useful" screws and fixings. Lots of nuts, bolts, exhaust studs etc in a variety of imperial/British threads.

Ever since then I've been carrying round about 30 of these, in the hope that I'd find a use for them, but still haven't the foggiest what they are for.

Threaded 5/16" x 24, so presumably UNF.

Anyone any ideas of their original use, or even have a pressing need for a couple?

Bill

Bill,

they look as though they are designed to hold a ball away from a side outlet on a right angled check valve.

I have similar, but slightly different thoughts, though keeping them to my chest at the moment; I genuinely don't know what they came off.

Bill

Could they have been a form of locking screw which expanded the peg like extensions internally to hold critical components together?

They would have been sacrificial if repair was needed

Brian

How about if they were a form of pressure relief valve in the oil filter housing.

The 'ball' would be held against a seat with a spring set in the recess.

If the ball was lifted from its seat the excess oil would be discharged through the three gaps back to the sump.

Well, that was my original thought, but no idea off .what bike.

I think it might have been Vale Onslow we visited all those years ago.

Cheers Bill

Looks like the sort of thing you would find in the bowels of an old carburettor in the 70s

Patently obvious. It's a Spragforth 3 pin screw. Fitted to all pre 69 Howarth Spragforth Invaders. Holds a thingey in place behind the wotsit.

The lack of a decent flange for a fibre washer says to me that the pressure release idea might not be sound. And the idea of the self-locking pegs would surely destroy the threads in the housing when it was unscrewed?

I have only been messing with old motorbikes for 55 years, and I have never come across them. So, I guess they are fairly rare, which explain why Mr Onslow had lots, why they had gone rusty in stock, and why he was so keen to get rid of them in quantity.

Cheers, Tim

Nice rule.

When I first read this thread I did wonder if it was Vale Onslow, as a Brummie (long since exiled) I remember them well having been born in neighbouring Sparkhill.

Len continued to ride bikes until well past his 100th birthday, a remarkable man.

Bill D.

PS sorry Bill in response to your original question I am not a motorcycle expert although I have dabbled a bit back in the 60's, my younger brother was into racing. I have a vague recollection of taking something like this out of an old Royal Enfield and was part of the oil system as it pumped oil all over the place when we reassembled it, obviously badly.

Bill D.

Incidentally for anyone interested, my brother Mike Dawes (sadly late brother) was awarded the Pinhard prize in 1969 as a young secretary of the Midlands motor cycle racing club. The prize is awarded by the Sunbeam motorcycle club for services to the sport by people under 21. A visit to the club website will show all previous winners and Mike is amongst some big names, Surtees, Hailwood, Lamkin etc.

Bill D.

Bill...

I vaguely remember taking apart an engine many years ago and I am sure there was a magnetised ball bearing to pick up swarf fitted in the sump plug ..

Bob.

I think the rustyness is down to 40 years in my possession.

I seem to have that effect on things, often through lack of maintenance polishing.

Oddly even my high quality BT screwdrivers, pliers, spanners etc all turned rusty brown, then black, when I'd had them for a while. They were well looked after and well used, but my sweaty mitts always discolour tools, even when I keep them oiled.

Maybe a well known telescope builder on here could commission me instead of this local anodiser.

Bill

Edited By peak4 on 31/01/2018 02:27:28

Maybe a carby jet retaining plug for push in jets ? Or a bowl drain that uses the little prongs to line up the fuel pick up tube ? A ball detent cover screw ? Some form of one way valve or metering valve possibly in a fuel pump ? If you screw one into some flatbar so the prongs stick out tthe othere side it would make a nice back scratcher !