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Mystery Screws

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peak428/01/2018 14:17:49
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790 forum posts
67 photos

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?

Mystery Screw-1

Mystery Screw-2

Bill

Bob Rodgerson28/01/2018 14:59:53
571 forum posts
166 photos

Bill,

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

peak428/01/2018 15:13:08
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790 forum posts
67 photos
Posted by Bob Rodgerson on 28/01/2018 14:59:53:

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

Brian Wood29/01/2018 14:54:08
1931 forum posts
37 photos

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

J Hancock29/01/2018 17:53:02
297 forum posts

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.

peak429/01/2018 23:02:09
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790 forum posts
67 photos
Posted by J Hancock on 29/01/2018 17:53:02:

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

Ady130/01/2018 00:46:45
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3463 forum posts
513 photos

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

thaiguzzi30/01/2018 03:11:45
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544 forum posts
130 photos

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.

Phil Stevenson30/01/2018 10:33:53
73 forum posts
13 photos
Posted by peak4 on 29/01/2018 23:02:09:
Posted by J Hancock on 29/01/2018 17:53:02:

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

Sorry to digress, but what was left of Vale Onslow burnt down this week and is to be finally demolished.**LINK**

Tim Stevens30/01/2018 18:21:49
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1052 forum posts

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

Watford30/01/2018 18:41:37
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102 forum posts
8 photos

Nice rule. smiley

Bill Dawes30/01/2018 19:08:02
301 forum posts

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.

Bill Dawes30/01/2018 19:15:06
301 forum posts

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.

Bill Dawes30/01/2018 19:26:42
301 forum posts

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.

Bob Mc30/01/2018 19:36:23
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133 forum posts
26 photos

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.


peak431/01/2018 02:24:38
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790 forum posts
67 photos
Posted by Tim Stevens on 30/01/2018 18:21:49:

.......................................... 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

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

XD 35131/01/2018 04:42:00
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1297 forum posts
111 photos

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 !

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