Hi John, Great intention to make parts available again!
But remember there is already a very clever alternative for the clutch spring available from THB Support which tackles the occasional tilting problem with the original spring: Multiple small springs placed in a circle which guarantee a straight lift.
I have to admit I have never tried one myself but heard good reviews about it....
The Cush Drive springs 15-46 made its first appearance in 1923 on 2 3/4HP flat tankers.
And is used on all models except 250 and some V twin.
They used a shouldered nut that only work with square material not round, and a lock nut.
Also they at first use a six lobe sprocket.
These can be replaced with a four lobe with has the same bore.
Hi all
The spring manufacturer has sourced “square” section wire but is obliged to buy 200kg at a time which means from a commercial venture, it makes no sense for him
It leaves us riders potentially with a problem for future in the availability of such important components - no springs - no go
However - he has sourced a limited quantity of round wire which can be adapted / modified & finished to that of the “square” section we are used to & fit into the clutch tool mentioned on other threads on this forum - your tool Michiel
Dimensionally the same - but still round section
Of course price is dictated by volume ordered but if ordered in quantity - I expect pricing to be a maximum of £15 per spring
I would be doing this as a one off order
If you are interested- please contact me with your interest & quantity required - this isn’t a commitment to buy but to guage interest & obtain more clarity on final pricing
To clarify this is for
Clutch Spring
Cush drive spring
Darren
He has an nos Cush drive spring from me - if this spring needs to be further modified it can be done to match existing securing methods
These springs will fit other bsa models - more knowledgeable people than me will know
Br
Jo’b
Hi all
Based on the low level of interest in getting springs made, I will not be proceeding with getting these done
Thanks to those who did contact me on this
Br
Jo’b
Some one must be making square section springs because I bought 4 of them last year fromBill Green when he was selling down his stock prior to the proposed sale of the business which fell through.
I would guess they originated in India where he got a lot of parts made but these seemed to be good as I am using one right now & have another in the model S .
The M20 one has done quite a few thousand miles on his spring without any problems .
Hi Trevor could they be new old stock as Bill sold me complete float bodies a while ago that were left behind in India by the British. He had some good bits prior to getting parts made in India. He offered me carburetter parts last year but as soon as I saw the finish on them I knew they were Indian made and inferior quality.
Whilst sourcing other springs I thought I would look at the clutch spring and the crank shock absorber too as John has given up. At a push they could use the same wire.
To start with they are not made from rectangular wire, so new tooling will have to be made for the wire. If it was rectangular, the metre long piece of wire would be about £30.00ukp for carbon steel wire. I didn't ask about silicon chrome steel wire, but that would give a better life.
So once you have the wire in the correct profile, it seems the spring winder also needs bespoke tooling.
I haven't given up the research, but it's that same old thing again. How much would someone pay for a spring?
50 metres of rectangular wire is about £1500.00ukp, so not unreasonable.
Test figures (specs.)for the springs are available and round wire would do the job as long as the poundage was correct...I guess it's down to asking a spring maker whether the poundage and essential dimensions provided are possible with a round wire...
Later BSAs did use round wire for the engine shock absorber when the change was made from 4 lobe to 2 lobe cams but the poundage was completely different as the gentler radii of the 2 lobe type cam required a heavier spring for correct operation...Ian