[Brian Petheram]

This interesting - it seems the design evolved over the years. I did a lot of searching both of this forum and on the wider web but most of the mentions of clutch stops relate to adjustment rather than construction or repair. I have already remade my stops and will go for a test run when it stops raining - all seems well on the bench. The way they work seems quite straightforward and the stresses should be fairly slight if the clutch is not dragging.
I am no engineer but the very shallow cups on my holders seemed wrong to me but they were both the same and I assume they are original - I can't imagine that the holders would ever wear out! 10mm with a 3/16 protrusion seems a much better design for the purpose. Having said that, I am working with what I have and ended up with about a 8mm protrusion. I settled on this partly because that length gives a decent range of adjustment leeway taking into acount the distance between the cover and the clutch and the overall length of the clutch stop holders.
Regarding the material, the fractionally smaller diameter relative to my parts mean that they are sitting in essentially a cup of araldite which is probably preferable than a tight fit on such a shallow holding piece. If the holders were about 10mm deep then a tight fit would be better with a dab of araldite in the bottom of the holder. A post on a previous thread in this forum said they were originally leather. The remaining one I dug out was cork, but I doubt the material is critical if it has sufficient shear strength and a reasonable coefficient of friction.
If my attempt at repair doesn't work out, I will update on here but I am optimistic!

[singleminded]

My 1932 clutch stops have a 10mm approx recess in them, at least the spare ones do. The material sticks out about 3/16"..

[VicYouel]

Brian

I used the previous stock example to have some more made..... trouble is I did not have the metal bit in which to try it..... the original material was some sort of red stuff. This brake material should last so I would go for the shortened solution.
Vic

[Brian Petheram]

Time for an update. The spring has been fitted and seems to have done the trick - the adjusting nut has far fewer turns in and the pull is much lighter when the clutch is adjusted. Of course this is on the bench at the moment but it is definitely much better in terms of feel.
The only job (that I know of!) before I put the cover on is to sort the clutch stops - one of the pads was absent. I have received a stick of clutch stop material from club spares. Fantastic service from Vic Youel - it arrived the next day, thanks!
On searching this forum about clutch stops it seems they are glued in the holder with araldite - the material supplied is actually a bit smaller in diameter than the holder so I'll need to use plenty. The recess the material fits in is only about 3mm deep which seems a bit shallow to me given the sideways loading. Also on a previous thread a distance of 13mm from the back of the screw is recommended. This seems a lot to me as the remaining one (which I will replace so they both match) is only about 2mm proud of the housing, so about 4mm overall. My thinking is to cut them so that only about 3mm is proud of the housing . Making them short would reduce the leverage forces trying to pull them out (although I guess they would be pretty minimal unless the clutch is dragging) but of course making them longer would be better for allowing for wear - no idea of how fast that would be . As ever I'm open to guidance or suggestions.
Cheers,
Brian

[Brian Petheram]

Brilliant service from Chris - spring has arrived. Now to see if it all works...

Thanks for the timely suggestion about the back plate - it does seem OK but well worth checking. Other ideas welcome.

[singleminded]

If you clutch has a back plate it may be worth checking that it is flat. Though my 1932 clutch is slightly different it started slipping because the back plate had worn convex, i thought at first it had bent.
This is just a thought about the slipping and while it is apart it's worth checking..

[Brian Petheram]

Thanks to Vic and Graham for your replies. I have been in touch with Chris Odling and he does have some clutch springs so it looks like I am sorted (assuming the spring really was the problem ).

[shorrog]

Try Chris Odling he did have some last year when I purchased one.
Graham

[VicYouel]

I hope you make progress with this and once you investigate making a new spring I think the club might be interested in joining with you to get some made..... so would be grateful if you would keep me informed
Vic

[Brian Petheram]

Hi all,
my new to me 1927 Model 5 has the single spring clutch. It has an incredibly hard pull at the lever and also manages to both slip and drag.
On removing the outer chaincase I found the spring adjusting nut done up so tight that I needed to get a spanner on the mainshaft nut under the spring and then shock it the adjusting nut loose with hammer blows on a foot long ring spanner! Along with the excessive slack on the primary chain this makes very worried about the competence of the previous owner...
Anyway I now have removed and inspected all the plates and they seem to be in good condition with the plain plates flat and the corks well proud although there are some minor corrosion marks on the plates. Whilst I am open to other suggestions, my suspicions centre on the spring as I have had similar symptoms on other clutches caused by a weak spring. I have measured the free length as 55.5mm (2.185") - is this correct? I would buy a spring anyway if it were available in the shop but it seems only the 6 spring type is stocked so I may have to get one made - any suggestions on a source? I will have to get some clutch stop material from the shop anyway as one of the "buttons" was missing - another black mark against the previous owner.
As I said above, any other suggestions are welcome and thanks for reading. As a new member I am looking forward to meeting some of you at the Bristol Show this weekend.
cheers
Brian