OK guys, let's have some honesty here. Am I the only one who always has a hell of a time trying to fit SP1/1 bronze spring claws to the springs properly and get them both snug and parallel? I have just spent a small fortune on buying a set of 4 new ones and I have tried them on a variety of different springs - early slimline Comet ones, Standard Rapide ones, Pettefords and sidecar Pettefords. As most will know, I am not averse to a little fettling, but the spring claws seem to me to be unfit for purpose. They don't even get close to parallel! More material needs to come off the claws than is already on there to get them anything like close to correct.
Interestingly, the larger claw ID is machined 11/32 dia and the smaller one 1/4 dia: why would this be? And why are they machined parallel to the face when the spring has a helix angle around 5 to 6 degrees?
Now turning to the springs. Should not the first/last coil have been softened and bent to reduce the helix angle to zero before grinding it off flat? None of mine are (just a small ground flat).
It seems to me that the only way to get these right is to make my own; and make them much thicker so they can be machined parallel after being fitted to the spring; the last operation being to drill and tap the 7/16 BSF thread. There again, who's tried machining a lump of metal attached to a spring? Interesting ain't it!
All of a sudden, Thorntons seem to be a better bet despite the price. If only Laney and Dave Molloy could come up with a proper solution to prevent 'cocking'. And that's another story for another time.... Sigh!
What we need here is an expert. Frank, where are you?
Peter B
Bristol, UK.
Interestingly, the larger claw ID is machined 11/32 dia and the smaller one 1/4 dia: why would this be? And why are they machined parallel to the face when the spring has a helix angle around 5 to 6 degrees?
Now turning to the springs. Should not the first/last coil have been softened and bent to reduce the helix angle to zero before grinding it off flat? None of mine are (just a small ground flat).
It seems to me that the only way to get these right is to make my own; and make them much thicker so they can be machined parallel after being fitted to the spring; the last operation being to drill and tap the 7/16 BSF thread. There again, who's tried machining a lump of metal attached to a spring? Interesting ain't it!
All of a sudden, Thorntons seem to be a better bet despite the price. If only Laney and Dave Molloy could come up with a proper solution to prevent 'cocking'. And that's another story for another time.... Sigh!
What we need here is an expert. Frank, where are you?
Peter B
Bristol, UK.