Sturmey-Archer SW Drei-Gang-Naben: Unterschied zwischen den Versionen

[[Datei:Pawl-ring-pawl-socket-cutoff.jpg|right|Schneiden eines Schlitzes für eine Blattfeder]]Using a cutoff wheel on a Dremel tool, make some shallow cuts at the bottom of the pawl sockets as shown. cutoff wheel The depth should not be too great, perhaps around 1/16th of an inch or so. Also, be careful to keep the slot as short as practical so as not to weaken the pawl ring (L11) too much. Next, some suitable spring material must be scavenged to place in these slots. I found that a camera wind-lever spring worked well for this purpose, but anything similar will do — look for flat, spiral shaped springs in old mechanical clocks, cameras, toys, etc. The final spring configuration I arrived at was about 1/16th of an inch wide and around 3/8ths of an inch long, providing firm springing action against the bottom of the pawls. If I do this again, I might try something a bit more flexible such as the film-chamber pressure plate from the same junk camera. Any thin, flat spring that can be bow-shaped will probably work. pawl ringMake sure that whatever spring material you use, your Dremel cuts are deep enough to allow the springs to be totally recessed. In operation, the large pawl retaining washer (L13) and the thrust spring (L15) will keep these pawl springs in place.[[Datei:Paw-ring-improved-pawl-sockets.jpg|left|Blattfeder in Sperrklinkenbuchse]]

Assembly is a bit tricky because when the right-hand ball ring (L14) is placed over the pawls, the springs tend to push against the retaining washer and then pop out. I solved this problem by assembling the driver, spring, and ball ring all at the same time, and then assembling over the installed pawl ring, washer, and pawls. The thrust spring helps to keep the new pawl springs from shifting out of their grooves.

This modification has worked well with old, worn pawls and produced an assembly that virtually guarantees all three pawls will be properly engaged. The low-gear pawls would also benefit from this technique, and the pressed steel retainer on the end of the planet cage would retain the springs well. However, assembly of the completed internals into the hub shell might be very difficult to impossible — proceed at your own risk. Since the low-gear pawls are more reliable, springs are probably not needed on this side.

While sprung pawls may ultimately be the best practical fix, they do have one drawback. The hub will no longer be "silent" when coasting. In fact, the spring arrangement I have described gives a rather "bright" ticking sound similar to the AW's.