Greetings Posted May 11, 2006 Report Share Posted May 11, 2006 Sorry if this is repeated, couldn't be bothered to read the whole thread. Not quite sure how the driveshell bearing looks like in your hub, but you might need to use a much stronger and wider one (preferably a needle bearing). This is because when all 3 pawls engage, the forces are counterbalanced, whereas with one engagement, the driveshell will be forced against the opposite to the pawl side of the bearingWell, that's the theory at least. Good luck Quote Link to comment Share on other sites More sharing options...
Ashley Smith Posted May 11, 2006 Report Share Posted May 11, 2006 Why havent hope tryed this yet if its such a good idea?i had a prototype pro2 that ran on one pawl at a time and gave 72 engagement points, this just skipped constantlythen we moved on to the good design which is now used in the pro 2's where two pawls are offset to the other two to give 48 epsash Quote Link to comment Share on other sites More sharing options...
Mr Motivator Posted May 11, 2006 Author Report Share Posted May 11, 2006 I said it was the Echo hub that had singular engaging pawls, well it was the Zoo! hub, hence why they never released it propperly I guess.However, there DOES need to be a problem, aswell as being something to do for myself this will be a college project, so I need something to say at the end what could be improved.. This is perfect you see ;PI'll still go ahead and make it. It's still just going to be pretty cool coasting with 84 clicks, even if I dont end up using it for trials, that's what the King wheel is for. Quote Link to comment Share on other sites More sharing options...
guineasmithpig Posted May 11, 2006 Report Share Posted May 11, 2006 (edited) that second drawing looks MUCH better! you need to have at least 2 pawls engaing at once (especially in trials) as force applied, lets say, at 90 deg to the pawl will just push the driveshell into the axle/sideload the bearings by pivotting around the engaged pawl. i think i once measured up and reckoned u could fit another pawl between each of the 3 pawls in a standard XC driveshell, meaning 2 pairs of 3 pawls. double the engagement with the usual hope reliability (most the time). this may also save you some time and expense. also, if you are making the shells from scratch, have a look at integrating leaf springs instead of compression springs as i think these would be much more reliable than the standard hope ones. they seem to get squashed or bent a lot in my experience well, now that i've given you all my ideas (which i have neither the time nor resources to impliment) i hope (geddit?) you get somethin sorted. just don't expect it to work the first second or 15th time! the tolerances required to match the pawls up to hopes precision machined ratchet rings will almost certainly require the same calibre of tooling as they use! or some serious CNC or manual skills. but again, best o luck!smithyPS. it'll be far from perfect. just a hunch! Edited May 11, 2006 by guineasmithpig Quote Link to comment Share on other sites More sharing options...
Mr Motivator Posted May 11, 2006 Author Report Share Posted May 11, 2006 well, now that i've given you all my ideas (which i have neither the time nor resources to impliment) i hope (geddit?) you get somethin sorted. just don't expect it to work the first second or 15th time! the tolerances required to match the pawls up to hopes precision machined ratchet rings will almost certainly require the same calibre of tooling as they use! or some serious CNC or manual skills. but again, best o luck!smithyPS. it'll be far from perfect. just a hunch!Well, I'll lathe it into the general shape, drill the two big holes through it, then whack it in the cnc machine, draw it on cad again, click GO and sit back and watch it machine away some pointy bits for the sproket.I'll probably have to start the pawl seats manually on the mill, and tidy them up on the cnc Quote Link to comment Share on other sites More sharing options...
guineasmithpig Posted May 11, 2006 Report Share Posted May 11, 2006 u'll need to ream the pawl seatings out to be smooth enough. don't think straight milling cutters will be up to the task. i'm guessing hope grind theres out. also (and thise will surely help loads) machine out the slots BEFORE you turn that end down to size. trying to mill onto the sides of a pre cut cylinder will be useless as the cutter will flex and you'll be miles out. doing this in the CNC miller will be much better. infact, do the whole seating section with CNC, as you'll never get the accuracy manually! and then turn that end to size. then blitz the seats out with a dremel to remove and flash and polish the seats out. Quote Link to comment Share on other sites More sharing options...
Mr Motivator Posted May 11, 2006 Author Report Share Posted May 11, 2006 u'll need to ream the pawl seatings out to be smooth enough. don't think straight milling cutters will be up to the task. i'm guessing hope grind theres out. also (and thise will surely help loads) machine out the slots BEFORE you turn that end down to size. trying to mill onto the sides of a pre cut cylinder will be useless as the cutter will flex and you'll be miles out. doing this in the CNC miller will be much better. infact, do the whole seating section with CNC, as you'll never get the accuracy manually! and then turn that end to size. then blitz the seats out with a dremel to remove and flash and polish the seats out.I know how to mill Quote Link to comment Share on other sites More sharing options...
guineasmithpig Posted May 12, 2006 Report Share Posted May 12, 2006 gravy. just that i've seen it soooooooooo many times before. think i probs done it meself before! get to the last process of a project and think 'CRAP!!! thats never gonna work now!' hahakeep us postedsmithy Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.