The question I would as my self, after building up and turning down the ball groves is dose it engage better now than before ? if it dose I personally would not touch the sprockets.
Most gears/sprockets are usually made from blanks and machined or broached then case hardened by several methods. To process anneal you need to heat to cherry red then quench in oil or water. Then to case harden a gain heat to cherry red and dip into graphite powered
Or maybe have a scavenge around a scarp/salvage yard for a similar and possibly longer sprocket and then turning down the free, none engaging end to get it to the right length.
Sintered Carbide tool tip will cut most types of ,materials from plastics to hard steel at a multitude of speeds with the added benefit of polishing at the same time as cutting.
I've had a look at the photo and this type of gear/sprocket is difficult to draw never mind manufacture the dividing head would need to be a driven head and calculations will be needed to obtain the correct rotation/length ratios. If your going to do it that way I would advice experimenting on a few bits of scrap first.
| >>I've decided to see what I can do to resuscitate the existing parts, | >>starting with the ball bearing slots. I've built the worn edges up | >>with Stellite TIG filler, turned the surplus off the outside (no prob | >>with a carbide tip) and cleaned out the slot itself with a die | >>grinder. I'm very pleased with the results, wondering now whether to | >>have a go at the teeth tips. These would need careful setting up with | >>an indexer in the tool grinder after building up, I reckon I can do it | >>but I just wonder how strong the teeth will be. The existing body is | >>some fairly tough, heat treated steel, too hard to file but | >>machineable with carbide. | >>I know this isn't an engineering forum, but there may be someone here | >>who reckons they know enough to comment? | >>
| >>Pic of the pinion at | >>
| >>I chose the view badly, you can just see one of the angled slots at | >>the bottom. | >>it's around 90mm OD, 36 teeth. | >>
| >>Cheers | >>Tim | >
| >Tim, | >Without knowing how this all fits together as a whole can you just get | >away with milling or grinding the original teeth back to get a second | >life? | >
| >Seems a simpler solution to me but not knowing the mesh / clearances | >etc............................................ | | John | | I've thought about that one, there are a few potential problems. | One is it's an acute angle at the root of the teeth, so that'll mean | dressing up a grinding wheel or finding/grinding a special milling | cutter to do the job, & I'm not sure whether HSS will touch it. OK, if | I build up the teeth I'll still need to dress up a grinding wheel to | clean them up. My original idea was to do just what you suggest with | some careful filing. Not a chance, a file won't go near it. | The real snag is likely to be that the teeth will be 1mm or so further | back on the body, & that *might* lead to problems with the meshing | etc. It might not, I'm not sure but it's quite a bit of work to do to | find that the owners have to go out & spend nearly a grand on new bits | after all! | Thinking about it some more, I suppose I could shim up the engine side | dog by an amount similar to anything I take off the pinion teeth. | Can't see why that wouldn't work. | My worry over building the teeth up is that the welding might make | them brittle behind the weld as it's obviously steel with a reasonably | high carbon content. | | Thanks | Tim | | Dutton Dry-Dock | Traditional & Modern canal craft repairs | Vintage diesel engine service