If you want it to mesh nicely, easiest way is to make two - first one undersize, put it in, measure backlash, then cut the second one with appropriately thicker teeth. Only problem with this is, calculating the tooth thickness won't be so easy given the situation (unless you take the whole thing apart, which seems extreme). Or have someone cut the teeth for you, it's easy, should not cost very much. Or draw it up big, shrink to size, hand grind a cutter to match. A lot of pinion wire (the name for teeth cut into a bar) is done drop-tooth, maybe the stock pinion wire pavt (I think ?) linked to is already that way, check the dimensions on their 11 tooth wire. You can draw it up if you want to see.Įasy to do with a generating process like hobbing or shaping but I've never tried it with space cutters. The limit to this is how pointy they will end up. That moves the base circle down and the involute way out, so you get pointy teeth but they are not undercut. Standard method in this situation is to cut 11 teeth on your 12 tooth blank. Not if you want it to work right, anyhow. To eliminate undercut you can make the pressure angle biggerAnd take the arm out and recut the rack so they match ? You can't just willy-nilly change the pressure angle on one half. If he has a CNC mill with a fourth axis he can mill the cutter in the soft state from A-2 or D-2 with tapered cutters to get the relief and have it 's not that bad but still a PITA.īut he says he has time rather than money to burn on this project, so why not? Of course, if I care to invest the effort to draft it up, I can just as easily make a single lip or maybe 2,or 3 flute involute cutter and save the fucking around the Sunderland process entails.īut that option is probably not available to him, unless he can hire a wire shop in his area, and it'll be one pricey custom he's going to use a grand total of once. I'd personally do it with a home made rack cutter and the Sunderland process, but I can make a rack cutter easily.I have a wire EDM with a rotary axis on it. So making a cutter for a single shaft is a PITA but still probably the best way forward. Sadly, I doubt he will be able to find a 30 deg PA cutter for 12 teeth in his desired module. In his first post he said it was 60 degrees included angle which makes a PA of 30 deg.įor a highly stressed gear with very few teeth this makes sense, creating a tooth with a stronger root as you point out. Since he has the rack he can just measure the flank angle of a tooth it will obviously be the same as the pressure angle.
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