Metric threading gears - 10EE square dial

I took time off from the drudgery of rebuilding my 10EE to do something I enjoy: making gears. I looked at all the pitches capable on the gearbox and realized that two stud gears, a 45 and 50, will provide essentially every useful pitch, save one, .8 mm. So instead of duplicating every stud gear that Monarch and ZK offer, I only made the 45 and 50 right now. I can always make another stud if I need. The gears are helical because I got a brand new,super fine quality Class AA Gleason hob off ebay for only $25 that fits my Barber Colman #3, but it is a wacky pitch, 34.05 Dp, slightly smaller than the standard 32 pitch for the change gears. Obviously, except for the original purchaser of the hob, there isn't much demand for a 34.05 Dp hob. By making the gears helical the diameter of the gears enlarges based on the helix angle. I simply duplicated the diameter of the 32 Dp gears.

I made two sets, one for me and one for EverettEngineer, since he was nice enough to give me the massive T5 transformer to use with my Parker drive. The crazy thing about gears is that each set of 3 gears is less than $10 of 12L14, but as ZK and I point out, gears are an expensive hobby. A gear shop would charge upwards of $1000 for these three gears.

Beautiful work John. Can't wait to give 'em a try.
I've been using my old Logan for metric gears and it will be so nice to use the 10EE instead.
Mark

bll230 said:

A gear shop would charge upwards of $1000 for these three gears.

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Brilliantly pragmatic approach, making only the ones that covered nearly the full range. Nicely executed as well. VERY !!!

Even so, if that $1,000 is realistic for an arm's-length third-party shop's fees (and it seems it is) that nets to not a great deal of savings vs ZK's price for the higher-count full set as straight-cut spurs.

Not that I'd class it as "typical", but what with transport, I spent about five times that to get rather good Metric threading coverage.

The HBX-360-BC that enabled it does want right about double the electricity budget of a 10EE, and about 30% more floorspace as well, though!

bll230 said:

[...] every useful pitch, save one, .8 mm.

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Nicely done! You're also missing 1.75mm, the standard thread pitch for a 12mm bolt. If I deduced the ratios correctly, a 35 tooth stud gear on gearbox setting 8 would yield 1.75mm (and also produce 3.5mm on gearbox setting 4).

Don, you are right with your numbers, except a 35 tooth is physically too small for the keyway so it needs to be a 70 tooth. What I am missing is a 40 tooth for .4 and .8, and a 75 tooth for .35, .7, 1.75, and 3.5. Thankfully the time it takes to make the blanks for the stud gears is minimal, the 127s took a while.

You'll likely need to deal with thrust concerns, as well. Short term, you'll be fine. But it will affect them down the line. It always amuses me when people react so negatively to the price of a full Kit. Personally, I think I did a pretty damn good job keeping them as affordable as possible, given just exactly what goes into each gear, and Kit. Some people just see a lump of steel and feel like that's worth $30 and not one cent more. We cannot please everyone.

I thought of that, but the sine of 20 is only .34, so only a 34% thrust load, and the reverse shaft is in one of the New Departure preloaded double row angular contact bearings since it already has to take the thrust loads from the internal headstock helical gears which are probably 20 degrees as well.

The idler bearings are way oversized for the load applied and they have pretty good separation in the idler, so I think they would still spec out as conservative. From my model helicopter experience, it is amazing how much thrust load a single 10 mm main shaft bearing (Chinese, of course) can take and still last maybe 100 flights with no notchiness.

You are right on pricing, when someone asks me about a custom helicopter gear and I tell him I'll make it for $100, 9 out of 10 times I'll never hear back. People are used to $10 for a mass produced molded Chinese gear that wobbles. The few people that pay me are then amazed how much smoother their helicopter is with a cut gear that runs true.

Edit: I was thinking sine, and I wrote cosine and then blindly punched the wrong button on calculator. And I hadn't even been drinking wine when I wrote it. Correct now.