fae_alba Posted April 27, 2019 Posted April 27, 2019 Can anyone give some good tips/tuts on modeling a set of gears like the image below. The goal is to 3D print them so the tolerance of the teeth need to be fairly good. Quote
Hash Fellow robcat2075 Posted April 27, 2019 Hash Fellow Posted April 27, 2019 In an art class we had assignment to illustrate a nursery rhyme and I was doing "Hickory Dickory Dock". I asked the teacher what the formula was for drawing accurate gears but he just sort of stared at me. Paul, i think the starting point is to find three circles that will fit together like that (without teeth) and that all have a circumference that is an integral multiple of some small distance. That is the hard part. Modeling the teeth will be easy if we can figure that out. Maybe there is a formula? Live Answer Time at Noon CDT, btw. Quote
Hash Fellow robcat2075 Posted April 27, 2019 Hash Fellow Posted April 27, 2019 hmmm... https://khkgears.net/new/gear_knowledge/gear_technical_reference/calculation_gear_dimensions.html Quote
fae_alba Posted April 27, 2019 Author Posted April 27, 2019 2 hours ago, robcat2075 said: hmmm... https://khkgears.net/new/gear_knowledge/gear_technical_reference/calculation_gear_dimensions.html Oi, there's math in that link! Quote
Hash Fellow robcat2075 Posted April 27, 2019 Hash Fellow Posted April 27, 2019 The math for two gears woudln't be bad but I'm not sure how you do it for three, especially three that are not in a straight line. There must be a way... Quote
Wildsided Posted April 27, 2019 Posted April 27, 2019 if you could find a view from directly above you could rotoscope the teeth so they're proportioned properly and then do a lot of copy/paste rotate. then you could scale them to size. If that makes sense. Sorry if it doesn't. Quote
Hash Fellow robcat2075 Posted April 27, 2019 Hash Fellow Posted April 27, 2019 Lessee... the outer circle will have a radius equal to the radius of the inner gear plus 2x the radius of the intermediate gear... Quote
fae_alba Posted April 27, 2019 Author Posted April 27, 2019 My plan is to have the inner gear ring mounted to a plate so that it performs as a spinning ride deck, ala mad hatters tea party ride. I'm modeling the bed and inner plate that will mount to the tea pot and motor. I'll include pics when I get home Appreciate the assistance ..makes the heavy thinking a bit easier! Quote
Wildsided Posted April 27, 2019 Posted April 27, 2019 Don't know if this would make things easier but according to this simulation site http://www.thecatalystis.com/gears/ A 'sun' cog with 24 teeth would need 3 'planet' cogs of the same size with the same number of teeth which would save modelling. Quote
fae_alba Posted April 27, 2019 Author Posted April 27, 2019 1 hour ago, Wildsided said: Don't know if this would make things easier but according to this simulation site http://www.thecatalystis.com/gears/ A 'sun' cog with 24 teeth would need 3 'planet' cogs of the same size with the same number of teeth which would save modelling. Now that is a nice site! Might even be able to use that as a screen grab/rotoscope Quote
Hash Fellow robcat2075 Posted April 27, 2019 Hash Fellow Posted April 27, 2019 that's a great find! Quote
Wildsided Posted April 27, 2019 Posted April 27, 2019 I used a screen grab from that site to roto a 1-inch diameter 24 tooth cog. It's not got bevelled edges or anything so I don't know how suitable it would be for 3d printing but the teeth intersect properly. Gear.mdl Quote
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