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Thanks, this is very helpful. You are correct that I'm in the "design for manufacture" phase... and it's somewhat overwhelming. With regards to the specifics,

Thanks, this is very helpful. You are correct that I'm in the "design for manufacture" phase... and it's somewhat overwhelming. With regards to the specifics, here's one of the parts - https://i.imgur.com/1oqjQ7r.png https://i.imgur.com/1oqjQ7r.png - basically a flat (bottom) piece that can be laser-cut and a cylindrical clutch-like bit with a cutout for a "flat-leaf" bolt. The idea is to pass a rotating axis through the central hole and to affix the part to it to have it rotate with the axis. Needs to be all metal as it's a high-temp (BBQ) setup.

maicro 3y ago
Still not sure the general layout of this - is the end goal to have some form of rotisserie that has multiple rods, each of which rotates about their own axis in addition to the primary axis, so that the food is cooked more evenly? If so, be careful about your gear ratios - you don't want the rotations to match up every time, otherwise you won't actually gain anything from the secondary rotation axis (the same side of the food will be rotated down closest to the flame on every rotation). I'd have to do the math / play with it, but off the top of my head I'm thinking as long as the gears aren't the exact same number of teeth you'd had full secondary rotation after [larger number of teeth] rotations. That being said - to make that part, if concentricity isn't _critical_, you could easily split that into two sections. As you said, the bottom flat section would be laser cut (/water jet) out of sheet material; you could add some mounting holes around the central axis, then threaded holes in the rod mounting boss (or through holes for very long bolts and nuts, but that's better for prototyping with limited tapping/etc. capabilities).
- huhtenberg 3y ago
  > Is the end goal to have some form of rotisserie that has multiple rods, each of which rotates about their own axis in addition to the primary axis, so that the food is cooked more evenly? That's exactly it. Well-deduced. Secondary rods are just skewers. > If so, be careful about your gear ratios. Yep, got that covered. The gear ratio is 16/11.
  - maicro 3y ago
    In that case, you might want to look at a mechanism called a "planetary gear set" for inspiration - I don't know if it's common for the rotation of the "planet" gears to be harnessed to drive something other than a synchronized output shaft, but it's still the same basic mechanism.
    - huhtenberg 3y ago
      Planetary gears need a stator. It can be done, i.e. have the gear box attach to the side of the barbeque, but that'd be way more expensive to fabricate and it will be BBQ-specific. Here however - one inner gear, one spur gear and a rotating shaft and that's it. Stupid simple and it works.
maicro 3y ago
And one final message for now... First, once you get several projects under your belt, you should start integrating "design for manufacture" into your main design process - that way you don't waste time designing some custom part, then searching for that specific item / someone to make it, when with some minor adjustments and off the shelf part would be _significantly_ cheaper and readily available. Second, for designing with available parts, I love McMaster-Carr - they have great specs and drawings for just about everything, and 3D models you can import into most CAD software for most parts as well. They are more expensive than other sources for most individual parts, but the confidence you have with ordering from them is great, and for one-offs and prototyping they're invaluable.

maicro 3y ago

Still not sure the general layout of this - is the end goal to have some form of rotisserie that has multiple rods, each of which rotates about their own axis in addition to the primary axis, so that the food is cooked more evenly? If so, be careful about your gear ratios - you don't want the rotations to match up every time, otherwise you won't actually gain anything from the secondary rotation axis (the same side of the food will be rotated down closest to the flame on every rotation). I'd have to do the math / play with it, but off the top of my head I'm thinking as long as the gears aren't the exact same number of teeth you'd had full secondary rotation after [larger number of teeth] rotations. That being said - to make that part, if concentricity isn't _critical_, you could easily split that into two sections. As you said, the bottom flat section would be laser cut (/water jet) out of sheet material; you could add some mounting holes around the central axis, then threaded holes in the rod mounting boss (or through holes for very long bolts and nuts, but that's better for prototyping with limited tapping/etc. capabilities).

huhtenberg 3y ago
> Is the end goal to have some form of rotisserie that has multiple rods, each of which rotates about their own axis in addition to the primary axis, so that the food is cooked more evenly? That's exactly it. Well-deduced. Secondary rods are just skewers. > If so, be careful about your gear ratios. Yep, got that covered. The gear ratio is 16/11.
- maicro 3y ago
  In that case, you might want to look at a mechanism called a "planetary gear set" for inspiration - I don't know if it's common for the rotation of the "planet" gears to be harnessed to drive something other than a synchronized output shaft, but it's still the same basic mechanism.
  - huhtenberg 3y ago
    Planetary gears need a stator. It can be done, i.e. have the gear box attach to the side of the barbeque, but that'd be way more expensive to fabricate and it will be BBQ-specific. Here however - one inner gear, one spur gear and a rotating shaft and that's it. Stupid simple and it works.

maicro 3y ago

And one final message for now... First, once you get several projects under your belt, you should start integrating "design for manufacture" into your main design process - that way you don't waste time designing some custom part, then searching for that specific item / someone to make it, when with some minor adjustments and off the shelf part would be _significantly_ cheaper and readily available. Second, for designing with available parts, I love McMaster-Carr - they have great specs and drawings for just about everything, and 3D models you can import into most CAD software for most parts as well. They are more expensive than other sources for most individual parts, but the confidence you have with ordering from them is great, and for one-offs and prototyping they're invaluable.