NB:- The actual tromel shown in the photo was printed out half size by way of a demo and it's holes are therefore probably too small for practical use with soil. If you do want to make this as a half size demo I've included a file which will mount a 3 volt N20 motor through the hopper into the end of the auger.
The enclosed files are the majority of parts you'll need to build a tromel for seiving the rocks out of garden soil for your R/C construction site. The parts included are as follows:-
- The Hopper. Has a 7mm hole in the end to provide an easy way of powering the drums. Dirt is dumped into the hopper by your r/c excavator/loader/whatever.
- The auger. This has a 6mm D shaped hole in the end to attach a 12v gear motor and moves the dirt from the hopper to the start of the sieving drums.
- A set of optional gears to provide an alternative way of powering the drums if you don't want the motor hanging off the end.
4 Drum 1(end driven or belt driven only). A fine mesh drum (6mm holes) which let only the soil through.
- (Drum1(end driven belt driven or ring gear driven) as above but this variation of the first drum has a ring gear on the end for those who want to power it that way.
- Final drum with 12mm dia holes.
- Support wheels. Depending on how you want to mount the tromel you may find these wheels useful in providing additional support for the drums.
- An overview of the entire assembled tromel.
- A set of Grizly Bars to pre-filter any rocks that are too big for the auger to handle.
- An N20 motor mount for half scale demo use.
The largest part (the hopper) fits easily on any 200mm printer and while scaling it down could prevent it sieving actual soil there's nothing to prevent you scaling it up apart from printing time, filament use, and drive motor attachment considerations.
Overall dimensions are around 600mm long (24"), drum diameter approx 95mm, height approx 125mm (5"), and front to back 160mm (6.5").
Just about any small (25mm/1 inch) gear motor in the 50-100 RMP range can be used to power it.
What's not included? A frame to mount the entire assembly on. The frame design is up to you and could vary wildly depending on what space you have around the installation and what access for your r/c vehicles you need to provide.