Brick Rice Transplanter MOC: Tracks, Arms, Seedling Tray
The short version: this rice transplanter MOC uses roughly 2,200 parts to produce a tracked rice transplanter about 32 cm long. Plan on around 8 hours of building and a budget of about 430 RMB, with a medium-to-advanced difficulty rating. The highlight is the transplanting arm assembly that swings up and down, paired with the seedling tray, which together give the model its unmistakable farm-machinery character.
Rice transplanters are the advanced class of agricultural MOCs. A tracked chassis, a wide seedling tray and rows of transplanting arms make the structure far more involved than an ordinary tractor, and that complexity is exactly what makes it such a good showcase for mechanical detail. This tutorial walks through the build in four steps so you can assemble a green machine that genuinely "plants" using standard Technic parts.
Step 1: The Tracked Chassis
The chassis has to run on tracks if the model is going to hold the right proportions. Wrap track links around two pairs of drive sprockets and idler wheels, with a tensioner wheel in the middle to adjust slack. Turn the crank handle and the tracks should roll forward and backward smoothly. The tooth pitch on the drive sprockets needs to mesh tightly with the teeth on the inside of the track links — too loose and it slips, too tight and it binds. Build one set on each side, then join them with cross beams into a single unit, leaving a flat mounting surface on top for the transplanting mechanism and seedling tray.
Step 2: The Transplanting Mechanism
This is the heart of the machine. Build the transplanting arms as a linked group that swings up and down: a side handle drives a crank-and-rod linkage that moves a row of 4 to 6 arms, mimicking the lift, plunge and return rhythm of real planting. Each arm is made from a Technic arm plus a short axle, with a green round plate clipped at the bottom to act as a seedling; when the arm reaches the bottom of its stroke it leaves the seedling on the field surface. Keep every connecting rod the same length and line up the pivot points, otherwise the arms will swing out of sync and the whole motion will look wrong. If you already understand gear trains, you can go further and link the track drive to the planting motion.
Step 3: The Seedling Tray
Mount the seedling tray above the transplanting mechanism as a wide platform, with walls around the edges to stop the "seedlings" falling out. It should hold several dozen green round plates laid flat. Make the rear section a hinged panel that lifts up, which makes it easy to demonstrate loading and refilling. Add handrails along both sides in orange or yellow to contrast with the green body and recreate the visual layering of the real machine.
Step 4: Driver's Position and Details
Finish with the operator area: a single front seat, a steering wheel and a small control panel, plus a canopy on top so a minifigure operator sits in convincingly. For detailing, keep the body predominantly green with a black chassis underneath, add farm-style stickers along the sides and fit a tow hitch at the rear. The finished model measures about 32 cm long; place it beside a rice paddy scene or next to a tractor MOC and you have a complete spring ploughing diorama.
FAQ
Q: How do the transplanting arms move?
A: A side handle drives a crank-and-rod linkage that moves a row of 4 to 6 transplanting arms, reproducing the lift, plunge and return rhythm. Each arm carries a green round plate at the bottom as a seedling, and leaves that seedling on the field surface at the end of the downward stroke.
Q: Is this a hard build?
A: Medium-to-advanced. The main challenges are keeping the connecting rods the same length, aligning the pivot points, and getting the track tension right. Experience with Technic gears and linkages helps a lot, so build it in stages rather than rushing.
Q: Is it suitable for beginners?
A: Not really a beginner project. Build two or three ordinary farm or construction vehicle models first before taking this on. If you want practice, start with a simplified rice transplanter version or a tractor MOC, then come back to this one once you are comfortable.
Q: How is it different from a brick tractor MOC?
A: A tractor is mostly about the engine cover and tow hitch, so the structure stays simple. A rice transplanter adds three extra systems — the tracked chassis, the transplanting mechanism and the seedling tray — which means more parts and a longer build, but far more mechanical play value.