Power casters move boats, campers, RVs and cargo trailers from one spot to another on driveways and lots, or when no vehicle with a hitch is available. A variety of power caster versions on the market are sophisticated and expensive. They are too much for occasional use when moving a boat or camper around at a summer home. This DIY power caster is an easy and rewarding build.
This unit is based on a hand truck, with pneumatic tires and an industrial reversible 115 VAC gear motor with 1/3 horsepower, powering a single, 60-tooth, #35 chain sprocket, 12.5-inch-diameter general purpose minibike drive wheel. The final drive speed will be about two feet per second, which is accomplished with a 24-tooth sprocket on the motor, assuming a 90 rpm gear motor.
Besides the major components above, you will need a four- foot length of #35 chain with coupling links and half links, a double-throw, double-pole switch and a push-button switch, both rated for 20 amps at 125 VAC. Final items are a hitch ball to fit to the trailer and three feet of two-square-inch steel tubing, eight one-inch U-bolts with plates and nuts and a four-foot section of quarter-inch-thick by three-inch-wide flat steel plate. Most items are available on the Web from discount industrial supply houses.
Cut an 18-inch section of square tube with a 45-degree angle on one end. Weld or bolt this section to the middle of the baseplate of the hand truck where it meets the frame. Also drill holes for the hitch ball in two four-inch-long sections of the flat steel plate with a hole saw. Weld the two pieces in place on top of the 45 degree angle so the ball will be closer to the top handle. .
Cut two eight-inch sections of flat plate. Drill centered holes at the ends for two of the U-bolts for each section. These will mount it to the top side of the hand truck frame tubing. Also drill holes on each side of the two eight-inch pieces to secure the drive wheel axle with the U-bolts. The wheel should be located so the tread is about two inches up from the hand truck axle. Use the remainder of the flat plate to mount the motor on the top side of the frame, just above the wheel so that the motor sprocket is aligned with the wheel sprocket. Install the chain and use links to make it taut. Wire the reversing motor leads to the double throw switch. Wire to the push-button switch and add a shop-grade line cord with ground.
Wheel the power caster to the trailer. Lower the trailer on the hitch ball and latch. Push down on the handle until the drive wheel contacts the ground. The double throw switch controls forward-reverse, and the push button acts like a dead-man’s switch. This unit takes the grunt work out of occasional trailer moves.
