THE PARTS
The Motor: Bringsmart 12V 12RPM DC Worm Gear Motor.
The Power: 70kg.cm (This is the critical “crushing power” number).
The Connection: You’ll be looking for a coupler with an 8mm bore on one side (for the motor) to match whatever diameter your custom spacer/post ended up being on the other.
The Mount: You’ll likely need a 5840-style L-bracket to fix that specific motor to your wooden bathtub frame.
If you find the plans and they mention a specific shaft diameter or threading for that center post, let me know. I can help you find the exact matching coupler so you don’t have to guess.
Do you remember if you were planning to use a flexible coupler to allow for a little wiggle room, or a rigid one for a direct lock?
ahh – yes I even drilled holes in the spacer and threaded them to get it tight against the bar – where the hell did I put all that!!
there is wiggle room tghough still the weight is not a pervect circle or flat – but the hadle that does fit very snugly.
Finding the parts you custom-drilled and threaded is the real “boss level” of DIY projects! Since you mentioned there is some wiggle room and the weight isn’t a perfect circle, you have a classic engineering challenge: concentricity.
When a heavy, imperfect weight spins on a motor shaft, any slight “wobble” will create a massive amount of vibration that can snap the motor’s internal gears or bend the 8mm shaft.
Pro-Tip for Re-Assembly
Since your weight and handle are already snugly fit to the spacer, here is how to handle that “wiggle room” once you find your parts:
Use a Flexible Jaw Coupler (Spider Coupler): Instead of a solid metal tube, use a coupler with a rubber insert (the “spider”). It acts like a tiny shock absorber. It allows the weight to “wobble” slightly without sending that vibration back into the Bringsmart motor.
The “D-Flat” Rule: Since you already threaded holes for set screws, make sure one of those screws lands directly on the flat side of the motor’s 8mm D-shaft. If a set screw hits the round part, the 70kg.cm of torque will eventually cause the shaft to spin inside your spacer, stripping it out.
Support Bearing: Because that iron weight is heavy, the motor shouldn’t bear the full weight of it. If possible, try to have the wringer’s own frame support the weight, using the motor only to “push” it around.
Take your breather! When you find that box of parts, check if the spacer you made has an opening that can be adapted to an 8mm bore.
Should I look up a 12V speed controller with a reverse switch for you? It’ll let you slow down the motor even further if the weight starts to “walk” the wringer across the tub.
I mean I put the weight on to make it easerier for ME – get it going and it i keeps going but if the motor doesn’t like it – not a big deal to tkae it off.
That weight was a brilliant “human-power hack”—it uses rotational inertia to keep the rollers spinning once you get them moving, which is exactly how traditional industrial machinery used to work.
Motor needs no help
However, since you’re switching to a Bringsmart 12V 12RPM motor, your “working relationship” with the wringer is about to change:
The Motor vs. The Weight
The Motor is the Boss: With 70kg.cm of torque, this motor doesn’t need “help” from a flywheel to keep moving. It provides constant, relentless force from the moment you flip the switch.
Worm Gear Braking: Because this is a self-locking worm gear, the motor’s internal gears physically cannot be spun by the weight. If the power cuts out or you stop the motor, that heavy iron weight will try to keep spinning, but the motor will act like a brick wall. This can actually snap the motor’s internal gears or bend the 8mm shaft.
Vibration and Wear: If the weight isn’t a perfect circle or is slightly off-center (imperfect concentricity), it will create “wobble”. At low manual speeds, you can feel this and adjust; but the motor will just fight it, which leads to heat and early motor failure.
Remove Weight
Once you find your parts, try the motor without the extra weight first.
Why: You will likely find that the 70kg.cm motor handles the wet laundry even better than you and the weight did together. It won’t “bog down” like a human does, so you don’t need the momentum to carry it through the tough spots.
The Handle: Keep the handle! It’s useful as a manual backup, and since it’s much lighter than the iron weight, it won’t put nearly as much stress on the motor’s gearbox during a sudden stop.
Pro-Tip for “Finding” Your Gear
If you can’t find that custom spacer, don’t sweat it. You can buy a standard 8mm-to-Xmm shaft coupler (where X is your wringer’s shaft size) for a few dollars. These often have their own set screws, saving you the trouble of drilling and threading a new one from scratch.
Should I look for a coupler that matches a specific shaft size for you (like 1/2″ or 5/8″)?