After seeing the prices on real lawnmower blade balancers ($100+ US), I decided to design my own. It works by mounting the base on a wall and magnetically attaching a blade. The heavier side will rotate down. Use a grinder to remove some metal from the heavy side until it remains in a horizontal position when attached to the balancer. It can also be used to verify the blade isn't warped by using a tape measure at the tip of the blade and then spinning it 180 degrees to check the other tip.

To make this, you will need:

• Super glue to adhere the magnets to the chuck
• Four 60x10x5mm rare earth magnets (https://www.amazon.com/gp/product/B07QWMHGHZ)
• Two 608 ball bearings (https://www.mcmaster.com/5972K222/)
• One 8x40mm shoulder screw (https://www.mcmaster.com/92981A206/)
• One M6 lock nut and one optional 6mm washer

The shoulder screw and ball bearings will likely need to come from McMaster, but Home Depot carries two packs of the M6 lock nuts. Also, I used sealed bearings but they don't have to be.

No supports are needed to print. It is designed for .333mm thick layers and .5mm width on a .4mm nozzle. The hub and inside of the chuck will need to be sanded until the hub can smoothly slide into the hub. It needs to slide as this is how the balancer attaches to different size blades. I used ABS with a quick acetone vapor bath after sanding.

If you decide to remix this, please use the license I have selected as I don't want to see these online for sale without recourse.