I don't need no stinky digital camera. I am an artist laugh

Make 2 two L looking piece (see picture below). Connect them together both on top and bottom. On bottom connect with the wide part of the wood resting on the ground for stability. On top connect with edge of the wood facing up so you can hang The motor. The motor hangs inside the 2 L. Since you are a carpenter you know how to make a strong L and how to connect them good.

Ignore the dots (..) in the picture I had to put them in there to fill up the blanks. Does it make sense?

for 300 lbs you need to beef it up. Mine holds fine for 100ish. The long piece on the ground (leg of the L) prevents motor from flipping over.
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I'm a great believer in luck, and I find the harder I work, the more I have of it. Thomas Jefferson.