FYI, this may help someone. I discovered the blade screws are M4 x 0.7mm. One of my screws had stripped out the threads in the aluminum hub, so I removed the blade motor from the chassis, then drilled out the holes and re-tapped them using an M5x0.8mm tap. I bought stainless steel M5x0.8mm x 12mm socket head screws and M5 washers at Lowes for about $4 total. They’re driven by a 4mm hex Allen wrench. I also had to drill out the blade’s holes to 7/32” to fit the slightly larger screws.
From now on, I’m only tightening the screws with a hand driver (and thread locker) instead of a ratchet wrench to reduce the chance of stripping the threads again.
