Will this work on my uneven shop floor?

Casters roll smoothly on level concrete and asphalt. Rough or heavily cracked surfaces may catch — inspect your work area first. Rolling on a thin mat helps on rougher ground.

How much weight does it support?

Weight capacity is not specified in the product data. Test it with your body weight before relying on it for extended underbody work — if it feels stable, you're good.

Do the casters lock?

Locking mechanism is not confirmed. You'll want to test whether casters hold position on an incline or if you need wheel chocks to prevent rolling during stationary work.