I want to secure a "power rack" for weighlifting — a square cage that supports a barbell so you don't need a spotter for squat and bench press. I'd like to fasten it to a wooden platform. My first thought was to bolt it to the platform, but the rack comes with no pre-drilled holes.
The frame is 2" x 2" 16-gauge steel and looks like this: 
I haven't built the platform so I have some flexibility. Current plans: an 8' by 8' platform made of two layers of 5/8" OSB. That platform would rest directly on an old beat up concrete slab in my garage.
How would you connect/tie/bolt/whatever the frame to the floor?
Best Answer
This equipment has several bolts located near the floor I would put an angle bracket under the head of the bolt and fit a coach bolt from underneath up through the bracket and attach with a washer and a shake-resistant nut.
You cut a recess for the bolt-head by drilling part way through the bottom sheet with a spade bit.
Else tee-nuts for wood are a good option too, come downwards with a length of all-thread, glue it to stop it from shaking loose and then tighten down with a nut.