Bolts needed for Bolt on slider

Im planning to have a bolt on slider attached to my taco but kinda clueless on the bolt measurements to use with the stock threads on the frame. I have it fabricated but the fabricator doesnt know the required bolts needed. Any suggestions for those who had theirs bolted? Would appreciate it thanks!

 

I would think any fabricator worth their salt would be able to figure out hardware. Tough to say if it's custom, as not all of them use the same holes for mounting. They also don't thread into the frame itself, the holes aren't threaded, so it's usually a bolt with a big washer or backing plate, then a nut.

You could look at some install instructions to get an idea of what size/grade bolts are used for some of the big names. Here's RCI's instructions for their sliders:
https://rcimetalworks.com/wp-conten...OTA-TACOMA-ROCK-SLIDER-INSTALLATION-GUIDE.pdf