How did you mount traction board to roof rack

Considering mounting XBULL traction boards to roof rack by UpTop. How did you guys do it? What hardware is needed? And I will be wanting to make it padlockable as well.

Thanks all in advance

 

I dont have the uptop brand, but the rails look the same at mine. I used some slot nuts that fit inside the slat.

8020, 3675, 10 Series Stainless Steel SS 1/4-20 Centered Slide in Economy T Nuts Hardware Nuts for 10 Series Aluminum Extrusions (15)

https://smile.amazon.com/dp/B00QKOL...olid=1PVCHI180IPO9&psc=1&ref_=lv_ov_lig_dp_it

and some 1/4 all thread cut to the size i wanted. And something similar to these to hold them in place.

DCT 5 Star Knobs 5-Pack 1/4in-20 Internal Threaded Knob Clamping Knob Jig Knobs – T Knob Plastic Knobs, Threaded Knobs

https://smile.amazon.com/Knobs-5-Pa...1/4+plastic+handle&qid=1612930477&s=hi&sr=1-4