Any Ideas on how to mount lights onto the roof rack?

[festiboi]

Hey guys,
I’m going to mount some driving lights on the front crossbar of my 92 Explorer’s roof rack. However, I’m not sure how to mount them without drilling holes, which I refuse to do. I don't have the heart!

Any suggestions or ideas of anything that can grip onto the roof rack without causing any damage and has a slot for the light’s base to slip into and tighten with a bolt?

I’m going to visit Home Depot later today with one of the lights and the actual crossbar to see what they say

 

[natenkiki2004]

Without drilling holes? Bite the bullet and drill holes in the vertical support pieces. Putting them up on top will be far too wobbly, I've done it. I made L brackets to mount them on the edge. I need to refine it more but they're a lot more stable this way and I can still put stuff up on the roof.

https://dl.dropboxusercontent.com/u/464376/vehicles/1991 Explorer/Pictures/IMG_20150223_165706.jpg