Mounting CB radio overhead, How long can the screws be?

[Cadillac Kid]

Hello everyone.

Alright, it's not actually a CB radio but a 2 meter radio or "ham" radio. Sorry.

I have decided the best place to mount it is in the center of the headliner at the very front. I'm going to use some screws or self tappers to mount the bracket, but I don't want to accidentally drill holes through my outer roof.
How long can the screws be? I know these trucks have two layers of metal in the roof and I only want to go through one. The size of the radio is equivalent to a CB radio, it just weighs a little bit more.
For all of you hardcore CB radio fans, I grew up on them. I still use them today and I have one in my other car.

Any help is appreciated. Thank you!

[abig84]

I mounted my dash cam mount up front all I did was carefully drill through the first layer of metal then just pushed the drill bit through til it touched the outer roof and marked the drill bit and found screws that were appropriate length and installed them with a hand screwdriver
I did it like 4 years ago so don't really remember the length of them.
I just figured it's best not to go ramming self tappers in there

[TKCR]

Do you have sun visors? Or headliner trim? Take one of those screws out, to determine the length. As long as you stay at that length or shorter, you should fine.

[SilverMiner]

Originally Posted by Cadillac Kid

Hello everyone.

Alright, it's not actually a CB radio but a 2 meter radio or "ham" radio. Sorry.

I have decided the best place to mount it is in the center of the headliner at the very front. I'm going to use some screws or self tappers to mount the bracket, but I don't want to accidentally drill holes through my outer roof.
How long can the screws be? I know these trucks have two layers of metal in the roof and I only want to go through one. The size of the radio is equivalent to a CB radio, it just weighs a little bit more.
For all of you hardcore CB radio fans, I grew up on them. I still use them today and I have one in my other car.

Any help is appreciated. Thank you!

Cadillac - I just went through this with my rig and a CB radio. The previous owner had hung the CB between the visors, running self tapping screws through the headliner and into the intermediate shelf-like metal running right above the windshield. I removed the headliner to refurbish it and after re-installing the radio with the same screws it fell down rather catastrophically while driving on gravel roads. I don't know how long it lasted for the PO, but I can't really recommend attaching something as heavy as a radio with only sheet metal screws.

To fix the problem, I changed over to rubber well-nuts and spread the load over four holes rather than two. So far, so good. I have attached a photo of what it looks like before the headliner is reinstalled.