Roof structure question

[N8N_99xj]

how much room is there between the support at the windshield header (not right at it, but the "crossmember" about 5-6" back from the windshield) and the actual roof skin?

Reason I ask is I made what I thought was a cute little CB radio bracket out of 1/8" thick aluminum that goes under the visor clips as I've seen before; however it doesn't work with my Cobra 29 - too close to the windshield. I seem to be completely unable to find any aluminum or even steel stock wider than 2" (what I used for my 1st pass bracket) and I really need 3" or better yet 4". I'm sick of half the trim being perpetually off my interior and projects unfinished, and am *this* close to saying "screw it" (literally) and just running some Teks through the stock Cobra bracket and into the metal of the roof, as my headliner is far from perfect to begin with. However, what I don't want to happen is to do that and then see four little holes in the roof skin.

Could someone with a stripped out headliner please let me know?

thanks!

 

[xjtrailrider]

Here is what it looks like on a Comanche, its almost the same on the XJ

 

[N8N_99xj]

right, but I guess the real question is, can I shoot a 3/4" screw through there without forking up my roof? Or should I just wait until I have a chance to roll by the fab shop on a weekday and see if they'll sell me a cutoff scrap for cheap?

 

[xjtrailrider]

right, but I guess the real question is, can I shoot a 3/4" screw through there without forking up my roof? Or should I just wait until I have a chance to roll by the fab shop on a weekday and see if they'll sell me a cutoff scrap for cheap?

Can't you go with a shorter screw?

My CB is mounted there on my trail rig

 

[N8N_99xj]

That's what I have :/ have to go to store to get anything shorter. And Home Despot on a Sunday will make me homicidal, the customers are almost as bad as Walmart.

 

[O-Gauge Steamer]

In sheet metal, the screw only needs to be long enough to grab the sheet. Anything longer is just for fun...

As a side note, in steel, one diameter of thread is sufficient to hold torque for the fastener. In aluminium, use two diameters.

Which explains why the thickness of a nut always matches the diameter of the bolt it fits.

In case you were wondering.

If not, never mind...

 

[rockclimber]

Pre-drill the holes slightly smaller than the screw. Slide a small punch or even a paper clip in the hole until it bottoms out on the roof. Mark it, Cut the screws shorter than that By 1/16" of an inch or so (including the 1/8" for your bracket)

 

[N8N_99xj]

OK, I'll hold off until tomorrow, if I can't get any 4" wide scrap aluminum from the local fab shop I'll get some shorter (and fatter, I think the biggest I have are #10 anyway) sheet metal screws.