cross sill fabrication

[rick0312]

any of you guys ever fab up cross sills for our trucks? I was thinkin about using square tube, but wanted to see what you thought.

[litew8]

don't see why it wouldn't work

[passthebuck]

I did & it worked great. You'll need lots of 3" x 2", a bit of 1" by 2" & I put 3 pieces together to make the 3/4" cross member. These measurements are for steel beds. If I could do it again, I would have notched one of the cross members for an under bed fuel tank.

http://67-72chevytrucks.com/vboard/s...d.php?t=138385

[MikeyMan]

I just did that to my truck. The steel bed floor and some of the c-channel cross supports were rotted out. This will be a daily driver, not a resto, so looks weren't important. I just want to use the bed without me or the contents falling through.

I had a bunch of aluminum square tube, 2" x 1.5", that I scrapped and saved from a demo job. Two pieces stacked together made a perfect 3 inches from the frame rails to the bed bottom. Bolted to the frame, and pop riveted to the solid parts of the bed floor.
The double stacked tubing is very strong, yet lightweight and easy to work with. I did that in two locations.
The area above the axle, my c-channel support was rotted and sagging there too. At that location the frame goes up closer to the bed bottom. For that spot I used the shallow (approx. 7/8") uni-strut. It fit the gap nicely, used a piece to the front and the rear. Through bolted the uni-strut to the frame with the "c" or open end down and the flat slotted side up against the bed bottom for support. I can add spring nuts and threaded rod for pipe hangers. (idea borrowed from electricians/plumbers)

The square tube and uni-strut worked great to reinforce and strengthen the bed supports. I used two pieces of steel plate to then cover the whole bed floor. Fastened with silicone and pop rivets. Worked great, looks good.

[crazy longhorn]

Yup, I did a tread plate steel floor in my longhorn. The rear sill was a 3x3, center over the axle was a 2x1, a 2x2 for & aft at the wheel tubs, & the rest were 2x3. With a sheet of 14 guage buttoned welded to the sills, it makes a very stiff floor(the truck goes straight,while pounding gears) crazyL

[rick0312]

thanks! i am converting a steel long bed to a wood floor so I believe the sills are 2" instead of 3". so I guess a 2x2 square tube would do the job. If anyone has measurements for wood bed sills that would be a great help...thanks

p.s. thanks for the link passthebuck.......great work you got some skills!

[MarvsBoy]

Nice thread. I was just thinking of doing this to a "driver". Glad to see I wouldn't be doing something that's never been done before.

[noxqsz]

You guys are an inspiration to old Chevy truck guys everywhere! This site is the most valuable - and enjoyable - source of information and inspiration anywhere.