The Stovebolt Site Forums The Shop Area Making a Stovebolt Bed 1947 Chevy cross sills question

I am finally getting around to working on my bed. '47 Chevy 3600. I have had the cross sills for quite awhile, originally from Mar K. The pictures I attached show what I have for sill labeled #2 which I believe is the last one back from the cab. It looks nothing like what is shown in the instructions that were included. Am I looking at something wrong or do I have the incorrect cross sill?

The only difference between the second cross-sill on my truck (also from Mar-K) is the "bedside brackets" on the end. Mine is just straight with no brackets and is the one that floats above the frame just in front of the frame hump. The only one that has anything additional near the ends is the rear cross-sill. I think you could use it, but the brackets could be removed. I don't see how thy could attach to the bedsides, but I could be wrong. The third cross sill has bolts thru the wood and frame. The front cross sill has holes along the front edge to bolt to the front panel of the bed. Here's a picture of the 4 cross-sills when I first primered them after getting them home from Mar-K. And another with the front and rear cross sills bolted to the bed sides. You can see the extra bracket on the end of the rear sill in that photo.

Thanks for the information. None of my cross sills have holes along the front to mount the bed front panel. And I don't have a cross sill like your photo for the one nearest the tailgate. I can't see how mine would attach to to bedside.
Is there a difference in years or models? All 47-53 3600 the same cross sill setup?
I appreciate your input.
Chuck

The only difference between mine and the earlier trucks would be in I believe the #2 cross sill would be a relief area on the bottom right side to clear the underbed gas tank that the 47-48 trucks had. Otherwise, I believe that they're the same from 47-53.
Post some pics of yours showing the whole cross sills and maybe someone can help you figure out the puzzle.

Here are a couple of shots of what I have mocked up.My first cross sill does have the holes to mount the bed front. None have the relief area for the under bed gas tank,which is fine, I won't be using one. I think my only issue is with the cross sill labeled number 2 in the pictures.

The sills are 49 7/8 long.The dimensional lumber is a reference stick, not part of the bed assembly.

Yeah that #2 with the brackets is funky. The rear cross-sill has to be longer than the rest to fit into the stake pockets at the rear. It also gets a vertical weld bead to the stake pocket. Here's another pic of my bed assembly (zoom in on the lower right corner where the line-up punch is sticking thru holes in the stake pocket and cross-sill.) I think you're going to have to get another rear cross-sill. Contact Mack Products They have absorbed Mar-K's products, and should be able to supply with the rear cross-sill that you need.
I'm not seeing the holes for the front panel, but maybe you have that cross-sill turned around in the pictures. The sill goes behind the front panel.

My 47 3600 cross sills had nothing like that. I purchased them from LMC trucks. I would make sure I have the proper rear cross sill, like was mentioned, then remove those brackets.

Ya'll answered my questions and confirmed what I thought. I will heed your advice and continue.

Thanks,

I have a '50 3600 with bed sills from Mar-K.

The second cross sill is the second one from the cab and the end brackets bolt to the bed sides in addition to the angle brackets attached to the bed sides.

I don't have a decent picture of the cross sill installed but my assembly directions from Mar-K I have marked up step 15 - "second and third cross sills ... 26-3/8" and 44-1/4 (was 35-3/16) from the front bed panel....The fourth and fifth cross sills ...63" and 74-1/4" from the front panel (not the 53-1/2" in the instructions)."

With the 3100 at least on my '51, nothing bolts to the bed sides except the rear cross sill. The second cross sill bolts only to the wood and the angle strips, and floats above the frame. I could see where the second cross sill with the brackets on the end could bolt thru the bed sides. Maybe that was a 3600 feature only.

Kevin, does your bed have a stake pocket about 18" behind the front one? I beleive the cross sill bolts go just in front of the second stake pocket and inside the second stake pocket on my 3600.

No, the 3100 beds just have 2 stake pockets on a side.

It kind of makes sense that the longer 3/4 ton beds would have some extra bed wood support between the #3 cross sill that sits on the frame and the #2 that floats above the frame (at least it does on my truck.)

If you could post a picture of how that cross-sill bolts on to the bedside, that would help chuck2213 figure out how to deal with that.

The attached is the best shot I could get. There is another vertical bolt that goes through the channel that is not visible, there are two bolts that go through the cross sill end bracket and the bed side angle bracket, these two bolts are closer together than the other angle bracket to cross sill bolts.

The rear horizontal bolt goes inside the stake pocket whereas the front horizontal bolt head is exposed on the outside of the bed.

I was wrong earlier about this being the second cross sill back from the front, it is the third (if you count the front one). This cross sill also has bed mounting bolts that go into the frame. There is one floating cross sill between the front cross sill that the bed front bolts to and this one.

Great update! I am still in the mock up for the bed until I am confident in my setup. I placed the cs labeled #2 with the brackets 26 3/8 back from cs #1.The bedside does have existing holes that line up with cs 2. The 44 1/4 measurements placed #3 right over the frame hump/axle.
Thanks again for your help!