Shortening a pickup frame

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  • winchman
    Senior Member
    • Aug 2003
    • 4030

    Shortening a pickup frame

    A friend brought in the frame from a long-wheelbase '68 Chevrolet truck for me to convert to a short-wheelbase. Fortunately, he brought along the instructions and two frame inserts to make the job easier.

    Removing 8" from the rear was pretty simple after I spent the morning getting the overload spring mounts removed. There was some serious rust on the bolts to deal with.



    I marked and cut diagonally through the frame under the cab to remove 12". Then I put in the inserts, and welded it up. There was a lot of checking to make sure everything was still square.





    Then I removed the two rear cab supports, and moved them back 12".

    Any products mentioned in my posts have been endorsed by their manufacturer.
  • Old Hat
    Senior Member
    • Mar 2014
    • 1916

    #2
    Damn Cool to see a job like this done so WELL !
    I miss have-ing an Iron worker on hand . . . looks like a Scotchman back there.

    My fororite way back was the Hill Acme.

    Comment

    • CarlByrns
      Senior Member
      • Oct 2013
      • 2001

      #3
      That's some nice work! What did you cut the frame with?

      Comment

      • Kevin B.
        Member
        • Apr 2006
        • 46

        #4
        Impressive welding, wish you lived nearby.!

        Kevin B.

        Comment

        • A.K. Boomer
          Senior Member
          • May 2006
          • 20865

          #5
          Yes very high quality work WM, good job on matching up the diagonal, that suckers built to last...

          Comment

          • winchman
            Senior Member
            • Aug 2003
            • 4030

            #6
            We have two Scotchman ironworkers. That's the smaller one.

            I used a die grinder with a thin cut-off disc to make the cuts. It's a little more accurate that the plasma or OA torches, and the cut line is still visible when you're done.

            I was impressed with the frame braces he bought for the project. They fit perfectly, and made the project much easier.
            Any products mentioned in my posts have been endorsed by their manufacturer.

            Comment

            • Doozer
              Junior Member
              • Jan 2005
              • 10595

              #7
              Why would you ruin a long wheelbase truck and make it a short bed?
              I like to haul stuff in a truck, and you can fit more in a long bed.
              Why limit yourself on purpose?
              I would look for a long bed box instead.
              But it is a free country, and as an engineer my logical thinking
              most always seems to annoy most people, so no ill intentions
              intended.
              Nice splice by the way. My did used to have a 120 ton Scotchman.
              It was a nice machine, but it came with metric threaded holes in
              the bolster. It made it such a pain in the azz to stock all those
              18mm bolts for setup tooling. Lousy metric. I would think buying
              a made in USA machine, it would have 3/4-10 threads, or something.
              Another minor annoyance, when we operated it at -20F, the hydraulic
              oil was so thick, the stop valve would ever run the travel, and break
              the limit switches off the mountings. A 200w light bulb under the
              hydraulic tank fixed that. At that temp, we used to 80% immerse
              a 200w light bulb in the coolant water of the Doall cutoff saw.
              The bulb under water kept the coolant from freezing. Should have
              had a GFI outlet for protection, but they were new back then.
              -Doozer
              Last edited by Doozer; 07-18-2014, 09:39 AM.
              DZER

              Comment

              • Bluechips
                Senior Member
                • Jul 2012
                • 175

                #8
                Originally posted by Doozer View Post
                Why would you ruin a long wheelbase truck and make it a short bed?
                I like to haul stuff in a truck, and you can fit more in a long bed.
                Why limit yourself on purpose?
                I can't speak for WM, but most folks I know don't redo a vintage truck (68) for it's utility. It's usually for a hotrod or show truck. Most people prefer the short beds for that. The long beds are more plentiful and usually cheaper, so shortening one is common practice. The step beds are available reproduction for most makes.

                Comment

                • vpt
                  Senior Member
                  • Dec 2009
                  • 8808

                  #9
                  No bolts in the plate?

                  There are people that would say that is still done wrong, they might mention something about the welds at the end of the plate going vertical creating a stress riser and the frame might crack there. They might also say that the angled weld should have done first, ground flat, then plated. Some would mention too that the plate should be fish mouthed at the ends as to not have stress risers.

                  I am sure those people will be along at some point, brace yourself.
                  Andy

                  Comment

                  • Old Hat
                    Senior Member
                    • Mar 2014
                    • 1916

                    #10
                    Originally posted by vpt View Post
                    No bolts in the plate?

                    There are people that would say that is still done wrong, they might mention something about the welds
                    I am sure those people will be along at some point, brace yourself.
                    Detractors are like flies . . . around a fresh cut pertectly ripened Water Mellon.

                    Comment

                    • Old Hat
                      Senior Member
                      • Mar 2014
                      • 1916

                      #11
                      vpt (Andy);

                      In about 1976 on a foggy friday night I and my buddy got off the path somewhere in Stevens Point, WI.
                      I was driving slightly downhill, and the headlights suddenly looked very strange.
                      I hit the binders enough to spill my coffee.

                      I got out and found we were about to drive into the drink.
                      I was appearently going down a boat launching lane. (:~O
                      Last edited by Old Hat; 07-18-2014, 01:23 PM.

                      Comment

                      • Willy
                        Senior Member
                        • Oct 2005
                        • 8987

                        #12
                        Originally posted by vpt View Post
                        No bolts in the plate?

                        There are people that would say that is still done wrong, they might mention something about the welds at the end of the plate going vertical creating a stress riser and the frame might crack there. They might also say that the angled weld should have done first, ground flat, then plated. Some would mention too that the plate should be fish mouthed at the ends as to not have stress risers.

                        I am sure those people will be along at some point, brace yourself.
                        You're absolutely right Andy, in a highly stressed section of heat treated T-1 commercial truck frame those are the accepted frame repair procedures.
                        Winchman though has done some very careful planing and a very professional execution of the frame modifications. The section under the cab and in between the two cross members is arguably the least stressed section of the frame. A properly prepared diagonal butt weld would probably have sufficed.

                        The frame modification as done by Winchman has been seriously thought out and in my estimation at least is now very likely the strongest section of the frame.
                        Well done Winchman!
                        Home, down in the valley behind the Red Angus
                        Bad Decisions Make Good Stories​

                        Location: British Columbia

                        Comment

                        • Dieseldoctor
                          Member
                          • Aug 2011
                          • 54

                          #13
                          Just curious. Did you take steps to correct the Ackerman angle or is he going to take care of that?

                          Comment

                          • flylo
                            Senior Member
                            • Apr 2011
                            • 8848

                            #14
                            Sure it was coffee?

                            Originally posted by Old Hat View Post
                            vpt (Andy);

                            In about 1976 on a foggy friday night I and my buddy got off the path somewhere in Stevens Point, WI.
                            I was driving slightly downhill, and the headlights suddenly looked very strange.
                            I hit the binders enough to spill my coffee.

                            I got out and found we were about to drive into the drink.
                            I was appearently going down a boat launching lane. (:~O

                            Comment

                            • Joe Rogers
                              Senior Member
                              • Mar 2011
                              • 357

                              #15
                              Originally posted by Dieseldoctor View Post
                              Just curious. Did you take steps to correct the Ackerman angle or is he going to take care of that?
                              Since the splice was behind the front suspension under the cab the geometry should not have changed from the design specs. The caster on these alignments is adjusted after the frame angle is determined and is compensated for with a plus or minus calculation. This is a very limited mod as far as a street truck. It is far from some of the junk I see now and then. I wouldn't ride in some of the junk out there...
                              Joe

                              Comment

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