Getting ready to replace the cab corners on my 56 F100 and need some help.
Im not sure of the proper method of measuring for the cut. I plan on using a butt weld to attach the new panel. Ive been told to allow 1/4" of metal on the cut line, then trim the rest to fit the replacment panel. I have been worried about getting this right and really want to learn the proper method. Any advice would be greatly appreciated.........

 

I just put cab corners on my '78 F-350. The way I did it was I bought a right and left side patch panels for my truck through LMC. First I made a horizotal upper cut 4" above the rusty panel and then drilled out my spot welds around the outer edge. Then with a cold chisle I carefully pryed the cab corners off. Then I used the peice that I cut off and traced it on the new panel. Always make the new panel longer than the trace line so you can fine tune it for the best fit. Then I sand blasted inside of the cab corners and sprayed weld-though primer on it before I welded the new patch panel in. When I got the new panel trimed and fitting the way I wanted, I slowly butt welded the top cut closed and drilled new hole around the outer edge and plug welded the outer edge where the factory spot welds used to be. Its not that hard to do. Rust repair and painting to me is funnest part of a project.

 

Thanks and hopefully i will agree with you on this being the funnest part after I'm done. What do you think about cutting the old panels out with a plasma cutter?

 

I wouldn't use a plasma cutter for cutting out cab corners just because I might warp the cab too much. Also, a lot of the older trucks have the fuel tank behind the seat.