Quote:
Originally Posted by Private_collector
I have reservations about loading forces on replaced sections, in eventuality that I do use to tow something. What do you think?
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Naturally it's preferable to avoid any joins in the chassis rails if possible, however if it's done properly I'm sure it can be just as strong, if not stronger, than original.
Sometimes it's unavoidable, for example one of my FGT chassis has been chopped just behind the rear crossmember, so I'll have to butt weld the chopped sections back on, and weld some reinforcement plates inside the rail. The replaced section has to carry the rear fairleads as well as the pintle hook, so the join will have to bear winch cable forces as well as towing forces. For cosmetic reasons I don't want to plate the outside of the chassis rail, but even without external plates I'm confident it can be made at least as strong as original. Naturally I'll keep an eye on it but even if it does fail I'm sure it won't suddenly fall off completely.
If you're worried about weakening the rear chassis by extending it, you may be encouraged to know it was standard RAAF practice on F60Ls. It so happens I have one of these. The chassis has been extended about 22" by inserting a section of channel inside the chassis rail, overlapping about 6", and welding "band aid" patches on the top, bottom, and outside. A second rear crossmember has been fabricated, and riveted in place about 22" aft of the original one. The pintle hook is mounted as usual, so they obviously had no concerns about towing. In fact I've been told the whole purpose of the exercise was to improve trailing when towing (although I suspect on mine it was also to accommodate a lengthened tray).
The Ford manual also recommends: "Whenever it is necessary to cut or remove any portion of the frame, the rail should be cut at an angle of 45 degrees, in other words, make the cut longer than the width of the rail." It also talks about reinforcement plates (page J-4).
Based on RAAF practice and the Ford manual I would conclude that it's quite acceptable to chop and rejoin the chassis, provided it's done properly.