[rob love]

So one of the questions, as mentioned earlier, is if a 15cwt frame can be used for an artillery tractor. And if so, why are the part numbers for the side rails specific for the FAT? I think I have the answers now.

Yes, the 15cwt frame is pretty close. All the holes are already on the 15cwt frame for installation of the winch, the overload springs, and the installation and relocation of the various crossmembers. Except... the rear hitch and rollers. The last foot or so of the frame has completely different holes for the hitch that is at frame level, and the large plate that holds the sheaves and roller. There is also a long bar on mine that goes forward of the crossmember and bolts to the underside of the frame. Aside from those, the frame seems identical.



I think I may have found another anomaly in the brackets for the winch. I have a gap at the top of the brackets, in which I may have to make up a shim to space it out. The old frame in that area was so beat up I can't be sure what the height was, but I will measure one at work to compare.I noticed that the one at work has these plates welded to the frame at the top and bottom....they did not depend on the 8 smallish rivets to hold the winch in place under load.


There were too many holes on the back horns of the 15cwt frame to allow merely redrilling to fit the FAT hitch and rollers, and as the back part of the FAT frame was not that bad, I decided to graft it onto the new frame. I did note that it seemed the FAT frame was about a 1/4" longer, although that is likely not critical. I made my cut and weld at an angle to give more welding area and ground them reasonably flush. The winch will likely never be used, and certainly not heavily, so I am pretty sure it will be OK. I had considered boxing the inside of the frame in the area that the weld is, but I think that may be overkill. Time will tell.



The plan now is to remove the rear brackets again, sandblast and paint the frame, then start installing the various brackets and crossmembers. Before that I need to re-enforce the bracket that holds up the cowl on the frame. It was quite cracked, and I note that the later frames had a second layer of sheet metal spot-welded into them so it may have been a weak spot.


I spent yesterday moving the two piles of parts from the donor 15cwt and the FAT. It was getting to be a nuisance driving around them, and winter is just 3 months away. My hope is to have a rolling chassis by then, and I have no expectation of having the cab ready to go back on. That will be for next spring.


Attached are some photos of the graft.