Farmall Cub

I am still inclined to believe that the shifter fork is original. I can't prove this of course. I am a retired industrial/manufacturing engineer. While I am not a machinist or tool and die maker, I am familiar with metalworking and sheet metal fabrication processes. I am not trying to "beat my chest", just telling you about what I have seen in a career of 40+ years.

Anyway, the top half of the fork (machined) acts as a clamp to secure the shifter fork to the rod. The bottom portion (stamped) has a nut welded to the bottom to receive the bolt that comes from the top. This nut looks to have been resistant welded as the other fixed nuts on other parts of tractor. I don't think it was welded in "Bad Bubba's Welding Shop".

The other point is "Uncle Bob" has spent his whole life in the same area of rural Middle Tennessee. This part of the country was not noted for any machine shops that would have the capability of machining the top clamp.

I am not trying to belabor the point. But, I just think that this part could be some history of engineering changes that were made.

The nut welded onto the bottom side of the fork is original. Whoever made the top clamp simply drilled the hole to line up the same as the original bolt. If you closely examine the stamped part of your fork, you will most likely find the edge where it starts to wrap around the rod is a broken edge, possibly clened up with a grinder or file. That part of the edge is unlikely to match the finish along the rest of the edge.

Before it broke, the sheet metal wrapped most of the rest of the way around the rod to provide a hole for the bolt. It was much like what your 2-3 fork looks like. If the original fork was built with a separate clamp, you would be able to find a part number for it in a Parts Catalog. Even the June 1947 edition of the Catalog has a drawing of the fork that looks just like the one in the final edition.

Jim Becker, the TC-37 Catalog has p/n 3530444R1 Shifter Fork Clamp used with Forks 355600R93 and 355601R92 for s/ns 8525-13586. Could this be what is on my s/n 9216 Cub? I wonder if this could have been a "work-around" until the tooling could be available for the correct shifter fork?

How about that. I've been looking at the listings for the forks and never noticed the note for the clamp. My 12/47 revision of the Parts Catalog doesn't show it and 12/47 was during the time they were building the ones with the clamp.

I now see that TC-37A (5/49) actually lists 4 variations of the R-1 fork (although the 4th version was the universal replacement). The note calls for use of that clamp for both forks. Yours only has it on the R-1 fork. I wonder if they really used it on both forks. Maybe your 2-3 fork has been previously replaced. Four different versions of the fork in that much time suggests they were having problems from the field and were trying to come up with a stronger fork. I know they made more changes later, so even 4 tries didn't get it.

I can understand them having problems with the forks. That is a challenge for a tool designer and tool maker to punch press and form a part of this configuration. In order for the clamp portion to be effective, the ID probably has a fairly close tolerance. Also, to be cost effective, the part is probably made from mild steel with no heat treating. Sometimes, several versions are made before finding one that will hold up.

How about posting some photos of this part? Would be interesting to see.

OK, I just got back from my shop in sub-freezing weather to make some pics. I know, I know that's not cold to my friends up North. But, it sure feels cold in Tennessee.

Anyway, here are 3 shots of the clamp. Now if some of you computer wizards would go out there and post the clamp pics on here, it would help everyone see it better.


http://s222.photobucket.com/albums/dd21 ... all%20Cub/

BIGHOSS wrote:OK, I just got back from my shop in sub-freezing weather to make some pics. I know, I know that's not cold to my friends up North. But, it sure feels cold in Tennessee.

Anyway, here are 3 shots of the clamp. Now if some of you computer wizards would go out there and post the clamp pics on here, it would help everyone see it better.


http://s222.photobucket.com/albums/dd21 ... all%20Cub/

I'm not a wizzard, but with the benefit of hindsight it's easy to see why this design failed. If it were my transmission I would still replace that experimental (failed design) fork.

Here's the rest of the photos. Sorry for the size, but that's how they were in PhotoBucket.