MATT - There was a really good article in Red Power Magazine on the WP plant a couple yrs ago. Besides nuts & bolts they made the magneto's, distributors, some carburetors, tiny pump gears for things like engine oil pumps. Really busy place back in the 50's & '60's.
I never got into the WP plant to actually see their production operation but have been thru other bolt mfg. plants. WP had some pretty good sized equipment. Later years when I was at FARMALL there were a lot of really BIG bolts holding those beasts together.
I find it interesting that you look at the hardware listed in the old parts books, say for a NF CC, the bolts are listed in increments of as small as 1/8th & 1/16th inch. Now days most hardware is only available in 1/4" increments in the small sizes then jumps to 1/2" increments, bigger sizes, say 3/4" dia & larger only in 1" increments.
Some hardware items IH bought from outside suppliers of course, only things that HAD to be IHC was engines, major castings, but most everything else was open to competitive bids. That explains why every 2WD FARMALL built after about mid to late-Nov. 1976 has a little "jd" cast into the frt axle casting. Farmall stopped buying them from the IH Memphis Foundry and got them locally from another foundry located in Silvis, IL. Saved a lot of money on freight!
ANYHOW, the rear rims were clamped onto those big FARMALL's with 3/4" dia by 4-5" hex-head Grd #5 capscrews. There were 24 or 32 per tractor just on the rear wheels alone. The bolts from WP were never really a problem but one day they got into a new batch of lock washers that were too hard, and they'd crack & break, then the pieces would fly out from under the hex nut. THAT really caused some problems, almost shut the finish line down one afternoon. No such thing anymore as an "unimportant part" in manufacturing.