In Reply to: Original look posted by BW on January 12, 2021 at 16:36:17:
Yes, as Steve mentioned, and I forgot to emphasize, is that most fasteners today are not designed like the original Ford ones were as far as bolt length, hex head size, and nut and washer thickness. FORD designed bolts with lengths being in fractional sizes -it's the way they made them back then. Both Henrys came from farms and insisted that a bolt length would not protrude more than 2 threads beyond the fastened nut. The reason was so that the farmer wouldn't catch his clothing on one and rip his pants or shirt. Hence many bolts and studs were made in odd lengths that are no longer industry standards. For example, a 2.12" bolt length is not made anymore. You get 2.5" (may find a 2-1/4")and that's it. Hex heads AF (Across Flats)nuts bolts used large sizes for example, a 5/8-18 hex nut and bolt used a 1-1/16" AF size. Now they are 15/16 or 1.0". One reason for this is that the FORD 9N-17014 Plow Wrench, originally a Ferguson design and concept, was intended for the two main sizes used on the plow and tractor - 11/16" and 1-1/16". Nuts and washers were also made extra thick. I have my own additional/alternate theory. Material costs. It may seem trivial but if you do the math it makes sense. Using the standard size of 1/2-20" for thread pitch, calculate the material used to make a 1.0" length. Nominal thread size is 20 TPI (Threads Per Inch) which is also the 'pitch' of the thread. Take 1.0" and divide it by 20 to get the pitch dimension -the distance from one thread to the next. Thus, 1 ÷ 20 = .05" . Every two threads equals .100". Multiply .100 by 10 to get 1.0". Every inch or fraction thereof of material would add up in costs. It may seem trivial as I said but when you consider making tens of thousands or millions of nuts and bolts, that 1 inch of steel used to make that bolt adds up in dollars and cents. New bolt lengths can be frustrating to work with too. Some bolts are not threaded completely the full length of the bolt. That may leave it short and not be able to fully fasten down. A 2.12” bolt length would need now use a 2.5” bolt. To be authentically original, you would need to grind or rubber wheel it down 3/8”. If the new bolt is a shoulder bolt, not completely threaded, it may fall short when fully fastened down. Using a thread die to make it as such can ruin the die because the bolt is probably hardened and it will ruin the die. Hex heads also most likely made smaller to reduce material and costs. Some can be found new like the original 7/16-20” Hex Nuts used 11/16” AF and can still be bought as such. However, a 7/26-20” Bolt will only have a 5/8” AF Hex Head now. Dennis Carpenter makes several of the OEM fasteners and sizes, especially the fine thread carriage bolts. That is why I highly recommend when doing a restoration on a tractor or implement you try to keep and reuse as many original fasteners as possible.