I am trying to find out when Ford started using 13/32" studs for the driveshaft housing/roller bearing spool. I have a torque tube that will accept 3/8" studs at the bottom flange, but not 13/32". The recesses for the bolts on the front and rear castings of the driveshaft are also different than is usually seen. I also see the tube in not machined where it enters the front casting. I am trying to date this torque tube. It is not the very early long type. The ball and ring are later so that's no help. Any information is appreciated.
The larger rear end studs made it necessary to also have larger holes in the pinion spool to allow the larger studs to pass through it. That change resulted in the pinion spool housing being given the suffix "B". This drawing with the new larger holes was adopted on 4/22/10 so that would be then the same time that the stud was changed and the holes in the drive shaft lower flange being bigger too. Most likely within days of each other the drawings would all have to have been changed. Incidentally these first "191B" pinion housings (spools we now call them) were simply redrilled earlier round housings with a letter B added to the factory number. In fact I have found many of the "A" version (marked simply 191) that have been drilled out to accept the larger stud. I have also found both A and B version of 191 round spools that have castings so thin in the bolt area that you can see into the things and see the studs. There wasn't enough metal in the early pattern to support them simply being enlarged by drilling to a larger bolt size. Thus the spool pattern was changed and "bumps" appeared at each stud pocket to put more metal on the pinion spool so that drilling out the stud pocket holes would not bore through the sides of the metal casting. This was the reason that the later spools have "bumps" on them. Unfortunately the exact date of the bumps being added is unclear since that change was only "documented" on 12/27/13 with notations saying the drawings was being updated to agree with the parts as they were currently being made. Thus the bumps began sometime before that. I have seen both ROUND and BUMP type spools marked 191B. The iron was changed from malleable iron to cast iron on 2/20/13 so it is possible that the pattern was changed at that time too. No way to know for sure since Ford didn't catch the lack of documentation error until 12/27/13 (probably just after the Christmas partying was over ha ha). We have only the fossil record to go by for that one. Have to look at some original 1913 cars to get that answer.
Thanks John, if you run across a 191 with the 3/8" holes you would sell, let me know. I'll probably see you at Chickasha. Thanks for the info.