Early 6 rivet rear end question

[RGould1910]

I'm making studs for early 6 rivet rear end housings. These housings accept studs with a thread size of 3/8 x 24 tpi. I've been told the other end of the studs are threaded 3/8 x 16 and and are held with castle nuts of that size and wired together like later set ups. However, I thought I recall seeing another early 6 rivet rear end that used 3/8 x 24 threads on both ends of the studs and were held in place with regular nuts not castle nuts and consequently were not wired.
Can someone please tell me which is correct?

[Jerry VanOoteghem]

What studs are you referring to? The 6 that attach the torque tube, or the 3 that hold the differential together?

[Scott Rosenthal]

Pretty sure that all clamshell housings use 6 fine thread castle nuts. Most 6 stud torque tubes have the nuts secured with a wire, but the no-rivet housings used individual cotter pins for some duration.

[RGould1910]

I am referring to the six studs that pass thru the spool into the
rear end housings.

[Scott_Conger]

I don't know the early early stuff well at all, so forgive me when I ask:

"are you sure those are the correct threads?"

and

"they were different than later 13/32-16 studs?"

thanks for any knowledgeable folks who may educate me

[Wayne Sheldon]

Scott C, Why Ford went to such an odd size for those six studs/bolts/nuts I do not know! Henry Ford himself was one of the founders of the SAE and standardization of hardware and some parts back around 1904 (ish?). That he would adopt that ridiculous in-between size makes no real sense.
I don't recall exactly when the change was made to those odd size studs and nuts, however basically, the first two years of model T Fords did have common standard 3/8 studs and nuts. They were not quite adequate for the stresses involved, and an increase in the size was warranted. Why he didn't simply go up to the next full size is what makes no sense to me? Yes, I know that in-between size was used on some other machinery at the time. But even then it was an unusual size.

[Scott_Conger]

Wayne

thank you very much for that. I had no idea that those studs changed...now I do.

[KimDobbins]

In a letter from C H Wills to the drafting department dated Aug 31, 1909.
Kindly note that we have changes T-184, drive shaft tube flange from special to standard 3/8” castle nut. Also changed T-183 drive shaft tube flange stud to correspond with above change.

[Wayne Sheldon]

Kim, Would that be when they went away from the earliest Babbitt driveshaft bearing, and to the roller bearing in the spool mounted on studs?

[RGould1910]

Thank you. Part of the mystery solved. The nut is a 3/8 inch castle nut. I still wonder if the thread size is 24 tpi. I suspect it is because the other end of the stud is 24 tpi. Why would Ford have two different thread sizes on the same stud? Reason I ask is because I was informed by a knowledgeable person some years ago the size at the nut end was 16 tpi.
I just want to make them right.
On another note, the reason Ford went to a 13/32 " stud rather than 7/16" is because he did not want to change the spool or the flange of the rear end housings where the studs enters or the lip of the torque tube. The stud holes in the spool would not accept a 7/16 stud, but it would accept 13/32. Ive owned examples of the first spool Ford used with 3/8" studs, T 191 and it bears out what I say. There is not enough material in the spool to drill the holes larger to accept a 7/16 stud without drilling into the flange of the spool or the recess in the rear end housings.

[KimDobbins]

I’ve had at least 1 early spool where the drill/ machining process came through the outside of the casting. Most all the Ford information says the change from the Babbitt rear drive shaft bearing to a roller bearing was at car number 15,000.