MTFCA Forum

I finally found top sockets for my 24 roadster. My new crisis is that I ordered top saddle support arms https://www.modeltford.com/item/3858B.aspx

The reproduced arms have an 11/16 fine thread. They would not screw in and when I looked into it, the area where mine screw into are either 1/2 or 5/8 coarse. (I dont remember which)

ANYWAY. Does anyone have information on the thread differences. Are the coarse thread arms available??
Thanks.

Tom, I am in the same boat.

ADDED 4/4 23:
[Correction, although a 5/8 bolt will screw into the hole it will slip when tightening, so the hole is larger than 5/8.]

Looking at period and factory photos it appears the top saddles and arms were not installed at the factory and a rubber plug was covering the hole in the body. If the arms and saddles were supplied as a loose part or in a bundle with the tool kit, is anyone's guess, I have not found any documentation either way. One factory photo shows the 15th million T getting its arms and saddles installed at the end of the line.

Thanks again Jeff.

I am going to see if the 11?16 could be turned into 5/8 by my machinist. I am sure he will think of something. I will let you know.

Posted new information after doing some checking.

The description in their catalog says 11/16.

I just assumed they would work I guess

All 4 that I have, 2 fender supports and 2 for my roadster top rest, are 16 TPI. Mine measure about between .665 and .675 on the outside of the thread.
There is a good possibility that the ones you have are correct and there are issues with the holes you are trying to screw into. Don't know, can't see what you are working with.
Added more information in my post down below. There is an 11/16 X 16 TPI tap made.

tap drill for 3/4" thread: .656 (coarse), 21/32 (fine)

FWIW, while not common, 11/16 diameter can be found in 11,12, 16, 20, 24, 28, 32 TPI (just in American sizes...a couple more in British sizes)

11/16 might not be found in standard tap/die sets, but that only means the set is incomplete due to low use of that size

I just looked on line and found one on MacMaster Carr:
https://www.mcmaster.com/taps/thread-size~11-16-16/
Yes, there are lots of other sizes, not all are listed on most tap/die/drill charts.