Observations

[Original Smith]

I've been helping a friend with information on his original 1915, and here is where I'm at. We are working on ORIGINAL throttle rods that go through the block. What I've found out is the material is 7/32 diameter, and this size was used throughout the entire Model T production. It also appears the alloy has a high nickel content, and was made from the same alloy as the steering shaft and spark and throttle rods. This car also has the adjustable throttle elbow on one end with a 12/32 thread.

[Wayne Sheldon]

Interesting and valuable information!
Thank you again for your efforts to figure out what is correct.

[KWTownsend]

Larry,
Which end of the throttle shaft has the adjustable end, the steering column end, or the carburetor end?

[Allan]

Once a rod gets to be smaller than 1/4" there is every chance it reverts to a wire gauge size, like the spokes in wire wheels etc. Threads on these are usually rolled threads rather than cut threads. They are often not related to cut thread sizes/pitch. It would be interesting to know which wire gauge is equivalent to Larry's throttle rod.
It would make sense for Ford to standardise on a single size wire for such connections, throttle rod, timer linkage etc Using wire gauge threads may account for the odd sizes. To lock the swivel end on a throttle rod, in the absence of a nut which fitted, I have used portion of a spoke nipple at times.

Allan from down under.

[Original Smith]

More observations. I believe the rods were not painted, and were left natural as the steering shaft, and spark and throttle rods on the steering column.
Next, the elbow for the throttle shaft is on the drivers side, not the carburetor. The threads on the early cars are #12-32. The Ford book says there is a jamb nut for the swivel, but not for the throttle rod. Owning an unrestored 1914, I can assure you this was a mistake. A jamb nut is essential to eliminate vibration, which wears down the threads.

[hull 433]

The original rod and adjustable end on my car had no traces of paint when I got them, and were a bright finished metal once cleaned. They seem consistent with the unpainted steering shaft. Wondering about the commutator rod now.

The adjustable end 3538 looks like it was phased out late 15- early 16. Exactly when I don't know. It's listed in 1916 parts list, but with a note to use the new one-piece 3535 rod instead.

[Ron Patterson]

The original Ford print for pulls rod indicates 7/32-32 threaded end which was the same as 12-32 thread.
Many of the parts for early Model T's were designed by engineers trained in Europe who were very familiar with these standards.
As has been pointed out here Henry Ford was the first leader if the SAE, but the SAE Standardization Committees came later.
Ron Patterson

[James_Lyons-WV]

Pictures of the throttle rod and spark rod adjustable ends on my unrestored 1915 Touring, no. 679,2xx. Adjustable ends are at the steering column side. The rods appear to be bare steel and there are no jamb nuts. There are two different adjustable swivels - the timer rod has a ball joint with a nut affixing it to the steering column lever where the carburetor rod does not. It is held by a cotter pin. It is possible that the adjustable ends may have been black painted, but I would need to clean the goop off to be sure. You can really see it on the carburetor end, under there layer of grease. I will try to clean them later today to confirm. There are no adjustable ends at the timer side or the carburetor.

[RGould1910]

Interesting info. I thought the adjustable swivel on the carburetor rod was where it fed into the carburetor shaft.
Is what I read true for 1912 cars?

[Original Smith]

I'm no expert on 1912's but I would assume they are the same as 1913 and 1914's.

[Original Smith]

Another factor on the throttle linkage, would be the carburetor. Those throttle arms could be slightly different from carburetor to carburetor.

[Original Smith]

On a similar subject. The carburetor mixture adjusting rod. The diameter of this is 3/16". For the early cars it has a forged end welded to it, about 2" up. Some have a factory number on the forged end, and some don't. The diameter of the forged end is about .009" larger than the upper portion of the rod. Some factory photos of this rod show it to be a natural finish, and others show a black finish.

[hull 433]

Here are two 1914 assembly line photos from different angles, showing what looks like an unpainted adjusting rod. One 1915 factory photo shows what looks like an unpainted rod, while another on the shipping dock seems to show one painted. A garage repair photo seems to show unpainted but its hard to be certain.