Thread Size, Early Spark and Throttle Rods

[Original Smith]

For years, I've been using coil point nuts as a jamb nut for the spark and throttle rods on my early cars. I don't know if Ford did that? Next question is what is the thread size? I'm thinking 12-32? If a jamb not isn't used, the vibration from the engine will eventually wear out the threads.

[Scott_Conger]

Has been discussed many times on the forum.

Just takes some homework.

[Ron Patterson]

Larry
The thread size on the early Model T spark spark lever swivel (Ford factory number T-1326) is 7/32-32.
As you know the coil point 12-32 mounting nuts will work as jamb nuts.
Ron Patterson

[Allan]

Ron, is 7/32 equivalent to a particular wire gauge? I have found wire spoke nipples wit the same thread as the linkages. The threads on spokes are formed with rollers rather than cut using a die. I believe the same rollers are used on a number of different gauge spokes, so the thread count stays the same but the diameter differs. It makes mixing and matching difficult at times.

Allan from down under.

[Original Smith]

Thankyou Ron! It can't be a very common screw size, as I've not found that size in my can of machine screws.

[Henry K. Lee]

Yeah they are available. I bought out old hardware over the years but to those that show kindness, manners, and an open mind to others the payment is normally free. To others that show very little respect, keep looking.

Hank

[JunkyJud]

I rarely visit the forum anymore because of the atmosphere but when I decide to, I just look at Larry's posts to see if the same butt hurt responders are there. I'm never let down.

[Jerry VanOoteghem]

I rarely visit the forum anymore because of the atmosphere but when I decide to, I just look at Larry's posts to see if the same butt hurt responders are there. I'm never let down.

Well, I guess if you're looking for negativity you can find it just about anywhere.

[Ron Patterson]

Larry
Here is the way those commonly found oddball thread sizes used in Model T's was explained to me. Many of the engineers who worked on original Model T design were trained in Europe. The oddball thread sized you find on Model T's; 7/32-32, 14-24, 12-32, etc were common in Europe.
Although Henry Ford was the first President of the Society of Automotive Engineers, the SAE standardization committees did not conclude their standardization efforts for the automotive industry until the late 1920's and early 1930's.
Ron Patterson

[Scott_Conger]

Ron

while I agree with everything you stated, one nit I'd pick is this: those sizes were likely not just Euro-centric. I believe that they are as American as Apple Pie.

Working on carbs, one must have every tap/die known to man, and a few known only to the Good Lord himself. Every size tap/die you mentioned above can be found in a mint Greenfield tap/die set that occupies one of many slots in my inventory. They are very plentiful on the eBay tool market and are all inexpensive and in-stock brand new on the tool suppliers'' shelves. That just doesn't sound like something that is old-world or rare in application during their hay-day...odd-balls now for sure, having been winnowed out through several standards changes, though. Just an observation...

Always enjoy and appreciate reading your posts

[Original Smith]

I'm really glad I started this thread. I'd like to add a couple more comments. I did see the 7/32 screw size in a 1916 parts book, but only for the swivel joint. I've found that nut to be needed for the throttle rod too, which is not noted in the parts book. I have what used to be a mint throttle rod. I see in the parts book, it is called a carburetor pull rod! At any rate, because the jamb nut was not used on this rod, the adjustable end can't be used because the threads are worn out from being loose. It's a good idea to use a coil point nut as a jamb nut for this rod. Does anyone know whether the adjustable end was used? At the carburetor, or the steering column? This is all trivia I know, but that is what I like.

[KWTownsend]

Larry,

I believe I read somewhere, or saw an original image, that the adjustable end was used at the steering column end. That being said, on my cars I have the adjustable end at the carburetor end. I find that location much more convenient if carburetor swapping occurs.

: ^ )

Keith

[Allan]

Keith, on our RHD cars the swivel end is on the right side of the car, quite near the carburetor. Because of the twisting change in geometry between the control arm on the throttle rod and the arm on the carburetor throttle rod, the swivel end needs to be fitted to the steering column end.

Allan from down under.