The guy wHo decided that the generator output terminal on a T should have a 1/4x24 thread ought to shot. The only other places I have encountered this thread was on a phonograph crank and on a helicoil. I can forgive the Helicoil guy as the thread had to be the same as the screw being replaced. I was going to blame Henry and Edison for playing a mean trick but the phonograph was a Victor.
A 25 cent nut and bolt now cost $10.00
Based on the $10 evidence, perhaps the plan worked. :-)
Actually, you've just stumbled on one of the beautiful things about standards: there are so many to choose from!
A cursory search of the Internet asking about thread standards was very informative. Threads were first standardized in the US and Britain in the early 1850s-1860s. Britain was first with the Whitworth standard. The US followed with the Sellers standard in about 1865. The two threads are quite different. In the days of the early automakers there was more variety available in threads - form and pitch (inverse of threads per inch [TPI]). The 1/2" coarse thread still comes in both 12 and 13 TPI.
By World War II, it was discovered that the differences in very basic threaded parts were a terrible burden to the war effort. Apparently there is a treaty in the works that may be approved any day now, to coordinate the US and British standards into one system.
So, how does this help your generator? Simple, find something else that uses a 1/4-40 thread. A quick look found the small bushing toggle switches have a 1/4-40NS thread.
You can buy the whole switch at Radio Shack for under $3.00 US. But, you probably have a number of them in your "spare parts box."
There is also a 14-24 thread with a diameter of 0.242” that is a member
of the ASME thread class (American Society of Mechanical Engineers)
which covers the more common 6-32, 8-32, 10-24 etc sizes.
Several years ago, I went to a hardware store to buy some 14-24 bolts and was told rather nastily that I was stupid and that there NEVER was such a thing by an experienced (?) clerk. With other customers watching, I walked that clerk a couple isles over and asked him why the store was selling taps and dies for a size that never existed. The point of this, is you have to research these odd sizes, because even most experts (?) today do not know what they are talking about and won't be helpful. There are many "close fits", including metric, that can be made to work easily. Another one to look at is parts in the lamp department. Some of their threaded tubing and other parts are the same size series as the switches.
And if you think Ts are tough. Many even earlier automobiles, buggies, and other things did not use standards. A nut and a bolt were hand-cut to match. A couple of times it has been nice having some antique thread-cutting tools to hand make replacements.
Have fun, and drive safe, W2
Donnavan needs to restrain his comments. It would help if he did just a tiny bit of research on screw threads in common use 75 to 100 years ago. This is a hobby for Pete's sake.
I agree totally. Many will have apathy for him anyway.....
Cecil, I just looked at your profile, Where did you purchase that wheel chock :-) Rick
I had one of those wheel chocks once. I found it along the road.
The 1/4-24 may have been a very popular thread back in those days.
There is wierd size bolt holding the tail lights on on '41 Buicks. About 1/4" but no hardware store I could find had them or could help.
You need to look at the complete generator output terminal bolt design.
The bolt is expensive not because of the thread size, but because it has a square shank that interfaces with the main brush output wire terminal end and the generator case through wall outer insulator. This was done so the output wire terminal and bolt would not turn in the bore and short inside the case.
For these reasons the bolt has to be custom made ($$$) as no standard 1/4x24 bolt would work.
Ron the Coilman
I guess you guys just dont get it....
Maybe they don't like whinning? Ron gave him the correct answer. The way people start their threads actually invites sarcasim. The way the question should have been asked was "why is the generator output terminal made the way it is?" "Are there any options?".
You hit the nail on the head!
At least we now know that Donavan has zero regard for engineers. He should be happy to know that he isn't alone here feeling like that.
I always use carriage bolts 6 mm x 25 mm for 25 cents. works for me
Carmakers have several kinds of engineers.
Design engineers fit the needed and desired parts into the package created by Marketing.
Reliability Engineers balance the cost of possible component economies and improvements with warranty cost.
Value Engineers beat the cost out of the components. A dime saved on ten million cars is a million dollars.
Maintainability Engineers are dedicated to keeping warranty costs down.
It's up to management to balance the above groups to make a car profitable.
Therefore, a car with 100K mile warranty should be about three times as reliable and lower cost to own over its lifetime as the car with 36K mile warranty.
On this side of the pond, metric carriage bolts are about as rare as hen's teeth.
Have a greaT weekend,
Well,to begin with cost would more manageable if 1 standard was used in all manufactoreing as far as thread and bolt size goes.Before metric came along,America was doing just fine,we had all kinds of odd ball crap allready, but no,had to throw in another intire measuring system.Thank goodness it came after the T.
Bolt threads.I know Ron has it right that the particular bolt in question is of a special design and probably hard to make.But when it came to the threads,they could have been a standard type,no need for special stuff.Similar problem with the bendix cover bolts.Why?I am sure there are storys and "reasons",but none really make sense if saveing money was the idea.A standard bolt coulda been used that a million boxes were allready on the shelves.
I have had my backside chewed by several engineers on here so most people know how I feel about them.
Basic problem here and over on the FB V8 board is folks that do not do their research. If one is going to buy an old Ford, first thing they should do is set up a library with parts books, service bulletns and after market professional publications and use this library. They just do not do that. You would think that a 10K up investment would be important enough to research. Seems like a lot of V8 buyers are intent on butcher work only and apparently some T buyers.
It's a Ford; live with it. Fixing anything on a Ford takes every wrench in your garage, and you often have to go buy another.
I was agog after years of VW, Corvairs, etc., that it took seven different wrenches to remove the alternator on a 1986 Sable (Taurus). And the alternator is right up top. I ranted about the stupid modern Ford Co.
Then I got a T, and learned how it all came about. The hardware is sized just large enough for the job at hand, without regard to standardization for inventory or convenience of maintainability. Actually, it's a good plan so you are not carrying unneeded extra weight for the life of the car.
Actually two nuts are required on this costly carraige bolt.
And yes I was an engineer but of the electronic variety
Just maybe 24 tpi was the finest they could go with the metal they used. 20 tpi is coarse, weaker than 24, and more prone to back off. 28 tpi might tend to strip with torque from the standard length 7/16" wench.
The engineer who designed the generator, if he is still alive would be at least 99 years old if he had been 20 in 1919. Do you really think he is still alive? If so, why shoot him? It's just too late.
I'm sure there are enough used generators around that you can find one used bolt.
Get over it!