odd ball sockets sizes

[Jerry Roberts]

I needed to replace my brake light switch so looking through my various sockets , the only one that would fit is a size 31/32 . I couldn't use it because it wasn't deep enough because of the prongs on the switch and I ended up using a needle nose vise grips . There used to be a hardware store here that had ' open stock ' sockets ' in the larger odd ball sizes . Reading about Henry Ford tells me that he made some of his fasteners in unusual  sizes so that he could sell his own Ford brand of tools . 

[Loren]

I was working on a Model T and I needed to know the center to center distance between the crankshaft and the camshaft.

So I went to the Model T Ford Club website for that data.

What I found was that some member had measured a dozen blocks and came up with a range of numbers carried out to 5 decimal points!

Since Model Ts have poured babbitt main bearings I found that crazy.

Poured babbitt bearings are reamed with a line boring bar that registers off the cam bearing bores in the block.

It uses a "false cam" and an arm front and rear to align the crank with the cam.

If you know what the desired measurement is you can figure a tolerance + or -.

An average of the range of 12 blocks gave a number that did not make sense. No engineer picks a size that requires 5 decimal points to express especially when the measuring equipment of the day could not measure better than 3 decimal points.

I went to my decimal/fraction chart on the wall and found exactly what I was looking for.

The Model T measurements were in fractions not decimals because that was the best measuring equipment they had then (the period of around 1906 to 1908).

The closest fraction size gave me what I needed to know plus I could guess a tolerance.

The decimal guess of the Model T club member was a little off to one end of the range. If I had made it the average the cam gears would be noisy or they would bind.

There are a lot of odd ball stuff in automotive engineering.

Check out the oil tube between one side of the Plymouth block to the other. That is an unusual size for which you can't buy fittings for.

 

[Bryan]

Some times a metric socket will fit when the bolt head is worn (or odd).

[Plymouthy Adams]

Walter would have gone tits up in the tools business......as mopars have a big advantage over Ford and GM....they simply keep running....

[Racer-X-]

15 hours ago, Bryan said:

Some times a metric socket will fit when the bolt head is worn (or odd).

I had the same thought.   For 31/32, a 25mm is only about 0.016" too big. Although 25mm is pretty "oddball" in the metric world, so I don't know if that would help.

[Sniper]

Vice grips fit any size, lol.  I ran into one of those oddball sized nuts working on a Model A recently.

[Dave72dt]

A 6 point 1 inch socket probably would have worked

[capt den]

i always buy the oddest size wrenches i can find at the flea markets. i find them in the piles that vendors lay out that are a pain to look through.   capt den