MTFCA Forum

My car came with an after market ignition switch. In a box of parts I found the original switch still mounted in the backing plate. I suspect it's easily restorable. My question is, how do I determine what key it takes?

If it is an original switch and has the later type key which is two sided with a slot on one side, you should have a number stamped on the front of the barrel of the switch. The key is the same number. Let me caution you, however, the reproduction keys are not always ground exactly right and you might find one key with that number which works fine but another with the same number which will not turn the lock.
Norm

Thanks Norman. That's the answer I was expecting. I initially looked at the tumbler and thought I saw a number but it's very faint. I'll look again, maybe borrow some younger eyes

SteveD wrote: ↑

Thu Mar 30, 2023 12:09 pm

My car came with an after market ignition switch. In a box of parts I found the original switch still mounted in the backing plate. I suspect it's easily restorable. My question is, how do I determine what key it takes?

A photo of what you have would be best to guide you
There were several manufactures of the rectangular (1919-25) switches. There are differences that in these that make restoration easy to very difficult. In general, those with just 2 rivets holding the metal cup containing the switch parts to the plate are the easiest & have some parts available for restore (the back plate, T5012, being either the pin or clip type, and the switch tumbler). The internal parts are different thicknesses for the pin & clip types. Replacing/refurbishing the back plate and cleaning up the internal parts are a relatively easy task. Replacing the tumbler or removing the switch handle can be a little difficult to very difficult (requiring removal of the metal cup & replacing the rivets).
Here are some pictures
These are the ease two rivet faceplates - they can have either a pin or clip type back. --
The reference to the back plate being clip or pin & the differences of the internal parts are shown here These parts fit in between the square disk and back plate & there differences relate to the switch handle differences and not pin or clip type. They should match the handle tabs. --
Now the way the handle is attached to the two rotating disks identifies if the rivets need to be removed in order to replace the tumbler. If you see the the handle tabs bent over the large rotating disk, then there is no need to remove the rivets --
The repro tumblers require some fitting into the small disk - I need to get a picture of that...
Also if the backing plate is not warped it is likely good enough to use by just giving the inside face a light sanding and cleaning the contacts. It is not recommended to bend the spring contacts

My question was about the key, but this is a lot of useful info. Thanks Frank

The repo switch cylinder is also too big around to replace an original tumbler.

I suspect the likely original pot metal sample used to manufacture a mold was unknowingly enlarge way too much from moisture absorption.

SteveD wrote: ↑

Thu Mar 30, 2023 4:13 pm

My question was about the key, but this is a lot of useful info. Thanks Frank

I wasn't sure what you found and what you were intending to do with it. But if it wasn't installed then it may have an issueto resolve
The key ID is as noted above. The original tumbler were made out of pot metal like material and often they crack. It may be the reason why it was replaced. Also these "tumblers" have wafers in them that align with the key cuts. Sometimes these fall out of position & then either any fey will work or no key will work. And yes the repro's are a bit too large and the hump on the end of the tumbler that inserts into the small disk is slight offset & fatter. The oversize issue is a result of wafer groves have a stop fro the extra material to prevent them from falling out the bottom, but not the top if turned upside own.

Norman Kling wrote: ↑

Thu Mar 30, 2023 12:15 pm

If it is an original switch and has the later type key which is two sided with a slot on one side, you should have a number stamped on the front of the barrel of the switch. The key is the same number. Let me caution you, however, the reproduction keys are not always ground exactly right and you might find one key with that number which works fine but another with the same number which will not turn the lock.
Norm

There have been several improvements made to the reproduction keys. A lot of effort has gone into making sure they are “ground exactly right.” More times than not, the 100 year old pot metal barrels that are worn or swelled are the cause of fitment issues, not the new keys.

H. H. Franklin of the Franklin Automobile Co developed the die-casting process into a useable industrial business. He needed it, as Franklin was the largest user of aluminum in the U.S. in the early years of the century. Franklin originally bought the process from it's original inventor right after the inventor came up with the process. This happened before Herbert Franklin ever got involved in automobile production.
One of the key ingredients in die casting is the addition of zinc to the material mix, which makes it easier to mold the metal, (OR easier to use a bad mold in casting the metal.) Generally, the worse the original mold quality is, the more zinc was added, and the worse condition those parts are in today.
Franklin knew die-casting backwards and forwards, and used minimal amounts of zinc in Franklin factory die-castings. EVERY SINGLE Franklin DIE-CAST part on my 1926 Franklin is still in perfect condition.
HOWEVER, parts that were supplied to Franklin by outside vendors, (such as the speedometer assemblies, and the fuel gauge assembly that screws into the fuel tank) were obviously made with high-zinc content, as they are in a terrible state.
Zinc is a metal that never sleeps. It is constantly active, from the first day the casting is poured. Cheap die castings with a high percentage of zinc tend to swell and deform. They also will crack and split, and start to deteriorate from the inside out, eventually becoming so delicate that even gentle handling will shatter them. Die-castings that have a minimal amount of zinc are much more stable, and can last for many years.

Frank:
Thanks for sharing all the switch info and including the excellent photographs. In my opinion, this would be a useful technical note for The Vintage Ford, assuming they and you were willing to make it happen. Meantime, I'm archiving your post in my technical library. Best, jb

I've seen a lot of old, poor quality die castings crumble and fall apart. Indoors or out, it doesn't matter. Often, other die castings in the same piece of equipment are as-new. Pre-WWII radios and phonographs often had pot metal parts, and indoor storage did not proetct the vulnerable parts.