During our 22nd National Club Tour here in New Zealand we came across the following KW coil. As you can see it is NOT for a Model T, and appears 'factory made' in the configuration shown.
For a bit of a challenge, what do you think this coil was for? Electric fence unit? WW2 Flame Thrower? or maybe just a Spark Plug Tester? a Single Cylinder Engine? or maybe a device to surprise unwanted intruders grabbing the door handle?
(Top to bottom it reads: "Timer", "Battery", "Plug")
Most likely for an old engine.
Lots of old engines used buzz coils to provide spark because they were much cheaper and simple to energize.
Fairbanks Morse, among many others, simply added a peg on the camshaft gear that made contact with an electrically insulated "hot" metal strip to momentarily complete the circuit.
This worked very well on throttle governed engines.
What is very interesting is the metal angle bracket under the point gap adjustment probably to prevent the thing from being screwed down to totally close the points. The manufacturer was protecting the coil from customers who didn't read the instructions. Reducing the gap too far can permanently close the points and the next time a battery is connected the coil will have extremely high DC current and likely be ruined. Never short the points out on a T coil since that defeats the coils defence against wiring shorts in the timer as well as too much DC current in general when something gets crossed up. If coils can't buzz they can't survive our mistakes. My bet is if Ford had not used points to buzz the coil but instead had tried to use just the timer to set the dwell and to fire the coil then good T coils would be somewhat rare today instead of being plentiful.
I agree with Craig. Lots of hit-miss-engines, marine engines ect used this style coil. They called the coil style ignitions "make and brake ignition" in their ads .. Since most engines did not have a wiring harness like cars had. The just had individual wires, and the coil just laid loose in a box of some sort. The clips on the coil made a quick hookup easy...
Didn't the "Fairmont" railroad jigger use 1 or 2 of them coils?
NOTE: we called then jiggers but I don't know the proper name for them little scooter things that ran on the track and was used by work crews for transportation and to pull a small trailer or 2.
Those were Fairmont F7996 coils and I make them.
They used the same points as a T coil but were a different box made from oak.
Ken - Most railroads and railroad people call them "motorcars" (one word). It seems that most people outside the railroad industry call them "speeders".
I think "jiggers" is an "Imperial" term used in (ex) British colonies for railway inspection carts. Motorcars were driven on the roads over here :-)
We think it is most likely to be a single cylinder stationary engine coil as well.