MTFCA Forum

Quick question: what are the differences between 1915-16 headlight and the later lights? I've noticed that the position of the screw is on top. Can a later headlight be converted to a 1915 style by rotating the light bulb socket, so that the screw is on top? I need a pair of 1915-16 lights but I only have one with the screw on top. Why did they change the position of the screw anyway?

Those early lamps used a single filament bulb, so the collar in the hole has adjusting slot positioned for the screw drive adjuster of the bulb socket. Later lamps use the Tu_lite bulbs, with dim and high beam filaments, so the side screw type housing came about.

Early lamp
Early lamp housing
Later lamp , note the slot for the adjusting tab on the bulb socket, that slot has to be oriented to the tab of the bulb socket
The collar fitted to the bucket is sort of pinned or pinched, it determines the position of the lamp socket. That collar has cutaway for the action of the socket going in and out to adjust the beams.
IMO, would try to find a matching set of buckets, they are available from 1915 to 1920 or so.

Rick send me an email. I may still have one Dan

There is another other subtle difference that has done unnoticed. An original double filament 6V bulb has two "A" shaped filament such that the pins in the body would cause these to be oriented horizontally when inserted into the headlight socket. This configuration is a BA15D (BAY15D has two offset pins). --

I have two different double contact sockets, such that the orientation MAY be compatible with the different position of the headlight adjusting screw location. I came across the difference in cleaning up a bunch of sockets. I just came across some 1915 headlights that I have yet to take apart to confirm a difference, --
As you can see the two different adjusting screw positions result in their contacts being in a vertical position. So moving the screw may require a different socket if the headlights can't be focused correctly.

There were some 1915 headlights in my Barn Find. I will need to take them apart to see what sockets are being used.

The adjustment screw was at the 12 o'clock through at least the 1917 model year and the headlamps are not as scarce as one might think.

If you are stickler, you should have a matched pair made by the same manufacturer. For example, the headlamps on my unrestored May 1917 roadster are John Brown while the headlamps on my father's July 1917 touring are E&J.

The headlamps with the adjustment screw at the 9 o'clock position may have been adopted early in the 1918 model year in conjunction with the change to the combination horn button/light switch-dimmer which I believe was around October 1917 based on some posts by John Regan and a surviving, early 1918 touring which still had the light switch on the firewall.

For 1915, 1916, and into 1917, the headlight focus screw is at the 12 o'clock position:
Notice the contacts are in line with the focusing screw.

If right angle headlight connectors are used and the wrong sockets are used, the right angle headlight connector will sit 90° off
These used a push-pull headlight switch. The rectangular switch is "pull on, push off" the round switch is "push on, pull off."
Late in 1917, the combination horn and headlight switch was introduced. The headlight switch as three positions: Off, On, and Dim. A resistance unit was mounted on the firewall. The theory was when driving at high engine RMS, turn the headlights to the resistance unit position to help keep the light bulbs from burning out.



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Keith

The adjustment screw was at the 12 o'clock position through at least the 1917 model year.

The combination horn button/light switch and dimmer coil on the firewall was introduced early in the 1918 model year (the fall of 1917).

Erik,
Thank you. Corrected.
Here is a wiring diagram for the resistance unit:
How long were the right angle headlight connectors used?
Were they on Rip Van Winkle?


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