I have the accessory stop/tail light offered by Ford in '26/'27 which uses two bulbs. I have the bulb that illuminates the portion of the lamp with the "stop" stencil but do not know what bulb to use for the bottom tail light portion. The contact is offset so a single contact bulb will not work and all of the dual contact bulbs that I have are too big to clear the lens when the lamp is assembled. It is hard to get 6 volt bulbs these days so I was hoping to find a 12 volt bulb that would work assuming the candlepower is sufficient to give enough light at 6 volts. In any event if I can get a number for the bulb I need in either 6 or 12 volts perhaps I can track one down. Thanks!
I was amazed the selection of 6 volt bulbs the local NAPA auto parts warehouse store had. I had to go to the warehouse store to get them, not one of the smaller neighborhood stores.
We have a NAPA in town and they will try to get what I need from their distribution warehouse but I need to give them the numbers so they can order what I need. I have gotten bulbs from them before when I had the number of the bulb that I was looking for.
The smallest length 6V lamp is:
#63 at 3 CP (3/4 dia glass globe)
#81 at 6 CP (3/4 dia glass globe)
#87 at 15CP (this has a slightly bigger globe spherical -1" diameter)
All these are single contact opposed pins. You have offset pins in your sockets…different story.
Also, don't try to go 12's on a 6V circuit. According to the lamp rerating guide, you'll be lucky to even get them to glow more than a red filament.
George, I am using a 12 volt bulb in my dash light and it is just fine. I am no electrical wiz but I assume that the output at 6 volts would be half of the same bulb at 12 volts. I wonder if anyone has the Ford spec for the bulb that is called for in my taillight. A dual contact dual filament bulb works fine but won't clear the lens. Someone out there must have the same set up I have and figured out what bulb is needed.
I'm sorry I don't have a dual tail light to reference. The vendors apparently carry what you want, both in straight opposing pins and offset pins,but they only carry them by their internal part number.
I can't find anything in the lamp interchange tables that even comes close.
Actually, back to your question about a 12V 'find'. The lamp resizing charts are not linear. For a halving of the supply voltage to lamp voltage, the CP is divided by 10. So if you had a 15 CP 12V lamp in the dash, you'd still get 1.5 CP out of it at 6V. If you had a 3CP 12V lamp...on 6V it would be 0.3 CP, hence my barely glow comment.
I am pretty sure both bulbs are center contact with even pins. You might want to take another look at the contact in the lower socket. It would only light up when the tail light is on, unless someone has changed it.
The socket the plug fit into on the back has two contact, one for the tail light and one for the brake light.
I will look at the one I just got tomorrow, it's at the shop to make sure, except for age and wear does not look molested.
George, thanks for that clarification, as I said I am not very good with electrical issues but I think I understand what you are saying. I guess the lamp I am using in the dash light is large enough that it is adequate at 6 volts.
Mark, I would be interested in seeing how the inside of your lamp looks. I do not think mine has been tinkered with but you never know. The way mine is set up both wires run to the lower tail light socket but there is a solid copper bridge that shunts the brake light wire to the top socket. I really need to figure out how to post pictures one of these days but what I don't know about electrical issues is exceeded only by what I don't know about computers. I have considered replacing the socket but I do not want to alter the lamp if it is an unmolested original.
It's not original. Someone doodled with it in the past. They changed the lower socket to dual contact as Mark noted. Perhaps an attempt to make running, stop and turn signal lights on separate circuits. Then someone added a jumper. Might even be a converted Model A tail light but without a picture, it's just a guess. Are there any markings stamped into the body of the light?
This is a picture posted by Gary White last year. Does your light look like this? It should also have a clear lens on the bottom for the license plate.
I looked at the light very closely and doubt it has been modified. I am going to try to post a picture. There is no doubt in my mind that it is the Model T accessory tail lamp. It is not set up so that both bulbs go on when you step on the brake as the second contact point in the lower bulb is not designed to make contact with the lower bulb. Using a dual filament bulb the tail light works when the lights are on but the second filament does not go on when you step on the brake. I would leave it like that but the bulb is too big to clear the lens.
Ken I can't get a picture to go through. I will try to email one to you and perhaps you can post it for me.
Ok, now we're on the same page--I got your pictures. Yes, that is the Ford accessory light made by Hall. I can't help with the correct bulb though. Perhaps someone that's using the light will see this. I've seen a number of threads on the light but no mention of the correct bulb.
Thanks Ken. Hopefully some day I will be able to figure out how to do what you just did!
Come to think of it, that looks like it would take a "standard" 21/6CP Model A tail light bulb. The Model A tail light bulb will work. It's sold as part number A-13304 (Snyders). It has no modern equivalent that I know of.
It's a dual filament, dual contact but the way the socket contacts are made (only the bottom makes contact*), the upper bulb will be the brake light; the lower bulb only uses the running light filament.
*The bottom contact in the lower socket has a spring backed pin. The top contact is more like a rivet and doesn't extend high enough to make contact with the bulb.
Val - Email your address. I'm looking at one in front of me right now. I'll try to get it mailed tomorrow morning. Put a order in later with other parts for a spare. Shipping on one bulb would be a deal breaker for you.
Forgot to mention, it is the small globe bulb and should fit. I just took a picture of it so that anyone else that may be looking for the bulb knows what to ask for.
For the lower bulb socket, the tall contact/pin has a slight angled up and to center and only it makes contact with the bulb. The upper contact which is the bridge to the stop light does not connect to the bulb, it is lower then the long pin/contact. It would use a 63 or 81 single contact bulb. If your pin does not touch the center I would suggest adding a glob of solder to the side that would. The bulb in above photo will not work, it has staggered index pins, the socket in the lamp does not, in fact, if you look at the lamp the index pin slots in the socket would not put the bulb on the correct axis's they are not at 90 deg. to each other, where as the single contact bulb does not matter.
I think you're looking at the bulb insertion slots that are 30 degrees off axis. When the bulb is turned, the contacts are aligned. But you're right; if the socket pin slots are the same depth, the bulb will not work.
The socket contact pin doesn't look angled to me and I'm pretty sure "a glob of solder" was not part of the design.
The unmarked bulb that was in the light when I got it had one of the pins filed off so it may have been the bulb you say is used on the Model A lamps. The bulb was blown so I don't know if it worked that way.
Mine is angled, hard to see in photo. At 600+ it was easy to see, reduced to 33% not so good. Yes contacts are aligned.
You're right, yours looks angled. Perhaps someone bent it over to use a #63 or #81 bulb. Might be a solution for Val if done carefully.
I looked at mine very close, it was made with an angle to the pin hole, the pin is not bent. When they put the hole in the fiber block the one for the tail light bulb was made so it contacted the bulb almost in center and used a standard plug double contact plug on the outside. I took more photos but first I need to get hard copies made before I down load to photobucket. I can only get my camera down to the 600+ range and takes to long to resize each picture to post here.
I am reluctant to start tinkering with the pin in the tail light socket but the way it is located in the socket I doubt I could bend it enough to make contact without breaking it. I am going to try to tweak the pin a bit and drop some solder on the contact point of the bulb. I would like to see your pictures however Mark as I am wondering why I have an issue in the first place if my lamp is correct. I am thinking that someone must have tinkered with it at some point.
Another thought, if someone has changed the socket or guts you could solder a brass washer on the base of the bulb for a bigger contact surface. You would want to use one that keeps the bottom profile on about the same level as the original contact and keeps well away from the sides of the socket. Maybe one for a No 10 screw might work.
You might want to do a couple bulbs for spares at the same time. I would not mess with the pin at this point.
As an experiment, that's exactly what I did yesterday Mark. I punched a 7/16" washer out of brass shim stock then a 1/8" hole in that. It soldered to the bottom of a #81 bulb perfectly. I used .010" shim stock but a thin washer may work too.
I was thinking about something like shim stock but suggested washer so it would be stiff less likely to bend. At least we are thinking along the same lines.
This morning i dripped solder over the bulb contact and that worked but then I decided to try and make it a better fix so I soldered a small piece of round stock to the bulb contact and it worked perfectly. I noticed that the pin had a bit of up and down movement and suspect that the problem initially was that the pin had gotten loose in the socket and dropped down so it was no longer angled up the way Mark's is. In any event, it's working now and I made up a couple of spares to carry in my Ford emergency tin! Thanks again to everyone for all the help.
I converted my '25 stock tailight to a stop light. They aren't real common, but I've found a number of FORD replacement tailight assemblies that use a bulb socket similar to the headlight. With this arrangement, I am able to use one of Snyders bulbs pictured above, but I have to file the offset pin off for it to work. I then use a kinda standard connector that has two spring loaded contacts on it. I've seen hundreds of these at swapmeets over the years. This way, I have a stock appearing tailight, and license plate assembly, but I have a stoplight too. I use an original Ford stoplight switch attached to the bendix cover. Works great.
Here's a couple photos of my totally original & unmolested '26-'27 Ford accessory stop light. The lower contact is most definitely positioned on an angle and what appears to be the original Westinghouse bulb is a #63. The upper (stop) bulb is an original Westinghouse 1129.