I would be very interested in seeing several closeup photos of an original 1920's 6V double filament headlamp bulb complete with markings (candle power) and the way the filaments are in relation to the contacts. Modern bulbs, when installed in the Model T socket are positioned side by side so that the different focal point of the bright filament is reflected further to one side or the other, instead of higher or lower as it should be, whereas they were originally positioned one above the other so that the upper filament has a different focal point on the reflector than the lower filament and the reflection of the bright beam is higher up on the road and shines further than the weaker filament. Is there anyway we can petition the bulb manufacturers to manufacture an accurate original bulb with the filaments one above the other, so that we don't have to remove and twist the sockets in our headlight buckets 90 degrees to one side or the other so that we can have proper bright beams that will illuminate in front of us for night driving instead illuminating the other lane and blinding approaching drivers? Jim Patrick
Jim, Good idea. I will be at Lang's barbeque tomorrow and I will ask Don't if anything can be done.
Sorry. I will ask DON, not Don't.
Even bulbs from the 20's/30's had different pin to filament orientation depending on the make of car/truck. I think one bulb from the 20's/30's, No. 1110 made by Mazda, would be correct. I am sure there might be more numbers depending on what number the manufacturer used.
I have a pair of Ford Script bulbs somewhere - I'll see if I can dig them out and get you that info.
What time will you be leaving Wayland to go to Langs? What route will you be taking? I am in Sudbury and thinking of taking my T there.
I've got a pair of Jaeger (sp?) Flamethrowers but I don't think they're from the period. By the name, they're probably from the late 40s or early 50s. The globe is a little larger than Ford's but still 6v.
Thank you everyone. I look forward to the results of your efforts in regards to pictures as well as what Don,s response is. It would be fantastic if he could have them made. I think all of us who have T's with electric lights could benefit from a new addition of an original type headlight bulb to Langs parts inventory. It seems like it would be a simple matter for the bulb manufacturer to reconfigure the filament location from side to side to up and down. Thanks again. Jim Patrick
PS. Does anyone at Lang's read the forum? If so, I would be interested in hearing from them in regards to what all is involved in the process of getting a new part in the works. I think a feasibility study would show that virtually everyone with a Model T with electric lights would buy a set of these bulbs. I know I would.
Oh yes, they read and pay attention.
I would buy a couple pairs.
Every now and then you get lucky if you troll T-bay enough, but you have to know what you are looking for...
I was successful in finding a set of original magneto lamps for the'15 last year simply because no one else apparently knew the lamp number as I was the only bidder so I received real NIB (new in box) old original Mazda lamps.
There was no 50/50 or 50/32 of the era...that's something that someone invented later and beware...if you get the same resistance on both pins...it isn't a 50/32.
The original Mazda lamp numbers were as follows...
I am not smart enough to know if the evolution of the number actually changed things over time. Technically, it should not! Sure the globe may have moved to a sphere glass or even a parabola, and the filament might be one of many different shapes...yet the "light center length" and rated CP would have had to stay the same or what good was an interchange manual, especially for trains, planes, and automobiles.
The original Mazda were most probably TeePee filaments as opposed to arch type, the lamp glass was a globe and not the mushed parabola of today , and it is possible that an original/original may have had the second filament turned at 90 degrees. (The old artist sketch thing in an era Mazda catalog shows it that way for the Mazda but I don't know as I have never seen one of the original issue dual filament lamps.)
Not to confuse, but what I'm saying is that if you can find a lamp actually stamped (say) 1000 (and not someone determining an anonymous unmarked base was a 1000), then it would have to conform as that was the reason they went to a national lamp number registration/issue system in the first place. It would not matter if the filament was arched as the LCL would be the same, the glass shape change may or may not make an ever so slight change (light bends as it goes through curved glass) and although they really could not test CP, probably be close enough.
Since the LCL of the magneto lamps is in fact 1.250"...and I believe the socket location and that the parabolic reflector was the same place, then the LCL for the primary filament on the above numbers by default has to be 1.250"
Another reference that I have says that the 1000 lamp 'should' be rated at 6.2 volts (the rating gets tricky and is important to a point as there is no flat out 6 volt lamp system as such...the lamps are rated from 5.8 to 7.2 as to nameplate rating and every technical point changes by some mighty weird formula based on the difference in rated volts v. actual volts supplied for use ON 6V systems...
At 6.2 volt rated, the #1000 should draw 24 watts to be a true #1000 per the spec sheet. The filament resistance should then be 1.6 ohms.
The T vendors of today don't help themselves with these lamps...they are either buying lamps from Taiwan that never had lamp numbers on the bases to begin with, or...they were painted numbers and someone lacquer thinners' them off. It would be nice if they put the bulb standard number on them. (I went back and forth last summer for months with one T vendor who claimed he supplied a 6V lamp on 'something' that I bought from him. It wasn't, it was a 12 V lamp but unmarked and therefore barely lit! He was adamant he was right (you guys and gals already guessed the vendor, eh? ) and I was equally adamant he was not! I had a correct lamp in my lamp box and changed it myself but I would call him every week or so to harass him that he should really look into it deeper as others will think they have a bad ground or something when in fact he supplied 12V lamps in the first place! He was nice...each harassing call I made, he sent me replacement lamps as a thank you gift...I now have a whole box of this lamp, all 12V, so I stopped harassing him as I had no use for 12V lamps at all...
Bill Robinson and I have done some work in this area. I talked to Bob, the maker of the headlight sockets to see if those could be changed to correct the filament orientation, tooling cost would be too high, and his are made correctly to original Ford orientation. He also stated that the chance of getting bulbs corrected was slim to none. So, we devised a technique to remove the sleeve in the headlight and change the slot orientation. Then I had a fixture fabricated to correctly drill a second hole in the headlight bucket (same location as a 1915 magneto headlight). I then use a screw and nut to fill the now unused hole.
To move the sleeve, take a spring bushing driver and push the sleeve from the front to the back about 1/4 inch. This frees the sleeve from the retaining system. Rotate slightly then extract the sleeve from the front. Using the fixture, drill the second hole. Apply a bearing an sleeve retaining compound (I use loctite) and insert the sleeve to align with the new hole. Let the sleeve set for a couple hours, then assemble the headlight. Don't forget to adjust focus.
George, the only thing right about these repro bulbs is that each filament draws 25 watts@ 6.2v as to your specifications for a #1000 bulb. I guess they should be labeled 32/32 cp. Maybe I can convince Don to at least list them as such.
I am going to wade in on this discussion only to offer encouragement and not much helpful data. I used to go to the Henry Ford Museum and research a lot of time with Bruce McCalley. We would meet there. In the later visits I wasn't looking for anything in particular but things to perhaps write about that might be interesting. I decided to write an article on Headlight lamps and their history during the Ford model T era only. I began and it got to be a huge huge project and I decided it was beyond one simple visit. It started out kind of simple but Ford ran into a buzz saw in that as the Headlight technology emerged the various states began to write their own specifications to not "blind" the oncoming horse and wagon or other cars. Ford added a letter to a factory number as they revised it but also in the absence of specifications yet they added a different letter of the alphabet for different sources since they then could keep them separate. The file on the headlight bulb began to grow through the years and by end of production it almost looked like Ford was going to need a different bulb for every state in the union. I closed the book on any research and decided it was not a simple research but was a project in itself just to figure out what changed and when. I gave up on doing it myself but its a real can of worms to try and sort out from the file but probably IS doable if someone wants to devote enough time to it.
I just also wanted to mention that George has it right with regard to bulb details. The "weird formula" that he alluded to has to do with the fact that tungsten filaments have a very narrow voltage range over which they have anything like a constant current draw, constant brightness, or constant life expectancy. The Formula for life expectancy change is Design Voltage divided by Actual Voltage applied raised to the 12th power and then the result of that multiplied by the design voltage life rating. It turns out that if you then run a 12V bulb at 6V you will then get 12/6=2 and 2 raised to the 12th power is 4096. You will multiply the bulb life by a factor of 4096 by operating it at half voltage and as George points out you must read very carefully as to what the Design Voltage actually is/was in order to know what is going on. Conversely if you operate a 6V bulb from 12V you will get 1/4096 of its expected life at 6V. Yep it is almost a flash bulb. Even within a single bulb that might have 2 filaments, the design voltage for one filament may be different than for the other. This is common with brake light and running light combo bulbs.
The point is that there is NO single bulb that was used for Model T's or anything like that. There were lots of differences and Ford had to know which state of the union the car was going to in order to comply and then as now the states with the most regulations in general were the problem states.
I have some original Ford bulbs and some Mazdas. I'll have to take pictures and post them.
It would be nice to have a "true" 32/50 cp bulb. It would also be great if a sealed beam headlight were available as it is for the "A". Also, does anyone know the ACTUAL amperage draw and cp rating of each filament in the halogen replacement?
I'm using 1158's in my '25 and like them. If you use a 32-50, the generator can't keep up! I think the original manufacturer of them was Tung-Sol.
Here are some shots of what I believe may be original bulbs. They were in my 26 Tudor that is a very original low usage car.
Very Hard to see on the above bulb but on the top of the glass "DOT 32 & 32" is etched into the glass. So this is double filament but the same candle power on each. There is no manufacturer on the bulb.
Here are a few bulbs:
21-21 CP Mazda 6-8V
32-32 CP Westinghouse 6-8V
32-32 CP Tung Sol (newer style) 6-8V
Here's a chart I found in an old Sunray Lighting catalog. It shows graphically how the Average Life drops off when you get above the Design Volts.
My hoard of GE and Westinghouse No.1000, 32/32CP lamps are marked "6-8 Volts".
I shall presume the actual Design Voltage is 7.0.
This would mean that at 6.0 volts, they only give about 16CP each.
And I hope they never see 8 volts as that would severely eat into the lifespan.
I have an original Ford script bulb around here somewhere, but I can't find it. Ford didn't put the bulb number on it. When I find it, I'll get a photo of it.
Thanks Larry. If you find it, I look forward to seeing it. Jim Patrick