15-06-2023, 12:44 AM
(This post was last modified: 15-06-2023, 12:52 AM by Tony Griffiths.)
On my 1929 Chummy, the 6-volt headlamps have a single contact bulb holder and to fit one of the new high/low beam bullseye bulbs, they needed changing. I bought a pair of new double contact BAY15D type holders from Classiccarleds.co.uk and set about fitting them.
I turned up a bar that was very close fit in the bulb holder and held this in a pair of very soft vice jaws - the bar preventing the bulb holder from being compressed and allowing me to carefully bend back the tabs holding the white "contact unit" (seen in the picture) and extract it. Of course, the unit is not a drop-in fit into the original holder but has to have two opposing bulges very carefully ground off - it's not a soft plastic but surprisingly hard stuff.
Once the side retaining tabs on the original single holder had been bent back it was extracted and the new unit dropped into place.
As sidelights are now hardly ever used, I decided to do away with them and connected the sidelight wire to the dipped contact and the headlamp wire to the main.
A quick juggle of the headlamp swivel bracket to get things lined up and out for a road test. To my surprise, and by good luck, the initial setting proved spot on. The beam - I chose the 3000K warm-white type - is good enough for country lane motoring with the dipped bean perfect - though the main does perhaps lack penetration. On main beam, once over 30 mph, the ammeter showed a positive charge.
Before doing this I'd experimented with a scrap reflector by cutting off the original bulb holder, reaming out the hole and soldering in a new, as-received, twin contact holder. This worked perfectly but, as I was reluctant to alter the original R47 reflector, choose a method that would allow conversion back to standard.
I turned up a bar that was very close fit in the bulb holder and held this in a pair of very soft vice jaws - the bar preventing the bulb holder from being compressed and allowing me to carefully bend back the tabs holding the white "contact unit" (seen in the picture) and extract it. Of course, the unit is not a drop-in fit into the original holder but has to have two opposing bulges very carefully ground off - it's not a soft plastic but surprisingly hard stuff.
Once the side retaining tabs on the original single holder had been bent back it was extracted and the new unit dropped into place.
As sidelights are now hardly ever used, I decided to do away with them and connected the sidelight wire to the dipped contact and the headlamp wire to the main.
A quick juggle of the headlamp swivel bracket to get things lined up and out for a road test. To my surprise, and by good luck, the initial setting proved spot on. The beam - I chose the 3000K warm-white type - is good enough for country lane motoring with the dipped bean perfect - though the main does perhaps lack penetration. On main beam, once over 30 mph, the ammeter showed a positive charge.
Before doing this I'd experimented with a scrap reflector by cutting off the original bulb holder, reaming out the hole and soldering in a new, as-received, twin contact holder. This worked perfectly but, as I was reluctant to alter the original R47 reflector, choose a method that would allow conversion back to standard.