Does anyone know of a company that makes a 6V halogen bulb with a screw base?
I want to replace the incadescent bulb in a vintage light.

I think it will be a lot easier to find a screw base led bulb.

I don't know who makes them but here's a company that sells them.

https://www.sjscycles.co.uk/currency/...-Halogen-3.htm

OEG Products

I have an older Union headlight (battery powered) that takes a 6V halogen. Glad to see the links above! However, I did, at one point, try an LED. The only down side is some higher power LEDs get hot. My Union headlight doesn't have any vents or heat sinks and I ended up melting the LED bulb on my 3rd ride to work.

I'm sure you already know this...but be careful not to touch the glass halogen bulb with your bare hands when installing it. The oils from your fingers may cause the bulb to burn out. I also did that on a $7 replacement halogen bulb for my Union. Some bulbs are made better than others.

Jerry H

You can rub the oil off with denatured alcohol. A left-over smudge may lead to enough temperature gradient across the bulb's glass, to crack the glass.

your behind the times with a halogen bulb system. i use a B&M Lumotec IQ Fly led front light with standlight & a B&M lumotec led rear light. these lights are way brighter than bulb types, & get bright at walking speed. i use a hub dynamo also. these lights stay bright when stopped for about 5 minutes & charge up when riding. check out these beam pics from peter white cycles: https://www.peterwhitecycles.com/headlights.asp

compare the led systems to halogen, not even close...