Just for the sake of fun I tried to make my own glow adapter. First of all I didn't have 14mm 1.25 die. But I figured out, that metric thread 1.25mm is close enough to imperial 20tpi. This thread I could set on my mini lathe. I never made thread on lathe before, but that's the chalange.

I bought one 3/4 machine screw for material (nice piece of steel rod). Few hours of fun, and here is the result. It weights 15 grams. The glowplug is sticking out enough for any king of clamp. I didn't bother to cut hex for the wrench, as I can use pliers - it is one time deal anyway as I would change only glow plug, not the adapter.