u/Aggressive_Fan_9646

I purchased an oil lamp electric conversion burner from amazon. The screw on collar is ever so smaller than the threaded neck that it will not screw on. I purchased another screw on collar from Antique Lamp & supply, and it too is too small. I was told the now manufactured collars will not fit the older lamps. Strange. Where can I find replacement collar for #2 burner that will fit the older size lamps?