Dan,
Gotcha. Phew! I was just getting confused. It sounded like you were saying he needed a new cone with wider tip even if he used the same lens but with a longer tube or barrel, but you were really referring to the use of a longer lens requiring a different cone/wider tip.
Thanks!!!!!
Dave
900x600 80watt EFR Tube laser from Liaocheng Ray Fine Tech LTD. Also a 900x600 2.5kw spindle CNC from Ray Fine. And my main tool, a well used and loved Jet 1642 Woodlathe with an outboard toolrest that helps me work from 36 inch diameters down to reallllllly tiny stuff.