RE: SYSSA 30CC GAS MADE IN USA
Actually rigid tapping is in referrence to the tool holder type. Regular tapping on a machining center uses a tap holder that has compression and extension spring to accomodate for feed errors in the Z axis.Rigid tapping uses a solid body tool holder that does not let the tap "float".
Solid tapping requires closer synchronization of the spindle and Z axis than normal tapping. Its an standard or an option on more precise machining centers.
Mentioning rigid tapping in the picture does suggestion the machining is being done on machine made to higher standards.
Thread forming in aluminum is superior to cut threads as they are actually cold forged they are significantly stronger.