An asymmetric thread impact drivable screw and clip for use with a power impact device for penetrating wood fibers while minimizing cut fibers. The freeze plate includes a freeze plate surface, a sealed chamber adjacent the freeze plate surface, one or more refrigerant lines in said sealed chamber, and a fluid in said sealed chamber in thermal contact with the freeze plate surface and the one or more refrigerant lines. A set of kinoforms diffract the angularly modulated beam into a bundle of diffracted beams. The ring balancer facilitates automatic lamp striking and the lamps can be advantageously driven by a common voltage source. After ashing, the lines will have been reduced in width by the amount necessary to obtain the correct CD.