663 Hea vy Duty Micrometer Heads 0-1"/0-25MM The 663 is similar to the 263 but features heavy duty construction with a larger diameter spindle, clamping surface and thimble. • Available with lock nut and the combination ratchet and speeder for uniform pressure and quicker adjustment, or a plain micrometer head with lock nut only • Ring-type lock nut for quick and sure locking Micrometer Heads 663 Heavy Duty Micrometer Heads (0-1" Range) Cat. No. EDP Graduation 663L 52772 .001" 663RL 52773 T663L 52777 .0001" T663RL 52778 663M Heavy Duty Micrometer Heads (0-25mm Range) Cat. No. EDP Graduation 663MRL 52774 0.01mm V663MRL 64342 0.001mm 4-1/2" (114) 2-1/2" (63.5) 7/8" (22) .5624" .5616" (14.286) (14.272) 25/32" (20) .300" (7.62) 1-1/4" (32) 3/4" (19) 663L (0-1") and 663ML (0-25mm) dimensions 5-1/16" (129) 2-7/16" (16) 53/64" (21) 25/32" (20) 1-1/4" (32) .300" (7.62) 9/16" (14) 5/8" (16) .5624" .5619" (14.286) (14.272) 663RL (0-1") and 663MRL (0-25mm) dimensions 663RL 70 M icrometers