Black Anodized Optical Lens Barrel in 6061/7075, Turn-Milled Stepped Bore, Matte Black Finish

About This Part

This barrel holds a stack of lenses in alignment, which means every feature serves the optical axis. The internal bore steps down through several H6/H7 seats at +0.012/0 mm, each one landing a lens or spacer at its designed axial position, and each seat face running square to the axis so the lens does not tilt. Misalign a seat and the optics go soft; so the whole internal profile is bored in one chucking on a turn-mill center, keeping seat-to-seat coaxiality within 0.01 mm and the thread array within 0.015 mm.

The outside carries its own function: fine straight threads for focus and lens retaining rings, cut to 6H/6g optic grade so they turn smoothly without play, seal grooves, and diameter steps where mating hardware mounts. End faces carry arrays of small tapped holes for front hardware, and a precision axial slot machined down the sidewall gives access for focus adjustment or an aperture stop.

Thin walls and deep slots make the barrel delicate to machine. Cutting pressure on a thin section moves the part, and a moved part reads as out-of-round seats. The route stages roughing and finishing with stress relief between, uses sharp tooling with light finishing passes, and clamps on generous soft jaws so the final cuts come off a part that has already relaxed.

Finishing is matte black anodize, and it has two jobs here. Outside it is a hard, scratch resistant surface. Inside it is optical: the matte black, non reflective bore wall absorbs stray light that would otherwise scatter between lens elements. Film thickness is controlled so the precision seats and threads stay within their bands, and finished barrels are gauged with thread plug and ring gauges, bored seats checked with bore gauges, and the whole geometry re-verified on the CMM.