Carton 100mm f/13 "MD" OTA Construction - Billet of Aluminum for Rear Cell (Milling Started)
 

Brian Choin begins milling of the 6" OD x 3" billet of T-6061 aluminum fabricating the rear objective cell on his lathe. (Click to see an enlarged image.)

 
Milling has started on the solid 6" OD x 3" L billet of T-6061 aluminum, which will form the rear cell for the Carton 100mm f/13 objective. Here a carbide tipped cutter is meticulously plunged into the center of the billet by Brian Choin and gradually and precisely maneuvered to removed specific amounts of material from the billet as it forms the rear cell. The three 120-degree angled holes were tapped and used for holding the billet to the chuck securely when milling from the opposite side of the piece.