Gang Tumbler for small parts.
With this ganged tumbler you can work four different materials at once - or charge the four containers with various types of burnishing or polishing abrasives to take care simultaneously of several stages in the treatment of a single material. Very practical.
Three pages ( 2 sheets - front on first, front & back on other sheet ) B & W photos, illustrations, expanded views and instructional narrative.
My plans are from original source materials such as books, magazines and other publications and the pages are carefully removed.