Perfect Circle Piston Rings - How They're Made (1932, Silent) | 16mm Film Scan

Segment of silent film (soundtrack added) produced by/for the Perfect Circle Piston Ring company, circa 1932. The film showcases how the rings are manufactured at the foundry, being the first piston rings with "individual casting," specifically the "85 Oil‑Regulating ring with Compensating Channel." I believe this is from a lost 5‑part industrial film series on piston rings titled "Endless Channels," however that film apparently had a soundtrack and this film had none, it was double perf. Really not sure what the story is here—maybe there was a sound‑synchronized record version? Perhaps it’s a work/editing print that made it to the public? Suppose we’ll never know. Pretty early days for sound‑on‑film anyway.