My great uncle (b. 1886 - d. 1964) worked at Smith & Wesson in Springfield, MA his entire working life. Available Federal census data show the following listed occupations for him, all at S&W:

1910 - Age ~24 yrs - "Toolmaker"
1920 - Age ~34 yrs - "Assistant Foreman"
1930 - Age ~44 yrs - "Mechanic"
1940 - Age ~54 yrs - "Extractor"

Recognizing that not all census data are perfectly true & accurate (or even necessarily meaningful), I'd still like to ask the question: What would the S&W occupation or job description "Extractor" have meant back in 1940?

Any & all help appreciated. I'd really like to solve this family mystery.