Machine Shop Safety

A campus machine shop

Photo credit: Princeton University School of Architecture

Machine shops present unique hazards distinct from those in laboratories or other work environments. Princeton University has very specific requirements for work in machine shops on campus. For information on the University’s machine shop program, please click on the following links:

Undergraduate Machine Shop Policy

The Environmental Safety and Risk Management (ESRM) Committee adopted this Policy on Undergraduate Machine Shop 12-20-2011.pdf. This policy applies to all academic departments that have designated shop areas.

Machine Shop Training

Work in machine shops requires both general training on machine shop policies and hands-on training on each specialized piece of equipment in departmental shops. All machine shop workers must complete an 11-minute online orientation prior to attending hands-on training. Shop supervisors are responsible for ensuring that undergraduate students have attended and successfully completed Princeton-specific machine shop and safety training for each type of machine they are expected to operate and that they are conducting work commensurate with their skill and training.

Machine Shop Supervision

Undergraduate students are prohibited from operating machines or performing any other activities in a University machine shop unless supervised by the shop manager or a designated monitor. Working alone by undergraduates is strictly prohibited. All others are strongly discouraged from working alone.

Shop supervisors and monitors may prohibit shop access or machinery use by an individual or group for non-compliance with shop safety rules. Serious violations will be referred to the sponsoring faculty member and academic department manager or the Dean of Undergraduate Students as appropriate.

Machine Shop Rules

The following rules are applicable to all academic machine shops on campus:

  • Shop Hours: Work performed by undergraduates in machine shops is permitted only during designated times established by the shop supervisor or monitor but may not occur between the hours of 2:00 AM and 8:00 AM.
  • Shop Authority: Shop supervisors and monitors may prohibit shop access or machinery use for any reason
  • Training: No power machinery may be used without documented completion of safety training
  • Supervision: Undergraduates may not work without the supervision of a shop supervisor or monitor. All others are strongly discouraged from working alone
  • Safety Glasses: Safety glasses (meeting ANSI Z87.1-1989 or later) are required when equipment is in use. Additional protective equipment may be required for certain operations.
  • Loose clothing, hair and jewelry: No loose clothing may be worn in the shop - including ties, scarves and loose sleeves. Long hair must be contained and pulled back tightly. Long beards must also be contained. All jewelry, including rings, necklaces, bracelets and watches must be removed when using power equipment.
  • Attire: No open-toed shoes may be worn. Long pants are strongly encouraged.
  • Malfunctioning Equipment: Report all damaged or malfunctioning equipment to the shop supervisor or monitor. DO NOT use malfunctioning equipment.
  • Eating and Drinking: Food and drinks are prohibited.
  • Compressed Air: Compressed air MAY NOT be used for cleaning skin or clothing. End nozzle pressure of compressed air used for cleaning equipment may not exceed 30 psi.
  • Emergency access: Keep aisles, exits and access to emergency equipment clear
  • Housekeeping: Clean up before and after each machine use.
  • Report Issues: Immediately report all problems or concerns to the shop supervisor or monitor
  • Guards: All guards and shields must remain in place during machine operation.

The Princeton University Shop Rules poster must be prominently displayed in all campus shops. Posters can be printed by clicking on the link to the right or can be requested from EHS by calling 609-258-5294.

SawStop Table Saws

SawStop Table Saw

The University requires the use of SawStop technology on all tables saw purchases and no table saw may be placed into service if it is not equipped with SawStop.  This requirement extends to saws currently in storage or whenever a table saw is transferred from one shop or department to another.

If you discover that your group or shop owns a table saw that is not equipped with SawStop technology, please remove it from service immediately and contact Kelly States at 258-2648. 

Any brake activation involving a SawStop device that is the result of a person coming into contact with the blade must be reported to EHS and the injured person (no matter how minor the injury) must be treated at University Health Services.  In all such cases, the braking device must be retained and provided to EHS for analysis by SawStop. 

You can learn more about SawStop at