Class Code 3632: Machine Shop Operations — CA Workers Comp Guide

What Class Code 3632 Covers

Class code 3632 encompasses machine shops where employees use metal-cutting and shaping equipment to produce precision parts and components. This includes CNC (Computer Numerical Control) machining centers and turning centers, conventional manual lathes and mills, drill presses and boring machines, surface and cylindrical grinders, EDM (electrical discharge machining) equipment, and broaching and honing machines.

California has a significant machine shop industry concentrated around aerospace and defense manufacturing (Los Angeles Basin, Orange County), automotive components, and general industrial manufacturing. Job shops producing custom parts for a variety of industries and production shops manufacturing high-volume components for specific industrial clients both fall under 3632.

The classification covers the full production environment: machinists setting up and operating CNC programs, operators running parts on manual machines, deburring technicians removing sharp edges from finished parts, quality control inspectors using precision measurement equipment on the shop floor, and setup machinists programming and optimizing CNC toolpaths. Material handling — moving raw stock and finished parts through the shop — is also covered under 3632 when performed by dedicated material handlers employed by the shop.

Who This Code Applies To

The core 3632 employee population is machinists — skilled workers operating CNC and manual metal-cutting equipment. California machinists may be trained through apprenticeship programs (IAM Machinists Union, for example), community college machining programs, or on-the-job training. Wage levels vary significantly, from entry-level operators at $18-22/hour to experienced CNC programmers and setup machinists earning $35-55/hour.

Shop supervisors and forepersons who spend substantial time on the shop floor are coded 3632. Quality engineers or inspectors who work primarily in a lab or office environment may qualify for office coding. Sales and administrative staff of the machine shop are coded 8810. CAD/CAM programmers who work exclusively at a computer without shop floor time may qualify for 8742 — this is a legitimate payroll split opportunity that many machine shops fail to take advantage of.

WCIRB Advisory Rate and Premium Calculation

At $3.82 per $100, machine shops carry moderate workers comp costs. For a CNC job shop with 18 machinists averaging $52,000 annually:

• Total machinist payroll: $936,000
• Manual premium: ($936,000 ÷ 100) × $3.82 = $35,755
• With 1.00 ex-mod and 1.00 LCM: approximately $35,755
• Plus CA surcharges: approximately $37,007 total

If the same shop has 3 full-time CAD/CAM programmers earning $75,000 each who never enter the shop floor, splitting their $225,000 payroll to code 8742 ($0.33/100) saves approximately $7,852 annually — a worthwhile effort for a $225,000 payroll split. Documenting the split with written job descriptions and time records is essential for the split to survive an audit.

Machine Guarding and Cal/OSHA Requirements

Cal/OSHA’s machine guarding requirements (Title 8 CCR 4000 series) apply comprehensively to machine shop operations. Point-of-operation guarding — preventing employee contact with the cutting zone of lathes, mills, grinders, and drill presses — is the primary compliance area. For CNC machines, this typically means interlocked enclosures that stop machine motion when the door is opened during a cycle.

Lockout/tagout (LOTO) procedures for machine maintenance and setup are another major Cal/OSHA enforcement area in machine shops. Every machine must have a documented energy control procedure; employees performing maintenance must follow LOTO before accessing any machine with stored energy.

Eye and face protection from flying metal chips is mandatory — ANSI-rated safety glasses or goggles for all employees in the chip-generating zone, face shields for grinding operations. Carriers review OSHA 300 logs for eye injury frequency as a key safety metric for machine shop accounts.

Common Misclassification Scenarios

CAD/CAM programmers coded as 3632 when they qualify for 8742. Engineers and programmers who create CNC programs at a computer without entering the shop floor are performing computer/IT work. A documented payroll split supported by job descriptions and time records can capture meaningful premium savings.

Metal fabrication welding coded as 3632. If a machine shop also has significant welding operations — MIG, TIG, or structural welding — that work may belong in a welding fabrication code rather than 3632. Machine shops with substantial welding should discuss proper split coding with their broker.

Sheet metal shops attempting to use 3632. Sheet metal fabrication — working with sheet stock, press brakes, punch presses, and shears — may belong in a sheet metal code rather than 3632, depending on the specific operations and WCIRB classification rules.

Typical Injury Types in Code 3632

Lacerations from metal chips and burrs are the most frequent injury type. Sharp metal chips generated by cutting operations become projectiles; sharp burrs on finished parts cut hands during handling. Most are minor, but chip-in-eye incidents and deep lacerations can be costly claims.

Caught-in injuries from rotating spindles, chucks, and workholding devices are among the most serious injury types in machine shops. An employee’s glove, clothing, or hair caught in a rotating chuck can cause degloving, amputation, or severe crush injuries. This is why OSHA prohibits wearing gloves when operating rotating machinery — a counterintuitive but critical rule.

Eye injuries from metal chips and grinding sparks are a consistent claim source. Despite mandatory eye protection requirements, chip-in-eye incidents remain frequent because employees sometimes remove safety glasses for brief tasks.

Musculoskeletal injuries from prolonged standing at machines, repetitive handling of heavy workpieces, and awkward postures during machine setups generate back, shoulder, and knee claims. Ergonomic anti-fatigue mats, adjustable-height fixtures, and lift assists for heavy parts are key controls.

Underwriting Considerations

Machine shops are generally well-understood by construction and manufacturing underwriters. Key factors include: the type of work (aerospace precision machining has different risk characteristics than job shop general machining), equipment condition and age, machine guarding documentation, OSHA 300 log review, and evidence of LOTO programs. Aerospace and defense contract shops often have ISO 9001 or AS9100 certification — which signals strong process discipline and risk management to underwriters.

Shops with older equipment lacking modern guarding systems present higher underwriting risk. Carriers may require guarding upgrades as a condition of coverage or may price them higher reflecting the hazard. New CNC shops with modern enclosed machining centers have demonstrably better injury records than older shops with open manual lathes and mills.

Carriers Active in Code 3632

Zurich and Travelers have manufacturing specialty units well-suited for machine shops. The Hartford writes manufacturing accounts across California. Liberty Mutual is active for larger machining operations. ICW Group writes machine shops of all sizes across California and is a reliable option for mid-market accounts. For smaller job shops, EMPLOYERS and AmTrust offer accessible programs. Aerospace-focused machine shops may benefit from specialty manufacturing programs through CNA or AIG that understand the unique exposures of defense and aerospace manufacturing.