Section 179 is a provision in the U.S. tax code that allows businesses to expense the cost of qualifying equipment in the same tax year it is placed in service, rather than depreciating that cost over several years. For buyers of used CNC machines, this rule can be particularly valuable because pre-owned equipment generally qualifies as long as it is used for business purposes more than 50% of the time and is placed in service by year-end.
In practical terms, Section 179 enables machine shops, fabrication facilities, and contract manufacturers to treat a used CNC lathe, mill, turning center, or machining center as an immediate business expense. This can reduce taxable income for the year the machine goes into production, which may support improved cash flow for tooling, maintenance, workforce expansion, or additional machine purchases.
For 2025, the Section 179 deduction limit is $2,500,000, with a phase-out threshold beginning at $4,000,000 in qualifying equipment purchases. These limits make the provision accessible to small and mid-sized shops that invest in used machining equipment throughout the year. Because eligibility depends on placed-in-service dates, documentation, and overall equipment spending, many CNC buyers coordinate their machine purchases with year-end tax planning.
Most types of used CNC machinery may qualify, including mills, lathes, horizontal machining centers, vertical machining centers, laser systems, and certain shop support equipment. Buyers should confirm with a tax professional how Section 179 interacts with bonus depreciation and standard depreciation to determine the most efficient approach for their specific situation.
