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Woodworking Math

Lathe speed by blank diameter

Lathe speed for a 3 in blank

Spindle speed for a blank 3 in (76 mm) across, for roughing, general cutting and finishing, from the speed charts in lathe makers’ manuals. Start slower for an out-of-balance blank, and your own lathe’s chart is the authority for your lathe.

Speed by operation

OperationRPMJETGrizzlyDeltaBasis
Roughing760600760600–1,000

Median of 3 sources

General cutting1,5001,5001,6001,000–2,000

Median of 3 sources

Finishing2,3002,3002,4801,500–2,000

Median of 3 sources

Each maker’s figure for the band that holds 3 in, as its manual prints it; where 3 in sits on the edge of two bands the slower band is read. A dash means that chart stops short of this size. At the general-cutting speed the rim of the blank travels 1,178 ft/min (π × 3 × 1,500 ÷ 12).

Sources: JET, JWL-1442VS wood lathe operating instructions: speed by diameter of work (p. 4); Grizzly, G0632 16" × 42" variable speed wood lathe manual: speed recommendations (Figure 28); Delta, 46-700 wood lathe manual: recommended spindle speeds.

The diameter × RPM rule of thumb

Blank diameter in inches × RPM of about 6,000 for roughing, up to about 9,000 for finishing. For a 3 in blank that is about 2,000 RPM roughing (6,000 ÷ 3) up to about 3,000 RPM finishing (9,000 ÷ 3). It is a turners’ rule of thumb, not a measurement, so it sits beside the makers’ figures rather than changing them.

Traditional rule, stated by Turn a Wood Bowl and Simple Woodturning Tools

Speed and safety

  • Turn larger and out-of-balance work slower: speed drops as the diameter grows, and an unbalanced blank wants a lower speed still.

    3 sources agree , sources [1, 2, 3]

  • Delta: change speed only while the lathe is running.

    One source: Delta, the maker of that lathe , sources [4]

  • OSHA requires a wood lathe’s cutting heads to be covered as completely as possible by hoods or shields (1910.213(o)(2)).

    One source: OSHA, the federal standard , sources [5]

Sources

  1. JET, JWL-1442VS wood lathe operating instructions: speed by diameter of work (p. 4), read 2026-11-07
  2. Laguna Tools, Revo 24|36 lathe manual (troubleshooting: an unbalanced job wants a slower speed), read 2026-11-07
  3. Woodcraft, "Expert Answers: Safe Turning Speeds" (Mike Kehs, Woodcraft Magazine), read 2026-11-07
  4. Delta, 46-700 wood lathe manual: recommended spindle speeds, read 2026-11-07
  5. OSHA, 29 CFR 1910.213, Woodworking machinery requirements, read 2026-11-07