Expert Answers: Safe Turning Speeds

Diameter Suggested Turning Speed (RPM)
Up to 4" 3500
4-10" 1800-3500
10-16" 1000-1800
16-24" 400-1000

Q I enjoyed the article in issue #88 about turning a table lamp, and it got me wondering about lathe speeds. Can you give me some general guidelines as to appropriate rpm when turning? For example, should large-diameter work always be turned more slowly? And does the rpm depend on the type of wood and its density?
—Matt Beyerson, Albuquerque, New Mexico

A For the cleanest, most efficient turning, you want to spin the work as fast as possible while still maintaining stability for safe turning. An imbalanced blank can be difficult to cut. (In extreme cases, it can even make your lathe gallop across the floor.) As you surmise, the right speed is actually a range that depends on a few variables, the most relevant of which is the diameter of the turning blank. Basically, the smaller the diameter, the faster you can spin the wood, as shown in the chart above.

Of course these speed suggestions don’t take into account variables such as lopsided wood density or voids, which can introduce imbalance into a piece. So can an asymmetrically sawn blank, which is why it’s always wise to begin at low rpm regardless of the diameter.

Ramp up the speed from there as you shape the piece into balanced concentricity. (This approach is also prudent if you’re not entirely certain about the security of the blank-to-lathe attachment.) And don’t forget to check the lathe speed setting before you turn the machine on!

Changing speed and gauging specific rpm is easy using EVS (Electronic Variable Speed) controls, found on many modern lathes. Specific rpm may be harder to gauge on multi-pulley lathes that simply offer a variety of speed setting. Every turner has a particular comfort level regarding speed. Heed yours. Regardless of any recommended “optimum” rpm, if it makes you uncomfortable or tense, slow it down.
—Answered by professional turner Mike Kehs 

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