3308 Headstock and Motor Unit with ER-16 Spindle Nose


The 3308 would replace the standard headstock, motor and speed control assembly that come on Sherline machines.

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Product Description

ER-16 Spindle Available

Note that the headstock, DC motor and speed control can also be ordered with an ER-16 collet spindle nose in place of the standard Sherline #1 Morse internal taper and 3/4-16 thread on the nose for those who prefer to use ER-16 collets. Sherline does not supply the collets or the nut, but they are available through MSC and other tool suppliers. Keep in mind that if the ER-16 nose is ordered, no Sherline accessories that use a #1 Morse taper or 3/4-16 thread will work on this spindle.

To power, and control the motor a more sophisticated speed control unit is required. This unit accepts any incoming AC current from 100 VAC to 240 VAC, 50 or 60 Hz and automatically outputs 90V DC to the motor, so this unit can be used anywhere in the world without a transformer. All you need is the correct wall plug or converter. Once the on/off switch is switched to the “ON” position, a speed control knob is used to vary the speed over the entire range. With the pulley in the “normal” position, the speed range is about 70 to 2800 RPM. In the “high torque” position the maximum speed is cut in half but torque at any given speed is much greater.

This unit can be purchased to replace an existing AC/DC motor on an older Sherline machine, to turn a mill XYZ base into a complete mill so that you don’t have to swap power units back and forth from the lathe, or as a stand-alone unit for custom tooling designs. This very compact and well-engineered unit costs far less than other DC units of similar power offered in major industrial tool supply catalogs.

Other Purchasing Options:

3306 Headstock and Motor Unit (2,800 RPM)
3307 Headstock and Motor Unit (10,000 RPM)

The improper use of machine tools and their accessories can result in serious injury. Before using this tool, thoroughly read the instructions and make sure you understand its proper and safe use.


Always wear safety glasses when operating machine tools.

Download PDF 3306 Instructions

Instructions PDF Download

Type of enclosure Totally enclosed, non-vented
Duty rating Continuous–10 oz. in. at 6100 rpm, .85 amperes; Intermittent–30 oz. in. at 5500 rpm, 1.75 amperes (5 minutes on / 15 minutes off)
Output horsepower .06 KW (60 W) at 10 oz. in. / 6100 rpm
AC voltage (input) Normally 115 VAC, 60 Hz, Single Phase to rectifier (Sherline electronic speed control converts any input from 100 VAC to 240 VAC, 50-60 Hz.)
DC voltage 90V DC to motor (60 Hz)
Speed in rpm 6100 rpm continuous
Class of insulation Class A, 105° (C.) insulation system
Normal full load current .85 amperes
Starting current 17 amperes instantaneous starting current (<100 milliamperes). This is also stall current in True RMS
Max current at time of changeover from lower speed to higher speed Depends on load
Type of motor 3.00 inch (outer diameter) sub-fractional horsepower brush-type permanent magnet motor
Temperature rise at ambient 50° C. Less than or equal to 45° C.
Motor frame size 3 inches
End use of motor Drive unit for lathe or mill
30111 ER-16 Headstock Assembly
33050 DC Motor & Speed Control Assembly
40020 Motor Bracket
40040 Drive Belt