ABSTRACT
REFERENCE: MIL-G-45930(WC) 19 July 1974; PARA. 3,6.1.
3.6.1. DRIVER. The driver shall be a hand-held electric - powered rotary tool for driving the grinding wheels.
3.6.1.1. SPINDLE DRIVE. The spindle drive shall transmit the power from the motor to the grinding wheels to
perform the valve seat grinding requirements as specified below in Table I:
TABLE I.
Requirements for both Type I and Type II grinding kits: Valve seat outside diameter, range, in inches, 1-3;
Spindle speed, RPM, minimum (no load) 8,000; Motor, Horsepower, minimum 1/3. Rated torque range
foot pounds 0.3 - 0.5.
The drive end of the spindle drive shall incorporate provisions for connecting the grinding wheel holder specified in 3.6.3.
The connection shall provide a positive drive fitting between the wheel holder and the spindle without slippage, looseness,
and detrimental vibration during operation of the driver. The drive spindle for the type I grinding kit shall effect an includ ed
angle of 105 to 150 degrees with the center line of the drive spindle and the center line of the armature shaft. If a straight
drive unit is furnished, an angle attachment shall be provided. The drive spindle for the type II grinding kit shall be at an
angle to accommodate grinding seats as shown in Figure 1.
3.6.1.2 HANDLE. The driver shall be fitted with a pistol-grip, planer, D , or straight-type handle affording the
operator a full hand grip. The handle shall permit the operator (one man) to position and control the driver during the
grinding operation.
3.6.1.3 DRIVE MOTOR. The drive motor shall be of the universal type, intermittent duty, in conformance with CC-
M-636. The horsepower and the torque produced by the driver spindle shall be as specified in Table 1. Unless otherwise
specified (see 6.2.1), the motor shall operate from a nominal power source of 115 volts, 60 Hz, single phase, and 115 volts
direct current (dc).
3.6.1.4 SWITCH. The motor shall be controlled by a trigger or button type switch of quick break design. Current
rating of the switch shall be not less than the full load current rating of the motor. The switch shall not be equipped with a
mechanism for locking in the on position. Switches shall conform to the requirements of UL No. 45.
3.6.1.5 POWER CORD. The motor shall be furnished with not less than 15 feet of flexible oil resistant, water
resistant, three-conductor cord in accordance with UL NO. 73. The ground conductor shall be securely connected to
provide a common ground with the exposed parts of the grinder frame. The ground connection or connections shall be
made on the inside of the grinder frame. The size of the conductor shall be determined from the full load ampere rating of
the motor and shall conform to NFPA Standard NO. 70. The three-wire grounding plug shall be of the cord grip design
and be in accordance with style D of W-C-596. A mating three-to-two-wire adapter with a grounding wire shall be
furnished for use with a two-wire outlet.
3.6.1.6 BEARINGS. Bearings shall be ball or roller type of suitable design, housed to prevent leakage of lubricant
and entrance of dirt and dust. The bearings shall be lubricated sealed-for-life type or shall be provided with means for
proper lubricant application.
14
