We reserve the right to decline responsibility where repairs have been made or attempted by others without factory authorization.

U.S. Electrical Tool Inc. assumes no responsibility for contingent or consequential damage. No other guarantee is authorized.

Refer to the nameplate before connecting the power lines to this machine to insure your electrical service matches that shown on the nameplate.

Remove the spindle nut (71), outer wheel flange (64) and install the grinding wheel properly rated for the RPM shown on the caution plate located on the front of the wheel guard.

The wheel must be set into place, not forced. Use wheel blotters on each side of the wheel, between the grinding wheel and the wheel flanges. These are readily available from your wheel source. Replace the outer wheel flange (64) and spindle nut (71).

Jog the unit to make sure the wheel is rotating correctly. The wheel must run "down" as viewed from the operation's position. If the wheel runs "up," turn off the main power supply and reverse any two of the main power lines.

To reposition the wheel, release the spindle nut (71) one-half turn and rotate the wheel independent of the spindle (66) approximately 10 degrees. Secure the spindle nut and start the machine. Repeat this process until unit is in balance. In most cases, new wheels will have an inscription on the wheel itself indicating "top" or "up." This automatically located the heaviest section of the wheel and compensates for pilot diameter fit.

If a wheel is out of round, it must be "dressed" to a true diameter. Use a fixed dresser mounted on the tool rest (88). If vibration persists, refer to the Trouble Shooting section for corrective procedures.

DO NOT adjust the feed screw adjustment while the machine is not operating.
DO NOT alter the guard as it is an integral parts of the speed control.
DO NOT remove slide stop (102) or bearing housing stop (101).
DO NOT operate machine with the outer wheel flange (64) loose on the spindle.

The feed screw nut (80) is lubricated by means of a grease fitting located 5" below and on the centerline of the feed adjustment (65). Use Chevron Polyurea EP #2 grease.

The thrust bearings (72) require only a few drops of SAE #20 oil periodically.

The slide plate (82) and feed screw (58) should be brushed and cleaned when abrasive grit and metallic dust accumulates on these assemblies. To relubricate, use a dry aerosol lubricant on the exposed surfaces.

Some of the older variable speed sheaves were equipped with an oil reservoir. To fill this reservoir, located on the outboard end of the sheave, rotate the sheave by hand until the oil filler hole is at the top position. Remove the oil filler plug. Rotate the sheave 90° either direction. If oil comes from the hole, replace the plug. If no oil appears, rotate the sheave until the oil hole is at the top position and fill with AGMA #15 oil.

NOTE! Improper oil causes the deterioration of the "O" rings within the unit.

CAUTION! After installation or replacement of any drive component (73, 78 or 79) always check the wheel speed through its entire range. See instructions for checking wheel speed below.

With the spindle in this position, start the machine and use a tachometer to determine the actual spindle RPM. Convert this RPM reading to surface speed with the following formula:
 

 
SFPM = Surface feet per minute
WD = Wheel diameter
RPM = Spindle speed
0.262 = PI divided by 12

Using the initial procedure, take additional tachometer readings in 1" radius increments throughout the spindle adjustment range. The resulting surface speed derived from the formula must not exceed the maximum surface speed shown on the machine caution plate.

Remove the grinding wheel and the old belt (78). Move the wheel head to the extreme rear position. Place new belt (78) over variable speed sheave (73) and the belt changing hook welded to inner rear wall of the base. Move the wheel head forward to seat the belt deep in the groove of the sheave. Reverse the direction of the wheel head and place the belt over the motor pulley (79). Rotate the spindle pulley by hand until the belt is taut.

Reconnect power supply.

CAUTION! It is mandatory that all belt replacements must be exactly the same as originally installed at the factory. All belts have a standard code as to size. Example: 4430V850, the first two digits multiplied by .0625" indicate the top width. The second two digits indicate the included angle of the belt. The remaining numbers indicate the pitch length of the belt. Hence, 4430V850 is 44 x .0625" = 2.750" across the top, with a 30° included angle and a pitch length of 85.0". Various variable speed belts (78) are furnished to cover the range of horsepower requirements.

Using pressure, press out the spindle (66) in either direction. One bearing will remain on the spindle and has to be removed with a bearing puller. The bearing remaining in the spindle housing (70) should be removed by inserting a rod through the opposite end of the bearing housing and pressing against the inner bearing race. Light tapping on the rod will remove the bearing. CAUTION! Excessive hammering on the inner race will result in damage to the bearing. In reassembling, insure that bearings and bearing surfaces are free of any foreign matter. Press one bearing onto the spindle and the other bearing into the spindle housing. Bearings are set by tightening the bearing lock nuts (52, 53). Be sure to install the proper dust cap (56, 57) on the proper side. The dust cap (57) on the wheel side has a longer pilot which locks the outer race of the ball bearing. The other dust cap allows clearance between the bearing and the dust cap.

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To determine the source of vibration, remove the wheel and restart the grinder.

• Vibration due to excessive slide clearance is corrected by adjusting the tapered gib (83) as follows:
• Loosen rear gib adjusting screw lock nut (86) and back off gib adjusting screw (85).
• Tighten front gib adjusting screw (84) until all play is removed between slide (82) and taper gib (83).
• Turn rear adjusting screw (85) until it is firmly seated against taper gib (83) and secure with lock nut (86).
• With the motor running and the wheel removed, turn the ratchet wrench (65) and move the head forward and reverse to determine if the variable speed sheave is functioning. If there is any hesitation, spray the arbor between the flanges with a molybdenum dry lubricant. Do not allow lubricant to get onto the sides of the sheave.
• Check the belt (78) for cuts or dirt accumulation.
• Check both sheaves (73, 79) to see if they are loose on the shafts.
• Check the wheel flanges (61, 64) for nicks or wear.
• Check the foundation bolts and surface upon which the grinder is mounted.

Remount the wheel according to the manufacturer's instructions. Mount with the heavy side (usually indicated by an arrow) down.

• Check companion sheave (79) on the motor to be sure belt in not bottoming.
• Check variable speed sheave (73) to make sure it is operating.
• Replace belt (78) if worn.
• Do not apply belt dressing.

• Remove the feed screw bracket (59) and remove feed screw (58) by turning counter-clockwise.
• Check for dirt accumulation on slide (82), feed screw (58) and feed screw nut (80).