One of the most useful pieces of equipment in the farm shop is the power-driven grinder. It saves the farmer a great deal of time and helps him take care of grinding and sharpening jobs. To get the most out of this useful machine tool, it and its motor must be properly mounted. One way of doing this is to mount both directly to the top of a bench or to a plank, as shown in Figure 1. The plank has the advantage of being portable. It must be 12 in. wide to permit the pulleys to line up, but if one of this width is not at hand, a piece 1% in. thick may be spiked or screwed to the edge making it the desired width. The switch to turn the current on or off should be placed within easy reach of the operator.
The dimensions shown in Figure 1 are for the ^-h.p. motor and farm grinder with 6-in. wheels illustrated in the following pages, but if another grinder or size of motor is used, the dimensions must be changed accordingly.
To transmit the maximum of power, a belt must be kept tight. A method of tightening is to make slotted holes in the platform on which the motor is mounted for the bolts that hold the motor in place. These slotted holes are made at least in. long and wide enough to allow the bolts to slide freely. The holes in the underside of the plank are made large enough for the heads of the bolts to set up into the plank flush with the surface, thus allowing the plank to lie flat on the bench. This would not be necessary if the motor were fastened directly to the top of the bench.
When belting the grinder, slide the motor as near the grinder as the slotted holes will permit. When the belt becomes slack, crowd the motor back into the belt.
An endless, flat automobile-fan belt is best suited for driving the grinder. If a laced belt is used, the metallic-wire belt lacing is preferable to the rawhide thong because it jerks less as it passes over the small pulleys. The farm grinder, shown in Figure 13, comes equipped with a 6-in. wheel, a beveled sickle cone, and a 2^-in. pulley. The motor is 1725 r.p.m. A 3%-in. pulley on the motor drives the grinder 2415 r.p.m., which is a suitable speed for good work. The motor should be of the inclosed type so as to prevent grit from the grinder and iron getting in the motor.
Was this article helpful?