Bench Grinder
I bought a 1960s Craftsman bench grinder at an auction for $20. I've heard Craftsman motors from this time period were some of the best they've made. I had no idea if it worked, but it spun nicely by hand. When I got it home and plugged it in, it ran wonderfully. The ball bearings were smooth and there was absolutely no vibration. It only had one tool rest, spark arrestor and end cap so I needed to make these items. The tool rests that come on these consumer grade grinders are pretty pathetic. They only have about 2 square inches of surface area and the adjustment is pretty limited, so I decided to make new rests for both sides.
The spark arrestor and end cap were easy to make. I traced the existing ones on a piece of sheet metal and cut them out. I drilled the holes in the end cap with a cordless drill and used the mill for the slot in the spark arrestor.
The tool rests took a bit more work. The tops are 1/4" plate that I squared up on the mill. The pivot piece is 1/2" plate bolted to the top with flat head, countersunk screws and a 1/4" clearance hole for the pivot. The arms are made from 3/16" flat bar with slots milled in them for adjustment. One arm has a 1/4" clearance slot and the other has a 3/8" slot to accommodate the shoulder nut. I made the nut from 1/2" hex 12L14. I used hex just for the look. I don't need to use a wrench on it since the slot in the arm keeps it from rotating. These new rests have 12 square inches of surface and have a large range of height and angle adjustment.
The grinder has 1/2" shafts and the new wheels have 1" holes. They came with a series of plastic bushings to reduce the hole size, but they had a sloppy fit. The wheels didn't track straight and didn't spin concentric with the shaft. I made some simple bushings (not shown) from 1" aluminum bar. I indicated the bar in the 4 jaw chuck and drilled a clearance hole for the shaft so it was concentric.
The spark arrestor and end cap were easy to make. I traced the existing ones on a piece of sheet metal and cut them out. I drilled the holes in the end cap with a cordless drill and used the mill for the slot in the spark arrestor.
The tool rests took a bit more work. The tops are 1/4" plate that I squared up on the mill. The pivot piece is 1/2" plate bolted to the top with flat head, countersunk screws and a 1/4" clearance hole for the pivot. The arms are made from 3/16" flat bar with slots milled in them for adjustment. One arm has a 1/4" clearance slot and the other has a 3/8" slot to accommodate the shoulder nut. I made the nut from 1/2" hex 12L14. I used hex just for the look. I don't need to use a wrench on it since the slot in the arm keeps it from rotating. These new rests have 12 square inches of surface and have a large range of height and angle adjustment.
The grinder has 1/2" shafts and the new wheels have 1" holes. They came with a series of plastic bushings to reduce the hole size, but they had a sloppy fit. The wheels didn't track straight and didn't spin concentric with the shaft. I made some simple bushings (not shown) from 1" aluminum bar. I indicated the bar in the 4 jaw chuck and drilled a clearance hole for the shaft so it was concentric.