Disk Sander

Build this disk sander with parts that are probably sitting around your shop gathering dust. All you need is a 1/4 hp or larger 1750 RPM electric motor, a v-pulley, switch, electrical cord and scraps of wood.

Assembly

Step 1

Measure and make a note of the height of the center of the motor shaft.
Step 2

Mount the motor on a base of 3/4" thick plywood that is at least 14" wide and 10" deep. The shaft must protrude over the front edge as shown.

Step 3

Cut two blocks to mount table, distance "X" is the height of the motorshaft center minus thickness of table material.

Trim two of the corners out as shown.

Step 4

Cut a 9 1/8" dia. circle from 3/4" plywood. Drill three holes 1/4" in diameter in a V-pulley, center pulley on the face of the disk and mark position of holes. With a 5/8" spade or forstner bit drill 1/8" deep inserts for carriage bolt heads. Drill 1/4" holes through disk and fasten pulley to it with carriage bolts. Install disk and pulley assembly on to motor shaft.

Step 5

Fasten the two table brackets to the base, with two screws in each, allowing a minimum of 1/4" clearance for sanding disk.

Step 6

Fasten two strips beneath base to allow clearance for disk.

Fasten 3/4" thick 6" X 14" table to brackets with 1/4" carrage bolts, sink the heads using a 5/8" spade or forstner bit.

Step 7

Connect the switch and cord to motor.

Step 8

True the disk by wrapping sandpaper on a block of wood, with the block sitting on the table hold it against the edges and face of the spinning disk. Sand edges until diameter measures 9".

Step 9

Remove the table, then the disk, glue 9" X 11" sandpaper to disk with white glue. Clamp as shown using scrap piece of plywood, trim sandpaper when dry. When sandpaper is worn out simply glue another sheet on top of it. Eventually you will have to strip all the layers off and start over.

Another alternative is to use 9" adhesive backed sanding disks.

sanding sisk


Circle Sanding Jig

This is a handy jig to smooth the edges of rough cut circles if they have an axle hole in the center.

Assemble the pieces as shown, glue the top strip as well as fastening it with screws, put a screw in the end of the sliding piece for a stop, without this sawdust may get between the two parts and affect the setting.

To set the jig, clamp it to the sander table, measuring from the face of the disk to the center of the dowel pin for radius of the circle. Slide the circle in and rotate it against sanding disk.

Put an Old Table Saw to Use

saw with sanding disk

A table saw can also be converted to a disk sander, this will give you the added advantage of being able to tilt the disk and make use of the miter gauge and slots in the table. Many people make use of their old table saws as dedicated disk sanders. If you are converting a saw to a dedicated sander it will work better if you reduce the arbor speed. If the motor runs at 3450 RPM it is best to swap it for one that runs at 1725 RPM, a smaller motor will work for sanding as long as it is 1/3 HP or larger. If the original motor runs at 1725 RPM swap the llarge pulley on it for one the same size as the one on the arbor.