Monday, September 3, 2012

Another powertool modification

First I'm so happy using my small tablesaw but because of my small workshop there is no more space on the table!
Solution: Laptoptablesaw :-)

Another power-tool in the closet I use from time to time is the Proxxon Disc Sander.
Problem is sometimes the piece needed to be sanded is better handled on the right side of the sanding disc and then because of the rotation of the disc the workpiece is pulled away from the table.
Then it hit me. All the other Proxxon tools I have uses direct current motors (DC-motors). DC-motors is easily reversed. The two wires to the motor should just change place.

The  backcover was unmounted and yes the motor was a DC-motor and better there is lots of space for mounting a switch besides the on/off switch and speed-controller.
A hole is drilled and the switch is mounted.

The red and black wires from the circuit-board to the motor is unsoldered and replaced with two new wires that goes to the switch.

Wiring of the switch
And then the cover can be remounted on the sander.

In the process I pulled too much in the wires so the speedcontrol broke. So unsoldering the white and black  wires is a good idea :-) It doesn't matter how the white and black wires is soldered back to the control.

A little theory: Reversing a DC-motor.

The switch used is a Double Pole Double Throw (DPDT) switch.

DPDT switches are available in 'toggle' or 'slide' types, as shown in the picture below.  Both types have six connections - three for each pole of the switch.

The upper, toggle switch is easiest to mount :-)

This circuit shows how to connect one DC motor to a DPDT switch.

At last my Proxxon disc sander with a new miterguide.
 And result of first use.
But that's another story.

Have fun