How to Replace the Switch on a Dremel Rotary Tool (Model 3000)

The switch assembly allows you to turn your rotary tool ON and OFF and vary the motor's speed. The switch assembly also holds the carbon motor brushes. Power tool switches will wear down over time and eventually need to be replaced. A faulty switch may prevent the tool from turning on, or it may not allow you to change the speed of the tool.

Let's get started.

REMOVING THE SWITCH   1. Remove the collet & collet nut.

a. Unplug the rotary tool.

b. Press the spindle lock button and unscrew the collet nut and the collet.

c. Remove the front collar by unscrewing it from the front of the rotary tool.

  2. Open the main housing.

a. Remove the four screws.

b. Use a utility knife slice through the labels on the sides of the tool. (Cut along the line where the two halves of the housing meet.)

c. Pry apart the two halves of the housing.

  3. Remove the motor and switch.

a. Lift the motor and switch assembly out of the housing.

b. Remove the carbon brushes.

c. Detach the cord wires from the switch using a small pick. (Insert the pick next to the wire to release the "trap door" that secures the wire within the switch.)

d. Remove the switch by pulling it away from the field and over the armature bearing.

INSTALLING THE NEW SWITCH

  4. Install the switch.

a. Slide the new switch assembly over the armature bearing.

b. Align the tabs on the new switch with the slots on the field and press the two components together.

c. Replace the rubber boot over the armature bearing.

  5. Connect the cord wires.

a. Connect the cord wires to the new switch (the wires simply press into the 'trap doors' on the top of the switch).

REASSEMBLING THE UNIT

  6. Reinstall the motor brushes.

a. Install the motor brushes into the brush holders on the new switch.

b. Secure the motor brushes with the brush caps.

  7. Reinstall the motor and switch assembly into the housing.

a. Align the switch lever with the slot on the motor housing and install the motor and switch assembly into the housing.

b. Verify that the internal components (armature, shaft, motor, switch, bearing) are properly aligned with the mounting tabs in the housing.

  8. Install the side covers.

a. Slide the side covers over the brush caps.

b. Align the grooves on the side covers with the tabs that run along the housing.

  9. Reinstall the top half of the housing.

a. Install the top half of the housing onto the unit.

b. Secure the two halves of the housing with the four screws.

  10. Reinstall the front collar, collet, and collet nut.

a. Thread the collar onto the housing (by hand.

b. Insert the collet into the spindle shaft.

c. Secure the collet by fastening the collet nut onto the spindle shaft.