How to Replace the Collet Nut on a Dremel Rotary Tool (Model 4000)
Finish Nailer Repair - Replacing the Driver Guide (Ridgid Part # 79004001022)
The collet nut works with the collet to firmly secure the rotary tool bits. The collet nut threads onto the tool's rotary shaft and has a taper milled onto the end, which matches the taper on the collet. When the collet nut is tightened, it draws onto the collet where it closes tightly around the bit. Over time, the threads on the collet nut can wear out (or the tapered surface can become dull). This will require the collet nut to be replaced.
Let's get started.
REMOVING THE COLLET NUT
1. Remove the collet nut.
a. Depress the spindle-lock button to lock the spindle.
b. Unthread and remove the collet nut from the tool.
INSTALLING THE NEW COLLET NUT
2. Install the collet nut.
a. Lock the spindle.
b. Install and tighten the new collet nut.