Iowa State University

College of Engineering

Department of Industrial and Manufacturing Systems Engineering

Module 3.2 - Assembly of components
Loading your tools properly in the collets and tool holders is a critical step in setting up the machine and should be done carefully to reduce the risk of breaking a tool and/or getting injured.
1. Begin by choosing a collet matching the diameter of your tool such that the shank of the tool easily slides into the hole.
Collet and nut assembly
The collet and nut need to be assembled before mounting to the tool holder.
Inserting the collet
You will see that there is a small groove on the thicker end of the collet. This groove must be snapped into the nut before mounting to the tool holder. To do this, push the collet into the back of the nut at a slight angle, then twist it and align it with the axis of the nut until you hear it "click" into place. As such, it should rotate freely inside the nut.

Checking for clearance
At this point it is a good idea to check to see that your tool easily slides into the hole in the collet. If not, you might have the wrong collet, or you did not properly snap it into place.
Insert tool holder
Place the tool holder into the fixture. You need to align the slots in the tool holder with the tabs in the fixture. Also, the tool holder will only go into the fixture in one orientation. The slots are slightly different in width, as are the tabs on the fixture. You can easily figure out the orientation, by facing the slot with the small tapered hole inside it toward you.
Align tool holder
Place collet and nut
Now you can take the collet and nut and slightly screw it onto the tool holder. (You may need to do this sideways in order to keep the collet from falling back out of the nut, and then put the assembled tool holder back in the fixture.)

Tighten slightly
Insert tool
Place the tool shank into the collet. (If it seems too tight, you may have screwed the nut on too much). You'll need to hold the tool with the shank in the collet at a proper depth, while hand-tightening the nut.
8. Finally, use a wrench and tighten the nut down. This needs to be tight, but you can damage the collet if you over-tighten.