LARGE DIAMETER CHUCK

A simple drill chuck with two applications:

1. Sanding dowels or PVC pipe
2. Self-centering drill jig for ¼” dia holes
   Works with stock sizes from 5/8” to 1.5” (actually up to 40mm) diameter

Parts required in addition to the prints:

1. Four M3 x 16 LG button head screws
2. Two ¼” I/D x 3/8” long flanged bush (McMaster Carr 2938T2)
3. One 3/8” x 2.5” long hex head bolt
4. One 3/8” Hex jamb (thin) nut
   NOTES:
   Assembly: Ensure the jaws are installed in a clockwise direction (1 dot, two dots, three dots) looking at the front.
   Install jaws before joining the ring nut. Put a dot of grease on the thread of the M3 screws before installation.
   Jaws have no stop to prevent over extension. If they do come out, (by attempting to clamp less than 5/8” dia) they can be re-inserted simultaneously with care.
   To clamp the dowel/pipe, hold the three ‘fins’ to prevent the body from rotating while you tighten the ring nut.
   Install the bolt and nut for sanding
   Install the two bushes for drilling
   The two flanged bushes are a tight fit but can be removed with the use of a small diameter drift (rod).
   When drilling a dowel, insert drill bit up to end of dowel (through both bushes) before cutting the hole. Drill at correct speed as quickly as possible. When removing the bit, rotate it very slowly. Allow the bushes to cool between use. These steps help prevent heat buildup in the bushes and subsequent softening of the print.
   If the inner bush wants to drop out, add a small spacer print to hold it in place.
   Once the ¼” hole is drilled, a larger hole (eg: 5/16” for a pronged T-nut) can be drilled by hand
   When using the chuck to sand dowels in a floor standing drill press, I recommend a speed of 450 ~ 500 rpm. The chuck can also be used in a hand drill. Take care holding the sandpaper as the dowel rotates.
   For a ribbed jaw finish, print the jaws on their inner flat face with support on the clamping face
   For a smooth jaw face, print the jaws on a side (no supports). A thin, self-adhesive rubber strip can be added to the jaw faces if desired.

Jaws and nut: 4 walls, 25% gyroid infill, 5 top and 5 bottom layers.
Body: 4 walls, 25% gyroid infill.
Filament: PETG