Pentel Pencil Conversion Tips

Drilling:

It is suggested that a regular 17/64 drill be used to drill as much of the pen blank as possible and use the Step Drill for drilling the last inch or so of the blank.  This will keep the drill bit as sharp as possible for a longer period of time.  The depth collar is preset  for a 4 7/16” blank.  Slight adjustment may be necessary depending on the length of the blank you use.

Blank and Turning:

I use a 4 7/16” blank though a blank up to about 4 ½ “ will work as well.  The end bushings are sized to allow a slight taper at both ends.  I find a diameter in the center of the blank of about .370 or so is about right for my taste.


All version of the conversion include a 5/32 inch step.  A blank should be turnned round before drilling and mounting on any of these mandrels to greatly reduce the possibility of damaging the mandrel.

Mandrel Selection

"Perfect" Pentel Pencil Conversion Mandrel

This mandrel is sized for the 17/64 step drill bit.  It comes with two sizing bushings, two finishing bushings, two 1/4 by 28 nuts and two 5/32 by 32 tpi nuts.  The nuts tighten against themselves to apply just the right amount of pressure while turning.  

The perfect mandrel includes a chuck gripping step that eliminates the need to grip threads.  The gripping area is the standard configuration but it can be special ordered with full threads if desired.  

This mandrel is best suited for use when a drilled blank is immediately mounted on the mandrel for turning.  Many woods and some other materials tend to warp, twist, turn, bend, shink, expand etc when drilled and left to sit more than a few hours.  Since this mandrel only allows a couple of thousandths clearance a blank that has changed shape can be difficult to get on and off the mandrel if these changes occur.  If you frequently drill many blanks at the same time and then store them for later turning one of the other mandrels may be a better choice.

"Deluxe" Pentel Pencil Conversion Mandrel

This mandrel is styled much like the Perfect version.  The bushings and mounting nuts are optional and the shaft itself is thinner allowing greater tolarance when working with a drilled blank that has moved after drilling.  There are several thousandths available for perfect adjustment to aid in mounting or removing the mandrel.  I have been using the blue painters tape when making this adjustment and find it works very well.  You may find other materials work equally as well.  

This mandrel uses the same type chuck gripping area use in the Perfect version.

"Original" Pentel Pencil Conversion Mandrel

This is the workhorse style I designed seven years ago and have been using the same mandrel all those years.  It uses the thinner mandrel shaft that can be perfectly adjusted as above and mounts in the chuck by the smaller end.  The benefit of mounting by the smaller end is that it allow the shortest possible entension where these mandrel are the weakest (5/32").  Most of 5/32 end step is supported by the chuck reducing the possibility of bending the mandrel.

Bushings and nuts are optional on this mandrel.