Pen Turning On The 46-140 Lathe With A Plain-End Pen Mandrel

There are three basic types of pen mandrel, as defined by the method of mounting to the headstock: those having a morse taper shank, those having a threaded female socket, and those having no mounting fixture at all -- the so-called "plain end."

In other words, a "plain end" pen mandrel is basically just a length of straight and smooth round rod with no obvious means of mounting to the 46-140's headstock.

Here's where you get creative. I will explain two similar methods, one for use with a scroll chuck, the other for mounting directly to the headstock spindle.

Let's suppose that you happen to have a scroll chuck with an ordinary 50mm jaw set. Rough turn round and then face off a thick hardwood dowel. Cut off a 3 inch length of it and grasp it in your scroll chuck jaws. Turn down a 1/2-inch long tenon at the tailstock end of that dowel. Drill a 3/4-inch deep hole in the center of that tenon that is just large enough to accept the smooth end of the pen mandrel. Aim for a snug fit. You don't want any play in that hole and it must be perfectly centered. Secure the mandrel in the wood block with a set screw driven into the tenon perpendicular to the axis of rotation. Here's a photo of the finished item. You can see the "tooth marks" where the scroll chuck's jaws grasp the block.

With the mandrel now secured in the wood block, add your pen blank, spacers, etc., tighten it all up, place the dimpled end of the mandrel rod on the point of your tailstock center, and turn your pen.

Alternatively, let's suppose that you have only the factory spur drive center. Unscrew it and set it aside. Now simply tap a hardwood block that is at least 4 inches long by 2 inches square with an ordinary 7/8-14 machinist's tap. Screw it on to the headstock and then follow the above instructions for turning a tenon, etc.