The lower photograph shows the chuck’s construction. The right-hand piece of wood illustrates how a workpiece is gripped by the thread. Alternatively, as shown in figure 4.2, you could hold the threaded rod in a scroll chuck.
Figure 4.2 A loose-pin chuck held in an engineers scroll chuck. The loose pin is hacksawn from a nail.
Figure 4.3 A 1/2″-diameter loose-pin chuck. The rod is cut from a screw, and has a 1/2″ BSW thread which screws into an axial hole with the same thread in the Woodfast-brand faceplate. The diameter of the leading hole (here 1/2″) should be such that the rod is a snug fit within. To lock the workpiece onto the chuck, twist the workpiece clockwise (looking towards the headstock).
Figure 4.4 The loose-pin chuck drawn in figure 4.3.
4.2 BORING THE LEADING HOLE
If a chessman workpiece has been prepared with a flat top and bottom whose surfaces are perpendicular to the man’s longitudinal axis, the leading hole can be bored in a drilling machine. Otherwise turn blanks between centers to produce multiple or single chessman workpieces, each with a chucking spigot (figures 4.5 or 4.6 respectively). Chuck each workpiece by its chucking spigot, cut the bottom very slightly concave, and bore the leading hole as shown in figures 4.7 to 4.10.
Figure 4.5 A workpiece turned into three workpieces, each with a chucking spigot at its right-hand end.
Figure 4.6 A single chessman workpiece ready for chucking by the chucking spigot at its right-hand end.
Figure 4.7 Chucking the workpiece in a scroll chuck, here with dovetail jaws.
Figure 4.8 Flatting the bottom of the chessman slightly concave. The skew’s long point is being pushed slowly forwards in a shallow arc by my left hand (I’m right-handed).
Figure 4.9 Scraping a small conical recess with a skew’s long point to center the point of the drill so that the boring will be truly axial.
Figure 4.10 Boring the workpiece with a 1/2″-diameter drill. The yellow tape is a depth gauge.
Figure 4.11 Chucking the workpiece on a 1/2″-diameter loose pin chuck.
The yellow tape on the chuck rim indicates where the flat in the rod is so that when dechucking the workpiece by twisting it anticlockwise, the loose pin can be on top of the chuck’s flat, and therefore less likely to fall down. If it does, it will be caught by the tray.
Figure 4.12 Chucking a king workpiece on the 1/2″ screwchuck shown in figure 4.1. The headstock spindle is locked, and the tail center is wound forward to keep the workpiece in axial alignment as the workpiece is screwed to the left.
The bored hole needs to be just large enough in diameter so that the screw thread bites. If the hole diameter is too small, the workpiece is too hard to screw on and off: if too large, the thread won’t grip the workpiece securely.
4.3 CHUCKING CHESSMEN WORKPIECES
Whether a chessman workpiece has been bored for leading is likely to affect how you decide to chuck that workpiece for finish-turning and polishing.
If a set’s men won’t be leaded, they can be turned between centers, or cantilevered from a chuck, usually with the men’s bottoms to the left so that their tops can be fully finish-turned in the lathe.
If a set will be bored for leading, and you’ll use either of the chucking methods shown in figures 4.11 and 4.12, this will dictate the diameter and minimum depth of the leading hole. Other chucking methods for leaded chessmen include:
• After boring as in figure 4.10, don’t de-chuck the workpiece for finish-turning. It’s best to use the nose of a preferably live tail center to provide additional support.
• Mount the workpiece between centers.
Other factors which could influence your choices of the sequences of operations and chucking methods are:
• whether it’s preferable to complete each man separately, or perform each operation on all the men before performing the next operation on all the men. For example, if you choose the former approach you might have to repeatedly swap between a drill and a live center in the tailstock swallow
• the chucks, range of drill diameters, and other equipment which you can access
• how you polish the men. If some or all of the polishing operations are best done in the lathe, this may cause you to delay parting-off.
4.4 POLISHING
I don’t have a spraying facility. Also I prefer a gloss finish for chessmen, but not one of perceptible thickness. Because it has no color tint, the polish I prefer is water-based polyurethane.
After a set has been finish-turned, I apply one coat with a brush with the workpiece rotating slowly in the lathe to each man. After the polish has hardened, I sand-back almost to the wood, again with the workpiece chucked in the lathe. I then apply a friction polish such as Shellawax in the lathe. Because I use the lathe for polishing operations, I lead after polishing.
4.5 LEADING
Chess sets are normally