Faceplates & Faceplate Jigs
by Hal Mahon    hal.mahon@umb.edu

Moveable jaw chucks, screw chucks, spur centers and faceplates are commonly used to hold our work on the lathe. Many of us have devised special faceplates to satisfy the particular conditions we have encountered. This is a description of several types of faceplates I’ve used for holding work on my lathe. Faceplates I have used are: 1) Conventional metal faceplates, 2) a 15” diameter MDF platter with cauls, 3) metal disks adhered with hot melt glue, and 4) an example of a faceplate-jam chuck made from a lawnmower tire.

Commercial Metal Faceplates: First I will mention metal faceplates available commercially. Fig. 1 shows an 8 “ cast iron faceplate screwed to a 15 ½ “ diameter rough sawn spalted maple blank. The eight hex-head steel screws holding the faceplate are #12-1” long. Screws 1.5” long or even longer would be recommended if the wood is soft or punky.  The popular hardened steel screws that are highly valued for their compressive strength are not recommended for holding faceplates because they have poor shear strength. Heavy duty faceplates with 8” and 4” diameters are available from Sears (1-800-377-7414) at less than 1/3 the price from prominent sources. Other sources for faceplates at good prices are Penn State (1-800-377-7297) and Grizzly (1-800-523-4777). Using these sources I find it affordable to have multiple faceplates so that I can leave them on special purpose jigs, and have several available for work in progress. Penn State offers spindle converters (at 1/3^rd the price of others) for adapting faceplates to lathes with different headstock threads.

Another purpose of Fig. 1 is to show the center marker lying on the faceplate. This jig is a quick do-it-yourself project. It is made of ash from the fire wood pile and has been turned so that the diameter of its small end fits snugly inside the spindle threads of the faceplate. A hole was drilled through the center marker of size for a center punch from your tool box or hardware store. This tool is helpful for centering the faceplate on this very heavy maple blank.

It is often essential to know the exact center of the bottom of a bowl before the faceplate is removed. The center marker is fitted inside the threads of the faceplate and the center punch is tapped to leave an indentation marking the exact center of the base of the bowl. This will allow the precise centering of the bowl as the point of the tailstock is located on this indentation. The mouth of the bowl can then be centered onto a jam chuck, as described below, or vacuum chuck (to be discussed in a future article) before the tailstock is withdrawn. Now the bottom of the bowl may be turned to final shape.

MDF Platter with Cauls: The 15” diameter Medium Density Fiberboard platter shown in Fig. 2 is an easy construction for holding a variety of lesser diameter bowls and sector rings. MDF is flat and does not warp. The 15” diameter platter has been turned from two, glued together ¾” inch thick pieces of MDF. The 15” diameter is slightly less than the maximum diameter that will swing over the bed of my lathe. Any deflection of this 1 ½” thick platter is negligible. A 4” cast iron faceplate is centered on the other side of the platter, and screws on to the spindle.

The cauls may be relocated roughly to fit the approximate diameter of the piece to be held, while the 10-32 screws provide for fine centering adjustment. The screws are aimed down toward the surface of the platter. When necessary, they may be padded with cardboard or, as shown, the plastic caps from snow markers. Pencil erasers also work well. In use the three screws have provided ample holding power. Detail for a padded 10-32 screw is given in Fig. 3

In Fig.4 a ring for a segmented bowl is held in the lathe for flattening before gluing to adjacent rings. This is one of the many examples where a vacuum chuck would not be suitable. Other examples in which this MDF faceplate is useful include wormy bowls, bowls from porous wood, and feature defects that defeat the use of a vacuum chuck.

This Fig. 5 shows an Angelique faceplate glued to the cherry bottom of this sector bowl. The sector bowl is mounted on the platter for the purpose of turning this 1 ¼” thick faceplate thinner to meet the design proportion intended for this bowl.

Metal Disks: Fig. 6 shows faceplates of metal disks adhered with hot melt glue. These disks are aluminum scraps salvaged from the waste bin of a machine shop and range from 2 ½ to 4 inches in diameter and ¾ to 2 inches thickness. The two examples at the right hand rear are affixed off axis or off center for eccentric turning intended for non-functional artistic expression. Disks may be easily relocated as shaping proceeds to turn about a new axis. As someone relatively new to wood turning I have enjoyed trying new ideas as I learn. This method of holding work for eccentric turning is certainly inexpensive compared to the hundreds of dollars for commercial chucks. Fig. 7 gives another view of the off-center positioning of the aluminum disk. Also shown is the use of a steel washer purchased from the hardware store.

The secret of obtaining a strong bond with hot melt glue lies in achieving a higher temperature than is possible with a glue gun.  I apply hot melt glue to the disk with the disk at a temperature above 500 degrees Fahrenheit. With the work upside down and its bottom surface level, the glue laden disk is then removed from the hotplate with pliers and centered on the work. The hot disk transfers heat to the work so that the wood under the disk is raised to a temperature such that a good bond is achieved. Excess glue may be squeezed from the joint by pressing with the pliers. Then with the glue still molten the joint must be left undisturbed until it is cool. Joint failures I have experienced were due to repositioning disks after the glue started to cool. On a non-level surface these disks had migrated from center position.

Fig. 8 shows initial heating to remove the metal faceplate. The hotplate has been set to a temperature well above the glue melting temperature--- between 500 and 800 degrees Fahrenheit.  As soon as the bond starts to loosen the piece is removed and the disk slid from the wood. Glue remaining on the wood may be scraped off or turned off on the lathe. Using these steps for making the bond and removing the disk the temperature of the wood remains well below that where any damage could occur.

Faceplate-Jam Chuck: A jam chuck is a faceplate tightly fitting into the opening of a vase or bowl. Usually a jam chuck is turned from a scrap piece of wood onto which is screwed a commercial faceplate fitting the threads of the headstock. Other objects may be recycled for this purpose with a possible saving of effort, as for example wheels with hubs fitting your commercial 4-jaw chuck. Fig. 9 shows an example of a faceplate-jam chuck about to be turned to diameter from a lawnmower tire. No additional faceplate is necessary as the hub of this tire already fits my 4-jaw chuck. The size of this wheel is slightly larger than the opening of my bowl. (Also note the second banjo that I keep next to the headstock for working on the other side of large bowls although not used for this example.)

Fig. 10 shows the jam chuck after it has been turned to the diameter that will tightly fit into the mouth of my bowl. This shows centering my bowl onto this jam chuck with the help of the point on the tailstock. The tailstock point has been located into the depression made with the center marker visible in Fig. 1 and using the procedure explained above. Force applied from the tailstock presses my bowl tightly onto the jam chuck. Although not necessary in my case, transfer of discoloration from a tire with such rubber to a bowl could be avoided by putting on a layer of duct tape.

In Fig. 11 we can see my bowl held for turning off the tenon and finishing its base. (In this view we can see there is insufficient room to move the banjo to the bottom side of the bowl, and thus the advantage of having a second banjo on this side for working on the bottom.) This bowl began its life as the piece of maple in Fig. 1. There are numerous beetle holes that add to the rich character of this bowl. These holes preclude use of a vacuum chuck and its large diameter precludes use of my MDF faceplate. The use of the jam chuck was an alternative I envisaged when I began my bowl.

In this article I have described a variety of faceplates I have used. Please take a photo of your creative ideas and submit them in response to this article. I believe this news letter would like to publish them.

+++
Jun 2006