Woodworker's Central Woodworker's Gazette Gazette Archive 5/28/98

Plate Joinery - Part I: by Chuck Ring Maligned or praised... biscuit joinery, as it is referred to in the United States and Canada, first got it's start in Europe. Herman Steiner, a Swiss cabinetmaker, developed and manufactured the first plates under the proprietary name Lamello. Lamello is derived from the German word "lamelle" which translate to "thin plate". Today, Steiner Lamello, Ltd. has grown to manufacture a full line of plate joiner equipment, several sizes of biscuits, special application machines and accessory items. All of Lamello's products capitalize on the ease of use and adaptability of Mr. Steiner's original inventions. Made known and first marketed in the United States some twenty years past...plate joinery was slow to catch the eye and hands of the American Woodworker. Speculation on why the popularity of the system was slow to catch on ranges from suggestions of outright rejection to unperceived value on the part of the woodworker, but I believe the latter is probably the primary cause of it failure to initially catch on. Steiner's plate joiner was and still is the most expensive joiner on the market. The Lamello Top Ten usually list for $699.00, although it is often sold for around $559.00 by one major mail order firm. Now thanks to Freud, Porter-Cable, Makita, Ryobi, Delta, Skil, lower priced Lamello machines, OEM machines, the much-heralded DeWalt and other brands, even the hobbyist on a budget can afford to enjoy the simplicity and versatility of biscuit joinery. One company has even made an adapter for a hand-held electric grinder which allows for slotting for the three conventional biscuit sizes. Companies such as Woodhaven have developed proprietary biscuits and router bits which provide an even less expensive way to enter the biscuit joinery craze. Eventually, this article will attempt to cover the latest in biscuit sizes and accessories for special applications such as knock-down construction, hinges and "clamping" biscuits". For now, we will deal with the basic operation of the machine and the three common sizes of biscuits. How A Biscuit Joiner Works If you compare many of the plate joiners to hand-held electric grinders, you will find the shape and other attributes to be strikingly similar. In fact, in some cases the basic electric grinder was simply converted to a plate joiner by some manufacturers. With the added base for stabilization and plunging action, the tool was easily converted to its new use. The basic operation of the plate joiner depends on the ability of the faceplate to slide backward and forward, so that in turn a four inch blade is plunged into the workpiece. The blade cuts a slot which approximates the shape of the plate which is to be inserted in the slot.. As there is a certain amount of lateral torque from the action of the motor and blade as the machine is plunged, most plate joiners have some sort of anti-skid feature. This feature may be small retractable pins, rubber surfaced face plates or simply a raised and roughened area on the faceplate. Types Of Joints While there are many joints and applications to be made with a plate joiner, there are basically four joints which are in common use. Other types will be discussed later in this article, but for now the basic four will be covered Edge To Edge-While some may disagree, I feel one of the joints which biscuits enhance is the edge to edge lamination such as found in a table top or other panel. In this application, biscuits provide little, if any, added strength, however in my experience they are unsurpassed in allowing for easy and accurate alignment of the assembled components. Miter joints- Whether for frames, boxes or columns are also strengthened and aligned easily with biscuit joints. A plate joiner with an adjustable fence makes quick work of the assembly of a five or more sided column or a simple rectangular box with mitered corners. Butt joinery- Edge to end grain joinery is quickly accomplished with a plate joiner. Cabinet face frames and picture frames are just two of the assemblies which can be made with this joint. Other Butt Joints-Carcase partitions and other dividers as well as carcase tops and bottoms can be accurately made with the plate joiner. Biscuits-The Three Conventional Sizes There are at least nine sizes or configurations of biscuits made from wood or wood products. Conventional biscuits are made from compressed and die stamped beech. Beech trees are first cut to length, dried, squared and then milled into lath material. The lath material is then compressed and stamped into the various sized biscuits. The three standard sizes (0, 10, and 20) will be discussed first, with the remaining to be covered later. #0=5/8" wide X 1 3/4" long #10=3/4" wide X 2 1/8" long #20=1" wide X 2 3/8" long All of the above biscuits are .148 " thick and all manufacturers of biscuits fairly well adhere to this standard. The tolerances between the thickness of the biscuits and the width of the slot cut for them is important, but not entirely critical. The blade of the cutter machines a slot which is 5/32" or .156" wide. The biscuit as it absorbs moisture from the glue or other source swells to .164"(+-) thus insuring an extremely strong bond between the slot wall and the edges and sides of the biscuit. The length of the slot varies with the setting of the plunge mechanism. It is important to take the slot length into account to insure that the cutter will not "bust out" the edge or ends of any of the components being joined. Following are the slot lengths for each of the standard biscuits: #0-2 3/16" #10-2 7/16" #20-2 5/8" Slightly more(1/32"-1/16") should be added to each of the above measurements(especially on softer materials) to insure that the blade does not push through the ends or edges of the material due to movement of the machine or its torque. Continue to Part II