Dr. Wood Discusses:

The Lathe:


Remember that all power tools are potentially dangerous. Always wear eye and ear protection when using woodworking tools. Read and understand the manuals and instructions provided with your tools, and never use a tool in a way that endangers you or those around you.

Whether you want to make chair legs, bed posts, table pedestals, or newel posts and balusters for stairways you will be turning on the lathe. The lathe is also finding increased popularity with the hobbyist woodworker for turning bowls and other decorative items. Woodturning is fast and does not require a shop full of other tools to achieve stunning results.

Woodturning is the fastest growing discipline in woodworking. New lathe designs, novel cutting tools and accessories, and particularly new project kits have fueled the renaissance in turning. No longer is the lathe a tool stored at the back of the shop under a tarp and only brought out to turn the occasional chair leg. It has taken center stage in many woodworker's shops as a source of artistic expression and financial reward.

Turning wood on a lathe is different from every other type of woodworking because the wood is moving and the cutting edge is stationary. This means that the turner is in complete control of the design and execution of the work. Turning is a dynamic process in which the woodworker becomes sculptor: removing waste from the starting piece and deciding when the finished project has been achieved. This process is both the challenge and the nemesis of the woodturner.

The lathe is a simple and ancient tool. Bodgers in medieval Europe powered their lathes with Birch and Beech tree limbs. A rope was tied around an overhanging limb in the forest and thence down around the work to a foot treadle. Stepping on the treadle caused the piece to revolve back and forth with the limb acting as a spring. This simple process allowed the manufacture of chair parts and bowls. Turning on foot-powered treadle lathes became an apartment pastime in the French court of the 17th and 18th centuries. Today most turning for furniture manufacture is done on computerized machine lathes that turn 10 to 30 pieces at a time, but the satisfaction of personal control and artistic expression is still available to the woodturner.

A lathe is a machine that makes wood spin around in circles. If the grain of the wood is parallel to the axis of rotation it is called spindle turning (such as for chair legs and candle sticks), while if the grain runs perpendicular to the rotation it is called faceplate turning (used for bowls and platters). This latter name derives from the flat faceplate we use to attach the wood to the lathe. The part of the lathe to the left of the machine where the motor is located is called the headstock. The wood is connected to the motor by way of a spindle that is driven by a belt and step pulleys. The headstock spindle is threaded to accept face plates and bored down the center to hold the spur drive during spindle turning. This bored hole is not straight, but has tapered walls to hold the spur by friction. The size of this bore is either a number one Morse taper(#1 MT) or a #2 MT, with a #2 MT being the larger.

At the end of the lathe opposite the headstock is the tailstock. It is designed to hold up the other end of the wood spindle during work, and is fitted with a 'center' that is driven into the wood. The center is held in the tailstock because it, too has a Morse taper. Today most turners use a center with a ball bearing to reduce friction, called a 'live-center'. Between the head and tail-stock is the tool rest. This is a horizontal piece of steel that the turner rests the tool on during turning, employing it somewhat as a tailstock and tool rest are all supported on the bed, or ways. In better tools the bed is a machined cast iron structure that securely supports the other parts of the lathe, but on smaller lathes and some English lathes the ways consist of one or two rods or tubes. Mass is critical for lathe performance, and the best lathes are huge, heavy affairs. Mass reduces vibration, and when you are holding the cutting surfaces in your hand you want to eliminate all sources of vibration. However, if you already own a lathe that you suspect is too light, mass can be added with sand, bricks, steel or concrete.

Turning tools come in many shapes and sizes, but the fundamental difference between most turning tools is whether they are manufactured from high carbon steel or from high-speed steel. Carbon steel tools are made from the same material used to make carving tools. While this material is preferred for tools that require a surgically sharp edge, carbon steel is too soft and heat-sensitive for the rigors of woodturning. This is why high-speed steel is used for all the best turning tools today. Good high-speed steel has a high tungsten and vanadium content that makes it very resistant to abrasion, as well as being impervious to the intense heat generated at the wood-tool interface during the turning of hard woods. Thus, tools made from high-speed steel retain their edge and will not lose their temper (hardness, not emotion) during use, both of which are problems with carbon steel tools. Do you have high-speed or carbon steel turning tools? It is easy to check during sharpening on the bench grinder. The sparks from high-speed steel are orange and stay together, while carbon steel sparks are yellow and fly apart. Try it for yourself!

Wood can be removed during turning by either cutting or scraping. While there is a place for scraping in some turning operations, I always encourage my students to cut the wood whenever possible. The use of a cutting technique slices through the wood fibers rather than tearing them, resulting is a superior finish that requires much less sanding (my regular readers will remember that I hate to sand). Wood turning tools are all cutting tools when used and sharpened properly, even those called 'scrapers'. If you have questions on sharpening turning tools I encourage you to attend one of our free Saturday seminars on the topic or consult one of the books mentioned at the end of this article.

Whether you are turning a candle stick or a bowl, cutting technique will speed up the process and give a more satisfactory outcome. The battle cry in my turning classes is "keep the bevel on the wood". All turning tools have a bevel ground into them that forms the cutting edge. A gouge is a single bevel tool with a gullet formed into a bar or slab of steel. Different sizes and shapes of gouge are used for both rapid stock removal and for delicate detail turning. A skew chisel is a double bevel cutting tool shaped somewhat like a carving or bench chisel. The skew is used for long straight cuts and detail turning. With either of these tools it is important to keep the bevel on the wood and cut. When you come off the bevel bad things can happen -- you can tear your work or get a catch that can damage or ruin your efforts.

The other basic tools in the turner's toolkit are the parting tool and various scrapers. Like the furniture scraper, the turning scrapers cut by virtue of a burr raised on the edge during sharpening. It is the burr that cuts, and without it the tool is useless. There is a wide variety of scraper shapes ranging from round to square to diamond-shaped. Dozens of turning tool shapes and sizes have been developed to handle particular turning jobs, and new tools enter the market each year.

In addition to the traditional spindle and bowl projects familiar to most turners, new project kits have become available in recent years. By far the most popular are kits to turn pens and pencils. These are all mandrel-based projects, meaning that a steel rod is mounted between the head and tail stock onto which the pen parts are placed and turned. There are Cross, Mont Blanch, and Parker-style pens, pencils, rollerball and fountain pen kits. It seems that everyone from middle-school students to retirees with access to a lathe has begun turning pens. Pens are a quick and relatively easy way to get into turning, and the pens can be quite stunning and profitable. Students in my classes with absolutely no shop experience have turned lovely writing instruments in less than two hours. Other mandrel-based projects are continually being introduced, but the turner does not need to rely on these projects. Creativity and imagination are the name of the game in turning, and no piece of wood is too small to be turned into something (this is both a blessing and a curse since it means no piece of wood is too small to throw away!).

      If you want more information on lathes and turning I suggest you consult one of the growing number of books and videos on the subject. The book and companion video entitled "Turning Wood" by Australian turner Richard Raffan are outstanding resources for the novice and experienced turner, alike. Del Stubbs video on bowl turning is a classic, and a new book "The Lathe Book" by Ernie Conover is very informative. New videos by Chris Stott and John Jordan give lots of great tips and insight into both open and hollow forms. I also encourage aspiring turners to contact their local chapter of the American Association of Woodturners, (www.woodturner.org).

      The techniques discussed in this article are intended to serve as a guide to the aspiring woodworker. The individual must recognize that there are dangers in any form of woodworking and use all safety precautions. Neither the author nor The Cutting Edge, Inc. can be held responsible for accidents resulting from the application of techniques discussed in this editorial.
                                                
Copyright 1995, 1997, 2006 Stephen LeGrue

 

CUTTING EDGE HOME PAGE

CATALOG HOME
| TURNING | LATHES | CARVING | HAND TOOLS |

SHARPENING | PROJECTS | BOOKS