Woodturning Design

Issues	Resources	Subscribe	Advertise	Contact Us


Ask Dale is a regular column featured in Woodturning Design. Listed below are the questions and Dale's answers from Issue 21.
I recently bought a fairly expensive (for me) piece of wood with the intention of making a large salad bowl. Then I realized that more than half my investment will end up in the dust collector. Is there a way to cut out a portion of the middle of the blank, yielding enough to make a small bowl, without purchasing expensive, dedicated equipment?
This is a problem that woodturners have had ever since they began making bowls. Coring or making nested bowls can be traced back to the time of pole lathe turners, prior to the dedicated coring systems of today. Coring with a parting tool (oversized parting tool, usually made in one’s own shop) or slicer tool (such as the slicer tool made by Robert Sorby) cuts in at an angle and produces a flat-sided core, which can be used to turn a smaller bowl. The technique involves turning the bowl to a rough shape, then using a slicing tool to nest the bowl blanks. The simplest method is to use a straight slicer, cutting from the top of the bowl and aiming the cut toward the center of the bowl base. When the diameter of the wood at the base is 2" to 3", the inner bowl or core usually will start vibrating. Stop the lathe and bang the core at the outer edge and the core will usually separate. If not, make the cut a little deeper and repeat the process until the inner core releases. While this is better than turning the interior wood into shavings, the flat-sided core quite limits the shape that can be developed from the core. Wood that is relatively inexpensive, large in size, and readily available could benefit from the “parting tool” coring method, and has been a successful method for many turners. The expensive, dedicated equipment includes a system by Oneway, called the Easy Core System, the Woodcut Bowl Saver, and the McNaughton Center Saver. These are dedicated to bowl turning and are relatively expensive, but considering that these systems save time and money by producing several bowls from a single block of wood, some turners feel they are inexpensive in the long run. “Bowl coring” saves you time, since it is faster to cut bowls from a blank than it is to turn the wood to shavings. These systems produce rough-turned bowls to a basic shape and require less time to finish. Savings can be substantial, with the smaller bowls often selling for enough to cover the cost of the original blank, so the other blanks are free. Fixed-position systems, such as the Woodcut Bowl Saver and the Easy Core System, are fairly easy to use and are probably the best choice for the occasional user. When properly set up, the fixed-position systems will produce uniform and consistent results. The McNaughton system offers versatility not found in the other systems. It allows you to vary the shape, thickness, and diameter of the bowl being removed, but requires more practice to become proficient and produce consistent results.
I am a woodturner from South Africa and would like to know the similarities, differences, and/or comparison of the following in terms of dimensions and design: vases, hollow vessels, closed forms/open forms. In other words, when does a bowl become a platter and a platter become a bowl, and what is the relationship between height, width, and diameter?
Vases come in many different sizes and shapes. In general, the vase form is greater in depth than width and is designed chiefly as a vessel for holding floral arrangements. The top may be flared and quite open, or be restricted and narrow as in bottle vases. Closed-form hollow vessels are not turned to be containers, but are vases and vessels with very small openings of 2" or less. They can be hollowed using conventional scrapers of narrow widths, but undercut rims will require offset cutters or bent hollowing tools. Deep hollowing systems are now commercially available, but until the last few years, turners doing deep hollowing made their own tools. Open forms have openings large enough to accept standard lathe tools and allow room for the tool to function adequately whether using gouges or scrapers. Turned work producing open forms are usually bowls and can range from quite open forms to partially enclosed forms. The depth of the bowls is usually determined by the anticipated use and the thickness of the blank. Domestic use bowls usually are 3" to 6" deep and 9" to 15" in diameter. However, some bowls are much larger than this and some very fine bowls are smaller. Shallow open forms can be platters, plates, or saucers. Platters are usually 1-1/2" thick and 12" or more in diameter, plates are less than 1-1/2" thick and 9" to 12" in diameter, while saucers are around 1" thick and about 6" in diameter.
What is the difference between a “detail gouge” and a “spindle gouge?” As I observe the usage of the two terms in different magazine articles and catalogs, it seems the detail gouge is simply a spindle gouge, but with, perhaps, a different grind. Or is there more to it than that? Thanks for your help in clearing this up.
Gouges are turning tools primarily used to turn center work, where the wood is between centers and the wood fibers are aligned parallel to the lathe axis. Work produced includes stair newel posts and balusters, chair parts, tool handles, light pulls, pepper mills, and other similar objects. I would recommend the 1/2" spindle gouge as the first choice, with a 3/8" next. Spindle gouges have shallow rounded flutes and long fingernail grinds on the ends. The spindle gouge flutes are variable in length, usually around 4-1/2" long. Another popular gouge is the detail gouge, which is also a spindle gouge but is heavier in cross-section, has a longer flute up to 6" to 6-1/2", and the flute is more shallow than a regular spindle gouge. The heavier cross-section allows turners to reach well beyond the tool rest without the associated vibration caused by thinner tools. Detail gouges are used for cutting fine detail, such as beads, decorative grooves, or other decorative work on bowls and spindles. Detail gouges have also been called “long and strong” gouges. The grind angle is the same on the spindle and detail gouges, but will appear longer on the detail gouge due to the greater thickness of the tool. There may be some variation in the grind angle due to the preferences of various turners.
What are the “Rules for Woodturning” as you see them?
We have frequently heard woodturners talk about the Laws of Woodturning, and many tongue-in-cheek comments have been made, some of which are relevant. Seriously, there are some “laws” which need to be followed. In Keith Rowley’s highly recommended book, Woodturning, a Foundation Course, Keith lists six laws which he thought were of primary importance, and I fully agree with him. Law 1. The speed of the lathe must be compatible with the size, weight, and length of the wood to be turned. Law 2. The tool must be on the rest before the whirling timber is engaged, and must remain so whenever the tool is in contact with the wood. Law 3. The bevel (grinding angle) of the cutting tools must rub the wood behind the cut. Law 4. The only part of the tool that should be in contact with the wood is that part of the tool receiving direct support from the tool rest. Law 5. Always cut “downhill” or with the grain. Law 6. Scrapers must be kept perfectly flat (in section) on the tool rest and presented in the “trailing mode,” i.e., with the tool handle higher than the tool edge. Along with the Rowley laws, several others come to mind, but in a humorous mode: You can always make it smaller. It’s only wood, and you can burn it at any stage. Catches are not problems, but rather artistic opportunities. The longer it has been since you had a catch, the closer you are to having one. Nobody gets it right all the time. Practice may not make you perfect, but it certainly produces a lot of shavings. If you’re not having fun, you’re probably doing something wrong. When things happen on the lathe, they happen FAST.
See what else is in this issue. \| Find out how to order this issue.

©2011-2004 All American Crafts
Reproduction of the contents of this website or magazine (including images) in any way whatsoever without written permission of the Publisher is strictly prohibited.
ANY unauthorized use of the materials contained within WILL be prosecuted to the fullest extent of the law.

Woodturning Design Magazine is published by All American Crafts, Inc. View our other magazines.