Be sure to touch up your edge on the grinder before making your final cut. A dull tool will pull or tear at the fibers, leaving a surface that you can’t sand smooth. This is especially true on end grain.
Each instructor will show you his or her favorite grind for the bowl gouge. They all work if you take the time to learn how to use them. It is more important that you learn to consistently reproduce the grind you are using than which profile you choose. Grinding by hand is important to learn, but for the beginner, jigs and fixtures are a great help. 16. Too Much Pressure. Another common problem is applying too much pressure when cutting the surface. This will force the heel of the tool into the surface and bruise the fibers, leaving lines that remain invisible until you apply finish. Yikes! These lines are almost impossible to sand away. You must recut the surface. Relax and let the cutting edge do the work rather than forcing it. THE RIGHT MOUNT A lot of bowl-turning problems begin with how the material is attached to the lathe. Because every new lathe is shipped with a faceplate, this is the obvious choice for the beginning woodturner. Stop! Don’t do that!
If you want your bowl to stay in the chuck, you’ll learn the value of properly sizing the tenon. If the chuck loosens, the bowl will fly out off the lathe.
Sheet metal screws are a better choice to attach turning stock to a faceplate. These screws are casehardened and have deeper and sharper threads. Make sure you choose a length that is appropriate. Square-drive screws are also popular and are much easier to remove from hardwood. For securing turning stock, one size does not fit all. For an 8"-diameter blank that is up to about 2" thick, I recommend #8×¾" screws. For a 14×8" blank, secure with #14×1 1/2" hardened screws.
17. Wrong Screws. Trouble can begin at the first step when you screw the blank to the faceplate. Here, several problems can occur. It usually starts with drywall screws; they are too thin and too brittle. You exacerbate the problem when you draw up drywall screws with a power screwdriver, which pulls them up tight and snaps them.
18. Difficult Grain. You must also consider the material you will be putting the screws into. End grain requires larger and longer screws. Beware of punky or spalted woods; once the wood has started to decay, it is extremely difficult to get a screw to hold. Sapwood does not hold screws as well as heartwood. To be on the safe side, bring up the tailstock with a live center for insurance. This will give additional support if the screws do not hold. Choose turning stock that offers a better chance for success. Dale Nish says it best: “Life is too short to turn crappy wood!”
19. Poor Grip. Once you get excited about turning, it probably won’t be long before you purchase a 4-jaw scroll chuck, which I think holds material better on the lathe. However, this chuck has its own set of challenges. I have had many instances where students have made tenons too small or the recesses too shallow. Either case can cause the blank to separate from the chuck. Punky wood and sapwood present the same challenges and grain problems as noted above. 20. Loose Fit. Green wood requires you to tighten the jaws of the chuck repeatedly as moisture is forced from the blank. Just as with the faceplate, remember to use the tailstock and center whenever possible. Turn safely and have fun. But by all means, think about what you are doing and consider the risks involved. If you are unsure, ask someone with more experience. If it looks dangerous, it probably is. “Stop, don’t do that!”
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Sheet-metal screws should be your only choice for mounting turning stock to faceplates. At right, you can see how a drywall screw can break off, which leads to huge safety issues. July-August, 2013
Woodworker West