Woodworker's Journal 2008-32-1, страница 20
Preparing the Turning Blank Cut down a tree ... actually, there's so much free wood around, you'll be inundated with logs if ever you make the mistake of letting friends and family know that you want wood! I know this firsthand. Select a log, cut it to a bowl-diameter length, then cut it apart along the pith. You can do this with a chain-saw or on your band saw. Next, cut the half-log section round. The band saw is the best machine to use. Check your bowl blank for major cracks. I personally avoid all cracks in green wood, as they often end up expanding over time. I remove the bark before I put the wood onto the lathe as it tends to fly off in huge sections during the turning process. Keep the center marked, and also mark the center on the opposite side. I have round cardboard forms in a variety of sizes with a hole in the center for this purpose. If you are going to leave the bark on, you must remove bark where the drive center will be positioned. Turning the Tenon You will need to turn either a recess or a tenon on your bowl blank so the chuck will have something to grab into or onto. The method of mounting the blank onto your lathe is the same for both. For this article, I am rough-turn-ing a bowl blank from green wood, and the bottom of the bowl is next to the bark-edge of the bowl blank. That's where I will turn a tenon to accept the chuck. You can mount the bowl blank between centers as shown in the photos on the next page, or you can use a screw chuck. If you use a screw chuck, you will need to drill a pilot hole to accept the screw. Screw chucks are an accessory for chucks, and they are also available as dedicated screw-center chucks or screw-center faceplates. I mount the wood between centers so the bottom of the bowl is at the tailstock of my lathe, making it easier to turn the tenon. Make sure the wood is securely fastened between centers, as some lathe's tailstocks tend to creep backwards instead of tightening. As you progress with turning the tenon, check to make sure the tailstock is still tight. To begin with, set your lathe's speed at a slow RPM, somewhere less than 800 RPM, just to make Woodturning continues on page 32... European reliability at affordable prices! 2-year manufacturer's warranty PK 250A Cabinet Saw with 59" Aluminum Sliding Table MSP 315 12" or 16" Planer/Jointer Visit us At TECH MARK, INC. (Circle No. 95 on PRODUCT INFORMATION form) Woodworker's Journal February 2008 31 |
