46 - Utility Workbench, страница 12

46 - Utility Workbench, страница 12

As a kid, I spent hours opening and closing the vise on my grandfather's workbench. It had massive wood jaws, a wood handle, and best of all, a large wooden screw that threaded in and out of the bench.

Ever since then, I've been fascinated by projects with wood threads. Deep, V-shaped threads spiral around the outside of a wood cylinder. And these threads mesh together with threads inside a hole — like a bolt in a nut, see photo at right.

But to be honest, I've always been a bit intimidated about building a project that required cutting wood threads. To prevent the threaded parts from binding, the threads would have to be identical — inside and out And that sounded complicated.

As it turns out, I was right about one thing. To get the threaded parts to fit smoothly together, the size and

spacing of the threads does have to be consistent. But cutting uniform threads isn't as difficult as it sounds. In fact, all you need are two simple tools.

TAP & THREADBOX. The inside threads are formed by drilling a hole and gradually twisting a tap down into it. (The tap is the metal tool with a T-shaped handle in the photo above.)

To cut the outside threads, you spin a threadbox (the wood block with the turned handles) around a dowel. Note: You can also rout the threads, see page 15. Either way, it's important to start by selecting the right dowels, see box on page 13.

SIZE. Threading tools are available as matched sets that range from V2" to IV2", see Sources on page 31. (The size refers to the dia. of the dowel that can be threaded.) So it's best to have a project in mind before buying a set, see photos below.

▲ Veneer Press. Tightening a single wood screw applies all the clamping pressure that's needed for this small veneer press.

k Small-Piece Clamps. These clamps are ideal for delicate work. Just thread a short dowel. Then tap threads in the lower nut.

A Benchtop Vise. The twin wood screws on this small, benchtop vise thread into tapped holes in the back jaw.

12

ShopNotes

No. 46

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