Читать книгу Ellsworth on Woodturning - David Ellsworth - Страница 35

The tips I make are of two sizes: ³/₁₆" square for all of my bent tools and ¼" square for my straight boring bars. The tips come in 2½"-long sticks, so first cut them in half. This can be done by placing the center of the stick against the corner of the grinding wheel and cutting a V in one side, about three-quarters of the way through the stick. I then break the stick in half, which leaves a very nice angle on the end of each stick that can be integrated into the tip of the tool.

Step two is to round the stem to fit the hole in the shaft. I have a series of jigs set up for this, but it’s easily done in a home workshop. Using vise-grip pliers, grind each of the four corners of one end of the tip separately, starting at the top of the wheel and working down to the base of the wheel. The stem needs to be from ⅜" to ½"-long. With practice, it’s easy to cut a nice round stem. It doesn’t have to be perfect, just round enough to go into a hole of the same size as the tip. Epoxy or gap-filling superglue will make up the difference. Do not overgrind the stem or it will become weak.

The final step is to drill the hole in the shaft using a standard twist drill and glue in the tip.

Recycling tips

As the tips of my hollowing tools grow shorter with use, I find I use them for different purposes. For example, a steeply bent tool is good for use in the shoulder of a hollow form, but as the tip wears away and it becomes shorter, I remove it and place it in a tool with a shorter bend so I can use it more as a roughing-out tool. When the tip becomes really short, I grind the end down so it becomes a straight tool for boring in the center of a smaller form.

As tips wear down, they can be used in different tools. What started out as a long tip in a bent tool for cutting shoulders can become the tip of a roughing tool, and eventually the cutter for a straight boring bar.

Making a tip

To make a tool tip, try cutting your 2½"-long 10% cobalt high-speed cutting tip in half on the grinder at a 45˚ angle.

Grind the cobalt tip almost the whole way through the middle by using the corner of your grinder. Be sure to maintain a 45˚ angle.

The tips will still be attached when you are done with the grinder.

Use your vise and vise-grip pliers to break the tips apart. Bend toward the V angle you have cut.

Grind each corner of the squared end of the tip until the base fits in the hole of the shaft. Start at the top of the grinder wheel and work down to the bottom. The rounded base of the tip should be ⅜" long.

Secure the shaft of the tool in your vise, then drill a ³/₁₆" hole to receive the tip in this ⅜"-diameter shaft.

Apply superglue into the shaft’s hole. Spray the hole and stem with accelerator.

Insert the tip into the hole. Be sure the top surface of the tip is aligned (parallel) with the line of the chamfer on the end of the rod just above the hole. Doing so ensures this and any successive tip used in this tool always seats in the horizontal position in the shaft.

Repurposing tools such as screwdrivers, Allen wrenches, and Irish concrete nails will enable you to reach areas in your smaller turned forms. The first four tools from the left are made from Allen wrenches. The next two are created from Irish concrete nails, with the nail itself between the two tools for reference. The last two tools on the right are repurposed screwdrivers.