Using a scraper properly

[Scott Brandstetter]

When trying to clean up any tool marks before going to the sandpaper, I would like to use a scraper but have a question. If turning say a 12 inch wide platter, what is the typical speep of the lathe supposed to be? I think I am running it too slow thus causing more issues

[Reed Gray]

I had to take my nap... Okay First speed. As with most phases of turning, proper speed is what you are comfortable with. For me a 12 inch platter would be spinning at 1,000 plus rpm, which is faster than most will use. At that speed, of course, any catch will be pretty spectacular. If the platter is under 1/4 inch thick, at higher speeds, it will deform due to grain orientation being different, kind of in the same way wood warps.

Now, as for the scraper, there are many ways to use it. Flat on the tool rest is a scraping cut, and many will use a more broad nose profile ) instead of U nose or swept back. They will sweep back and forth, using a straight tool rest, and your fingers pinching the scraper and acting as a guide on the tool rest. However, NEVER go near the rim with a scraping cut because it will start the bowl/platter vibrating as in 'my bowl was making was making this strange screeching and howling noise, and then it blew up!'. This is a good cut for leveling out a bunch of the ripples that always seem to be a problem in the bottom of bowls and platters. When scrapers are sweeping back and forth along the flat part, they will cut fairly cleanly. If you are trying to cut down through the fiber, like when roughing, you will get a lot of tear out.

There is also a shear scrape. On the outsides of bowls, most will use a gouge, with the handle dropped very low, and the wings rolled over so you are cutting with the edge, but the bevel is not rubbing. I use scrapers. This same type of cut is used on the inside of bowls and platters. It is more difficult to use the scraper here because the rim of the bowl, banjo, tool rest, and bed can get in the way of the handle. My favorite scraper for shear scraping the insides of the bowl is again the ) nose shape on a scraper. The scraper is rolled up on an edge to 45 or more degrees, just like on the outside, you use feather light cuts. These cuts are so light, you can go uphill or downhill, with and against the grain. It will take several passes to level out tool marks. Note here, ONLY use the lower half of the scraper, never cut above the center of the nose, or you will get a catch. This cut exerts very little pressure on the wood, and can be used near the rim. I do use my hand on the back side as kind of a steady rest. Hand pressure = tool pressure. If your hand is getting hot, you are pushing too hard.

There are also negative rake scrapers. These have a double bevel. Mine is a 45 degree bevel on both sides so I can turn the burr on either side so I can go from right to left, or left to right. Others will be like 60 or 70 degrees on the bottom, and maybe 20 on the top. This is an extremely delicate burr, and is gone in seconds. Because of the double bevel, it is almost catch proof, and exerts almost no pressure on the wood. This is also in part because this is a very dainty cut, and not for any kind of serious stock removal. The negative rake scraper works better on medium and hard woods, but not as well on softer more stringy woods that are hard to cut clean.

I have a number of clips up on You Tube showing all sorts of scraper techniques. Just type on robo hippy

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