Many turners wear gloves to protect their hands from hot shavings, flying bark, or other uncomfortable material removed by the cutting tools. A glove is usually worn on the left hand because this is the hand that often holds the tool in contact with the tool rest and thus is the hand being bombarded with the shavings cut from the work.
I wear a glove for roughing out green bowls as the shavings are rough and fairly heavy, but pieces of bark are also uncomfortable due to the hard, abrasive nature of the material.
The glove of choice is leather, and I usually have a few well-used, left-handed gloves which have worn out more quickly than the right-handed glove.

I have never heard of an accident caused by wearing a glove while turning. However, the general rule still applies. Don’t wear gloves while working on machinery such as table saws, bandsaws, or any shop equipment where the glove may get caught and pull your hand into the cutters.

To answer this question, I would need a lot more information such as the type of wheel, size of the wheel, what type of grinding is done on it, etc. But here goes…

I will assume the grinder is a typical over-the-counter unit and was purchased for sharpening tools. If so, the abrasive wheels are silicon carbide designed for grinding carbon steel and sharpening lawn mower blades, plane irons, chisels, etc. The wheels may commonly be loaded with other materials such as aluminum or brass and, therefore, will cut inefficiently.

If you are sharpening high speed steel (HSS) turning tools and the wheels are gray silicon carbide (as those that are on the grinder when purchased), they should be replaced with aluminum oxide wheels.

Assuming all you want to do is routine maintenance, the wheels need to be dressed and trued up if they are out-of-round. This can be done with a multi-stone Diamond dresser. This tool is 1" wide with about a 1/4"-thick dresser face consisting of 1-1/2 carats of industrial diamonds embedded in a silicon carbide matrix. The diamond dresser will break down glazed areas and, at the same time, produce new cutting surfaces which are needed for fast and cool grinding of tools.

Anytime a wheel gets glazed or loaded on its cutting surface, it will grind much slower and, as a result, heat will build up, making the tool bevel much hotter. It warms the same with cutting edge tools or screwdrivers. If the face of the wheel does not look clean and sharp and shows signs of metal on the face, it needs to be dressed.

If you’re satisfied with the results you are getting from your abrasive wheel, it doesn’t need to be replaced unless it is worn down from use, is badly chipped, or is the wrong wheel for the tools you are grinding. However, when the wheel is reduced 3/4" to 1" in diameter, it loses effectiveness, particularly when using grinding jigs.

If you are using your grinder for sharpening HSS turning tools, you need to replace the wheels with aluminum oxide wheels. I recommend that one is coarse (46 grit) and the other is fine (100 grit). If the grinder is used for other purposes as well, you can just replace one of the wheels and leave a gray silicon carbide wheel in place for general use. In this case, I would put on a medium wheel (60 grit) for HSS sharpening.

It may seem strange, but abrasive wheels for sharpening the hard HSS tools are softer than regular wheels used for grinding softer steel. There are several brands of aluminum oxide wheels and some will be quite expensive, perhaps $80 to $100 for an 8" wheel. Six-inch wheels will cost relatively less, but the more expensive 8" wheels will last longer and sharpen tools quicker. You get what you pay for, and cheap wheels are usually no bargain!

If you are considering purchasing new wheels, learn the code and its meaning. The code is stamped on the disc which is glued to the wheel (see Diagram B).

Some things to watch for are:
1.) Make sure the grinding wheel has a maximum RPM rating of at least twice the grinder speed;
2.) Always wear a Plexiglas face shield when working on the grinder;
3.) Grinding wheels come in both hard and soft varieties (see label).
     Hard metals require a soft wheel while soft metals require a hard wheel. HSS requires a soft wheel; and
4.) It is good practice to buy your wheels from an industrial supply house or a reputable catalog source.

Note: Always stand to the inside of the wheel when turning it on in case it flies apart.

Negative angle scraping is not new. In fact, it has been used for hundreds of years by turners working blackwood and ivory. Simply, this approach is similar to laying a skew chisel down flat and using the edge as a scraper. However, some of today’s turners, such as Stuart Batty, are using negative angle scraping with a burr that is left on the cutting edge. It is this negative angle with the burr that makes this technique special. Negative rake scraping is when the end of the scraper is ground with two angles. The top surface of the tool is first ground at an angle, and then the underside is ground to another angle which produces a burr on the edge. Since it’s only the burr that does the work, when the burr is worn off, the scraper is dull and the burr must be restored. Sometimes the burr may be lost in just a few seconds of cutting.

During sharpening, the burr forms on the top of the edge of the scraper because many of the abrasive particles have negative rake angles. Such particles tend to plough a groove through the steel without removing much of the material. The encounter with the negative rake particles on the top edge of the scraper deforms the steel at that point, producing a lip, which is the burr that does the cutting. This burr can also be produced with commercial burnishers for HSS scrapers.

The sharpening process for scrapers generates a lot of heat by deforming the steel. Be sure to use clean, dressed wheels when sharpening scrapers to keep heat buildup to a minimum.

It is easy to grind an old scraper to the shape or profile you want. Then grind the secondary bevel on the underside, which will leave a burr on the cutting edge (see Diagram C at right). This can be done with either HSS tools or carbon steel tools. However, keep in mind that the harder the steel, the longer the burr will last.

I do not recommend using old files for turning tools. They are too brittle and may fracture during use, possibly resulting in serious injury.

The benefits of using negative rake scraping only apply when using the scraper as a finishing tool where you are taking light, tissue-like shavings. A surface can be greatly improved using this technique; in fact, certain hard dense woods can be scraped to a glass-like surface, requiring little sanding. You must remember that this is not a technique for removing large amounts of wood and shaping turned pieces. Negative rake scrapers are a finishing tool!

Editor’s Note: See Stuart Batty’s website for additional information on negative rake scraping at www.negativerakescraping.com.