Every tool has its purpose: scrapers are for scraping, and gouges are for cutting. Some wood turners who are not so knowledgeable feel that scraping wood is not as high a calling as cutting–because it requires fine control to make a smooth surface with a gauge alone. When we scrape, we lightly touch the scraper tool to the spinning wood surface, and remove a fine shaving from the surface. Only a small amount of wood is removed with this procedure. Cutting, on the other hand, means presenting the cutting edge of a gouge on an angle so the tool slices deep into the wood, removing a small groove of wood as the lathe turns. With this procedure, much wood can be removed in a hurry.
Because of its nature, scraping is good for refining shapes, and smoothing out ridges left with gouges. The scraper is a flat piece of metal with a sharp, 90 degree angle edge which smooths the wood. The gouge, on the other hand, has a curved profile and leaves small ridges. The better you get with the gouge the less scraping you need to do, but even then the scraper may be indispensable for certain jobs. Because it removes such small fluffs of wood, it is great for making the ridges left by the gouge blend into one another.
What I have learned from trial and error is that the scraper works better on the base and outside of a bowl than it does on the side walls of the bowl. Used on the side walls (which are thinner and less stable when the lathe turns) there tends to be chatter of the tool, no matter now heavily it is constructed. This tool chatter with the scraper gives uneven cuts in the wall of the bowl that leaves a surface which is less desirable than when the gouge alone is used on the bowl wall. Hours and hours of sanding has driven this lesson home to me many times. Now I use the scraper on the base of the bowl inside and outside, and if I am careful, on the outside wall of the bowl–but at all costs I avoid using the scraper on the inside wall of the bowl.
Now, there may be a lot of individual variation here. Some wood turners may be so good with the gouge that there is little need for the scraper. Others may have learned to use the scraper where angels fear to tread. The point here is that you find out what works for you and others. Each tool does one function best, and the others may only do so so, or not at all. There are many hundreds of designs of lathe turning tools. They all came into being because they served a special function a little better.
But, it is best not to go overboard here. I already have so many turning tools that it is becoming hard to find the special tool I want in the ever growing stack of gouges, scrapers, and other specialized tools on my shavings-cluttered bench. One fellow at my turning club said he had over a hundred such tools. I can’t even imagine finding a special tool in all that clutter. Better to know how to get the most out of a few tools, than to have to reach for so many specialized ones. It saves time and resources.
The scrapers teach you patience and how to administer a light touch. Bear down on it and you get a nasty catch, or dig-in. Just take lighter and lighter cuts so what comes off the scraper is light fluff. Compared to cutting with gouges, it seems like the progress is very slow. Yet the time taken with very light strokes of the scraper is more than saved when it comes to sanding.
Everything is easy once you know how, but getting to that “know how” stage can be difficult. This is where practice comes in. Fortunately, wood tends to be a very forgiving medium. If you scrape too deeply, then you can gently, and gradually, just take more wood off, until you have a respectable surface.
It is like that in relationships too. Fortunately, like wood, people tend to be forgiving when we err, and we often get to make things right, without destroying the relationship. Yet, in our dealings with others, a gentle and light touch seems to produce the most satisfactory result. Heavy handedness takes much more effort to repair.