Sharpening high speed steel lathe tools

If a lot of force is being used to cut, then the skew needs to be sharpened. Spindle and bowl gouges along with the skew chisel will dull with time.

Several things cause the turning tools to become dull. The type of wood that is being turned can cause dullness pretty quickly.

Hardwood will dull out a turning gouge faster than softwood. The reason for this is the spindle and bowl gouges take a harder hit from hardwood. Which in turn knocks off the bur on the gouges faster, remember the bur is what does the cutting on both bowl and spindle gouges.

So what are some of the signs that your gouge has become dull? If the spindle or bowl gouge no longer produces quality shavings but instead produces chips then it may be time to visit the grinder to dress it back up.

Even though they are new you never know. The next thing to look for is do they have a bevel shape to them already? I hope all those that are new to woodturning have bought turning tools that are made from high speed steel or HSS for short.

HSS tools are better than lower grade steel tools for a few reasons. This also means less trips to the grinder to sharpen them. They also create less friction when sharpened or when doing actual turning. Before you can sharpen your chisels , you need to make sure the bevel and the angle is correct. The parting tool and skew chisel are probably the easiest turning tools to learn on. The parting tool has an angle of around 50 degrees. So all you have you to do is set your tool rest on the grinder up for a 50 degree angle grind.

Turn the grinder on and lower the tip of the parting tool onto the moving grinding wheel for a few seconds. Turn the parting tool over and do the opposite side for the same amount of time.

The end result should be the point of the parting tool be ground to a sharp squared of point. Shaping skew chisels are pretty easy to do as well. The angle for the skew is anywhere between 25 to 55 degrees. Like the parting tool set the tool rest of the bench grinder to the degree of what you want.

The first face to be cut was the side face. In this example we are making a normal right handed tool for the lathe. Grinding the side face of the tool. The grinding rest was tipped to give the required side clearance relief and the fence adjusted to give the side cutting edge angle. The work was fed across the edge of the grinding wheel with a light inward pressure to make the cut. The angle set by the table is the important angle here as is sets the side relief.

The angle of the fence is non-critical and is simply used so that the side relief doesn't have to be ground all the way along the tool. Second to be cut was the end face shown in green below. Grinding the end face of the tool. The grinding rest was tipped to give the required end relief angle and the fence adjusted to give the front cutting edge angle. The relief angle is the critical one. If the tool tip is to be radiused, it is cut next.

This can be done as a freehand operation on the bench grinder, or by hand on a grinding slip, if only a very small radius is needed. Grinding tool tip radius by hand. Finally the top face was cut. This face had a side and back rake angle. The completed tool. Images from metalartspress. Make sure your jig is tight against the guard of the bench grinder. Feed the bit forward slowly to make sure that it moves smoothly against the bench and has good contact. The actual grinding process is fairly straightforward, but there are a few things you need to remember.

Every ten seconds, cool the bit in a bucket of water. Another straight-forward step. Cool the bit before you move to the next face, and be careful not to over-grind any one face. Do your research, know the best angles for your tool and the appropriate metal, and use an angle jig to prevent mistakes.

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