Hi Colin the groove is on the top of the tool on all three tools. I use this style on softer materials aluminium or EN1A steel for instance to get a good finnish and the third style I would use that as a roughing out tool for the same as the top groove acts as a chip breaker as well.

David

Might be wrong but I've always assumed the groove to be a chip-breaker. It's purpose is to snap the long spirals of swarf that otherwise get entangled or form clumps. Chips are easier to clear than spirals.

A swarf ball catapulted by the chuck once hit me hard enough in the face to draw blood. Since then I wear eye protection and clear swarf before it builds up.

Dave

I like the look of the groove cut into these tools,, I wonder if one could cut the same with a worn angle grinder disc may be worth a try?

Regard Bee.M

If a tool is to cut properly, it needs to be mounted so that the cutting edge is on centre height.

A slight radius on the cutting edge will improve surface finish, but must extend down the edge to ensure that only the point contacts the work, to prevent the lower part of the tool rubbing.

With regard to describing the hand of the tool, when the tool is mounted, if the edge points towards the chuck, to cut, it is a Right Hand Tool A Left hand Tool faces towards the Tailstock.

Think of it as if you are looking on the point of the tool from the other side of the lathe.

One of my hobby horses is to advise making a Centre Height Gauge, to which tools can be set.

If the tool is on centre height, it should cut well and not produce a pip when facing the end of a bar.

It is easy to make, a good learning exercise, and a saver of time, and frustration in the future.

Somewhere among my albums, there is a picture of the one that I use.

The important thing is ensure the column and base are perpendicular to another. Holding the column in the chuck, and just skimming the base is the easy way of achieving this.

Howard