SPRING POLE LATHE TOOL CHOICES
When I first became interested in spring pole lathes I assumed that I would simply use the same tools that I used everyday on my powered lathe. I remember reading that a spring pole lathe was “safer” than a powered lathe due to its lower operating speed. Well, it turns out that due to amount of torque generated and the fact that a spring pole lathe is a reciprocating tool, I’ve re-thought my tool selection. Perhaps I can save some novice pole turners some frustration by sharing a few thoughts about some tools that I find useful when using my lathe.
Understanding the “Catch”
Most turners use the word “catch” to describe the moment in which a shearing tool, more often than not the skew chisel, decides to take off, seemingly of its own accord, and leave a deep diagonal line across the face of the work. This, invariably, happens when the surface is nearly complete, necessitating an unexpected “design change”. This phenomena might better be referred to as a “chase” or “skate” as it is created when the cutting edge has an insufficient clearance angle. The workpiece literally drives the tool which acts like a threadchaser. Due to the high torque of the spring pole lathe, a “skate” can happen very easily.
Rolling beads with a skew is the mark of a skilled turner. That said, the fact that you are presenting a cutting edge that is diagonally positioned to the rotation of the work is “flirting with disaster”. The skew chisel will remain the best finishing tool, bar none. However, when rolling beads on a high torque, reciprocating lathe, there may be other options that will make life a little easier. The first is the beading and parting tool. It is simply a narrow, double-edged chisel. It is simply presented perpendicular to the workpiece axis, then rolled in either direction to form the bead. The finish left by the tool is quite good as the double bevel burnishes the surface as the cut is made.
A second option for rolling beads is the bedan. It is similar in size to the beading tool. However, it is a single bevel tool. This means that the cutting edge is ground at a steeper angle than the beading tool. “Bedan afficinados” will typically work the bedan in an “upside down” manner, meaning bevel up. I becomes a very agressive shaping tool when used in this manner. The surface finish created when using the bedan in this manner is rather “open” and may required a little additional burnishing or sanding. Using the bedan with the bevel down yields a nicely burnished finish. The steeper cutting angle will require some adjustment. The turner may find that a “bevel down” bedan offers a somewhat better finish when turning figured workpieces.
Gouges – Shallow is good
For me, a shallow gouge and a perpendicular presentation seem to work best on the spring pole lathe for creating longer or varying radius curves. The classic “English” grind or a shallow “Ladyfinger” work especially well. That said, I’ll frequently use a very exaggerated detail gouge for rolling convex, as well as concave surfaces. With gouges, like straight or skewed chisels, the turner must be aware of the cutting and presentation angles.