I remember the halcyon days when M2 high speed steel (HSS) turning tools hit the market. No longer did we have to worry about burning at the grinder, and HSS tools held an edge forever — compared to plain carbon steel, anyway.
The last decade has seen a proliferation of turning tools made from exotic powdered steels. Powdered refers to the manufacturing process where iron, with the necessary alloying elements, is mechanically mixed in powder form, then sprayed into a furnace where the powders become plastic but do not melt. The resulting blob is cold worked to form bars for machining. Powdered metal technology allows much higher amounts of alloying metals such as vanadium (which increases edge holding) than conventional blast furnace manufacture. The price of such special handling is significantly higher, but PM steels give extraordinarily longer tool life for metal cutting.
I have long suspected that the metal cutting claims were accurate but did not hold true when cutting wood. In fact, for spindle turning, I feel a good old M2 gouge may hold an edge longer than PM tools. I am speaking from gut experience for I am fortunate to have tried about every new tool on the market. A second factor is that a new turner is going to grind up a tool or two in the “learning to sharpen” process so, for your first couple of tools, the grinder is the enemy and the cheaper the better!
A study James T. Stanley did with his engineering students at North Carolina State University at Raleigh in 2008 confirms my intuitive reaction. Those wanting to read this fascinating paper, can download it here. The study does confirm improvement in edge holding of PM tools when cutting wood but nowhere near the claims for metalworking. For bowl turners who know how to sharpen, the extra price may be salient.
I feel spindle turners are better off with M2 as it takes a keener, burr-free edge more readily. For scrapers, which are used by both spindle and faceplate turners, M2 is vastly superior to carbon or PM steel. Sorry to steal the PM thunder, but that is the way I see it, and I hope I have saved you a buck along the way.