Powder Metal Gouges...
Hello Bernie,
What a nice problem to have (needing another bowl gouge)...
I've got about 35 different bowl gouges, in every metal alloy out there including M2 HSS, M4, ASP 2030, ASP 2060, A-10, A-11 and V-15. In addition, I have a huge selection of Cryogenically treated bowl gouges and lots of other Cryo tools as well.
The Crown Pro-PM gouges are very good, I have several and they do hold an edge much longer than standard M2 HSS. Since you are needing a 1/2" bowl gouge, this may be an excellent choice for you.
The Oneway M4 HHS double cut gouges are nice as well (I have three) and allow you to have two different grind profiles on each end. They hold and edge well and are versatile. One thing you may experience when working
long distances off the tool rest with this tool is a slight vibration in the gouge. Since the flute is ground so far up the shaft, there is very little solid metal left to help stiffen the gouge and prevent vibrations. If you have a curved tool rest, you can eliminate this problem by keeping your cutting edge fully supported throughout your sweep.
Cryogenically treated woodturning tools are getting a lot of buzz lately and are fine tools. I have been using cryogenically treated tools for several years, long before the major manufacturers offered them. I recently concluded a three and a half year study of cryogenically treated tools and published the results in my monthly woodturning newsletter "Lathe Talk".
My testing included standard M2 HSS tools, including bowl gouges and some carbide tipped carving tools. The M2 HSS bowl gouges averaged a 250% increase in edge life over the non-treated gouges. (For testing, I purchased two identical gouges, one was cryo treated, one was left as it came from the manufacturer - M2 HSS). I really like the cryo treated tools and use them frequently in my studio. Note: Some timbers averaged a higher edge life than 250%, but when all were averaged - highly abrasive and regular timbers, the end result was 250% better edge life.
If you want really good edge life, it's hard to beat the Glaser V-15 gouges. They are expensive, but they are amazing when turning abrasive timbers, or going through a lot of bark. They also work very well when turning "bad boys" like Australian Dead Finish, considered by many to be the most abrasive timber in the world. Its hard to come up with a favorite as all of these tools work well, but if I had to I would opt for the tools in this order:
Glaser V-15
Crown Pro-PM*
Cryo Treated*
The last two would be a toss up for a 1/2" bowl gouge. On other sizes, a clear winner would emerge. Good luck to you and best wishes in all of your woodturning endeavors!