Are there optimum techniques

[Mike Darlow]

Michael Anderson, thank you for your valuable insight. You are correct, my letter was written in answer to Terry Martin’s letter on page 8 of the June 2025 American Woodturner.

 

[Webb Willmott]

Most of my turning is kiln dried black walnut. What angle would you use?

 

[Mike Darlow]

Webb, 30 for roughing gouges and parting tools used to cut, and 25 for skews and detail gouges will be fine. The edges should however be honed. Please let us know how these angles compare with those you use now.

 

[Kevin Jenness]

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Hi Tim,
I grind on an 80-grit CBN wheel, then hone with the 600-grit diamond hone in contact with both the cutting edge and bevel heel to produce an effectively flat bevel. Your edges are coarser with hollow-ground bevels. Hollow-ground bevels if you're traversing in a straight line demand more clearance which is undesirable. Also because it's serrations are finer, my honed edge will last somewhat longer than yours.
If you hone, you can resharpen several times just by rehoning before having to regrind. This is quicker than having to reset your grinding jig to accommodate a tool change and then regrind.
The bowl gouges I use when hollowing all have convex bevels. I also use a ring tool. I always hollow outboard. When you have done so you'll never want to hollow inboard.
Best wishes, Mike Darlow

Why not just use a 600# wheel?

 

[Doug Rasmussen]

There is one definite optimum in cutters that do very well for bowls and spindles. That's the same exact cutter for both types of turnings. Also turns against the grain almost as cleanly as with the grain. And doesn't need any sharpening jigs, etc. Widely used in production and automated turning.

The cutter is a diamond shaped carbide insert with a small nose radius as shown below. These are high positive rake, razor sharp, mirror polished inserts with molded chip breaker originally designed for aluminum cutting. Given the small nose radius they sever wood fibers rather than pushing them away causing rough patches and/or catches.

having the high positive rake these cutters can tend to self feed sometimes so some means of dampening the tendency to self feed might be needed. Significant mass in the cutter holding mechanism is the best way.