What's in a Lathe?

[Jon Rista]

If that "uneven waviness" is what I think it might be, I'd suspect a sharper tool would solve a lot of your frustration. I know, I know.....the subject of what is and isn't sharp is a very touchy subject to a lot of turners....even to those who have years of turning experience under their belt.

Most turners use an edge created from their slow-speed grinder and go directly from there to the lathe. Some will swear they have sharp tools, and even use words like "scary sharp" to describe their cutting edges.....but, I have my suspicions.

For myself, the grinder is nothing more than a tool that speeds up removing metal up to the edge, but does not create the cutting edge itself. My gouge cutting edges are all hand honed.....the modern diamond hones are the best at this task......but, even the old Arkansas honing stones will do just as well. My finest scraper burs are created with diamond hones on the top edge and then manually raised on a carbide post. (For general rough work, the scraper burs created on the grinder will suffice for that purpose.)

-o-

Added content: If you want the sharpest edges possible.....then be prepared to sharpen much more often than you ever thought you would, or should. It is these fine edges, when maintained, can and do produce the finest surface quality. When you reach that level of cutting edge maintenance, then you will make it possible to create surfaces direct from the tool that require a bare minimum of sanding.

I actually do sharpen a lot. Constantly. Especially when turning bowls, I sharpen many times for both the inside and the outside (unless its a small bowl, I guess.)

I have not, however, used a hone to fine tune the edge. I have CBN wheels, 350 and 600, and will use the 350 if I need to really re-grind the shape, and the 600 to get a finer edge. I don't know how the 600 grit CBN compares to a diamond hone though... I think I did try to hone in the past, but, my concern always was losing the angle of the edge vs. the bevel. I don't think I ever found anyone demonstrating how to properly hone a gouge back then, and just stuck with the grinding wheels. If there is a technique to properly honing a gouge, though, that wont' muck it all up, I'll happily give it a try.

 

[Jon Rista]

I am still aspiring to starting at 180.

I used to start at 180... But I found that was leaving scratch marks in my bowls, vases, etc. once I sanded up to 320 or 400. Even after more extensive sanding with 220 and 320, there were often scratches left by the 180 that I just couldn't get rid of, without going back to 180. I am not a hard sander, either, I use a pretty soft touch, and learned to sand at a speed slow enough that the sandpaper "grips" and then to let the grit do the work, and not use pressure (unless there was some serious tearout or something.) Starting at 220, I no longer have that issue. If I am lucky enough to get a pretty well-tooled surface (and I've learned a lot of techniques for that now...such as sheer scraping, using a negative rake scraper designed for the kind of grain and inside vs. outside, etc.) then I may even start at 320.

I haven't touched a piece of 60, 80, or 120 grit since early 2021 (I started turning the beginning of 2020). Late last year, I got back into turning things other than pens (which was all I really did from mid 2021 through mid 2023), and have hardly touched even 180 grit. I DO use it, when I end up with tearout that other grits just don't seem to correct, and then, only if I cannot first use a tool to correct the tearout (some woods, like this cottonwood I'm working with now, just...seem to tear out so easily, and even with careful tooling, sometimes the only way to completely get rid of the remnant is sanding... :'( ).

I think the keys that got me to this point, were learning how to properly sheer scrape (something I think I only learned properly after watching a Jimmy Clewes video on turning a platter). Proper sheer scraping required re-sharpening the tools so it was extremely sharp, keeping it that sharp until you were done with your sheer scraping, and also keeping the angle of the cutting edge VERY high, so that there was really only a glancing of the surface to peel off these super fine shavings. That has honestly been one of the best tools for me, to produce a super clean tooled surface, that doesn't need too much sanding. It is not as good, I don't think, as tooling well enough with a proper finishing cut using the gouge normally...but, I can't seem to figure that out, so I'm still not able to get those "perfect" geometries...at least, I don't know how with a sheer cut. Sometiems I can still faintly feel peaks and valleys, and if I try to fully correct them with a sheer cut, then I am often bound to create other issues. But anyway, its a good way to clean up your wood surface so that you don't have to start at say 60 grit!