bowl gouge nose angle ?

[Bill Bolen]

Over the last 7 or so years my bowl gouge nose angle seems to be changing. Most of my fingernail bowl gouges seem to have changed to about 60* or so with the bottom feeders at 70* + or - a bit. Just got a new D way 1/2" and it is 45* and I was surprised at the difference in position on the inside of bowls. Is the any advantage to the 45* angle inside? Smoother cutting less chatter ect.? I know the 60 to 70 degree angles make the transition fom side to bottom simplier by not getting interference from the bowl walls but what about the 45* angles advantages? Thanks for you opinions!

[Reed Gray]

Well, the theory, as explained by Stuart Batty, Chris Stott, and a few others is that the natural bevel angle of a beaver's tooth has evolved to be about 40 degrees, so that, because of evolution, is the ideal angle for most of what we turn and cut. I think they all work, and the most important thing is having a high shear angle (scraper flat on the tool rest is 0 shear angle, some gouges can so 45 or so, especially if you drop the handle, and a more ) nose profile like on Doug's fluteless gouge can easily to to 70 or higher. A lot of variables here. Just about any gouge can cut on the outside of the bowl. On the inside, more so if the form is deeper rather than shallow, you need one for the sides, and one for the transition and bottom of the bowl. If you don't have a 60 or steeper bevel angle, you can not keep the bevel on the wood as you go through the transition without your handle hitting the lathe bed, tool rest post, and bowl rim. You can do pretty much all of it with a 60 degree bevel. I do find it handy to use 2 gouges though. Does the 45 degree bevel cut any better? I don't know. Kind of like does the swept back gouge cut better than the fingernail gouge. They both work. More in how you present the cutting edge to the wood than the actual tool.

robo hippy

[John Keeton]

Bill, I am sure my grinds are the result of not having taken classes, no mentor, no club initially, and just grinding until it would work. In any event, I grind every gouge I have - spindle, detail, bowl - to 42*, with the exception of a Thompson 1/2" U, which is at 60* that I will use as a bottom feeder on those rare occasions I need one. Keep in mind that I rarely do bowls, and even then, I prefer shallow bowls - mostly of the ogee variety.

Over my three years of turning, I have used other's gouges, and the more acute angle I use does require a different presentation to the wood, but I have become use to it and it seems to work for me. It also greatly simplifies my sharpening! I have two slash marks on my Wolverine, but rarely use but the one.

This is from Doug Thompson's site, and is his suggestion as to grind angles - GRIND ANGLES.pdf

[Mark Levitski]

Bill, I think that Doug Thompson grinds his tools generically at one angle (pehaps the most commonly used angle) for convenience and because everyone will take his tools and do with them what serves them best. A lot of manufacturers expect that their "factory" grind will be toyed with and customized according to individual preferences. The exception is some of the signature tools/grinds that are purchased to find out exactly how the pros use their tools.

The major difference in nose angles is the postion of the handle as Robo said. There are a lot of people that put so much weight on the angle for sharpness. Sorry, I can't agree w/ that much of an emphasis. There is always a relief side to the edge of our gouge as it cuts. It is not at all like a wedge cutting into a piece of wood w/ no relief at all (in that case 40 degrees is probably better than 60). The cutting edge cuts and the chips eject on the angle of the flute side. I have never any difference at all with the sharpness of my 40 degree bowl gouge as compared to my 80. To me the jigs for setting the EXACT angle to sharpen are totally misleading people. That is not critical, except for what I said about the position of the handle.

Practically speaking, I find that my sharper angle bowl gouges are better for entry into a natural edge bowl. The point gets to enter before the wings so they do not more grossly and violently contact the bark. As the angle gets more acute, the wings get turned more and more away from the cut, and the angle of the transition from the point to the wing becomes more shear. Make sense? It's the reason that detail gouges can be as little as 35 degrees--to reach the nose into area without the wings getting involved.

[Bob Bergstrom]

Ok, if we go back before bowl gouges hit the scene, spindle gouges were held in a very vertical position on the rest. The wood was cut coming down the flute vertically. This position was held throughout the cutting of the interior of the bowl. Difficult to do! The early bowl gouges still had a fairly long bevel. It became the trend to arc the cut like the trajectory of a thrown baseball. The arcing allows a longer bevel to make the transition to the bottom of the bowl. The gouge does not slide on the rest, but becomes a pivot point. When done correctly, there is no tear out or rubbing of the heal on the surface of the wood. There can be problems with the ways. The steeper bevels along with more durable edges have allowed the technique to evolve to a much easier and versitle way. We are rid of bumping into the ways and the rim of the bowl. I think things like the CBN wheels, swept back flutes and carbide tips have change turning techniques on its ear.

[Harry Robinette]

I started turning with my gouges set to the angle they came from the factory. Sorby and Crown tools was all I bought and both were set at 45* for bowl gouges. I used them that way until I figured out that I needed my tools to do what I wanted them to do. Then I stared trying different angles for my tools,I turned for a couple months maybe a year with 45* and 50* to 55* and found that my cutting was getting much smoother and I could run a complete cut on the side of the bowl.About 4 years ago I changed to 60* on my bowl gouges and it changed everything for the better my cutting if a little better but my shear scraping and shear cutting has improved with the 60* nose, the wing is longer and with that the wing angle comes out perfect for me. Just my $.02

[Dennis Ford]

I like an angle of 40 - 45 deg for cutting green wood; it seems to cut easier and faster. A larger angle often works better on hard dry wood and the edge will last longer also.