Deep bowl inside final cut questions

[Keith Harrell]

I have been having some problems getting the last four(inside) or so passes on my bowls. I have been using a 1/2 bowl gouge with a 40 degree angle which works fine on all parts except the inside last 1/4 part towards the center.
I have been wondering if I get another bowl gouge and grind it to 55 degrees or so whether this would help. I don't have a scraper yet so this may also help I'm wondering. I use the fast grind jig from Packard which is like the oneway var-grind-2 jig.
If I get a scraper should I get a round tip 1".
Would it be best to grind both to a high degree angle.
Should I turn at a faster speed also. I have been using 750rpm now.
I have a Nova DVR XP
Only have been turning for six months so thanks

[alex carey]

I have a 1 1/2" scraper from BB and it works really nicely for the last part of turning a bowl. It is not as versatile as a 1" scraper but it is really heavy and makes a real clean cut.

[Dennis Ford]

Keith;
You are on the right track, a gouge ground with a more blunt angle will work better near the bottom of deep bowls. You will likely get multiple opinions about what angle to use. The 55 deg angle you mentioned up to about 65 deg should work.

You will eventually get a scraper also, some get that before the second gouge.

As to speed, there are several factors to consider:
* Stiffness and mass of the lathe, if the lathe is shaking, slow down.
* Strength of the bowl, hollow form etc, if the piece is thin, has voids or cracks you have to avoid blowing it up (centrifugal force).
* Diameter of the piece. There are some charts for this although the charts don't agree with each other.
* Your comfort level. Turn as fast as you are comfortable within the limits of the first two. Higher speeds will slightly improve the quality of the cut, but will not compensate for poor technique.

[Steve Schlumpf]

Keith - any chance you can post a photo or 2 of the problem area? Might help make suggestions a little more accurate.

[Mike Minto]

keith, i often use my sorby hollowmaster's round cutter to take finishing cuts on bowls. works pretty well, long as i keep it sharp! i also have a shop made tool with a hunter cutter; i like that for light, finishing cuts in bowls, too.

[John Beaver]

Don't forget the center of the bowl is spinning much slower then the outside.
Take very light cuts and take your time.

[Dave Rudy]

Keith,

The swept-back (irish grind, ellsworth grind, etc) bowl gouge doesn't work well on bowls unless they are extremely shallow.

A traditional grind bowl gouge works wonders. Sharpen even up to 70 degrees . It should take you through the lowest part of the side around the corner into the bottom and all the way to center.

Mike Mahoney uses one and you can see it in operation in any of his bowl videos. Tree to table and Heirloom are good examples.

[Ryan Baker]

The grind you need depends on how deep your bowl is. You have to be able to keep the bevel rubbing without hitting the side walls. A 40 degree grind won't be able to do that very often. I have a 5/8" U-shaped Thompson that is ground to 80-85 degrees, with no more than a degree or two of sweep back. It does wonders at cutting the bottoms of deep bowls and slices off end grain like butter. The large diameter gives it stiffness when it is hanging well over the tool rest working on the bottom of deep bowls. It's a very task-specific tool to be sure.

[Bernie Weishapl]

I use a 1/2" and 3/8" P & N gouges with a conventional grind and a bevel of 65 degrees,

[Radek Kowalski]

I turn my bowls with a V shape bowl gouge. I can get a nice cut but nothing I would consider final. For that I use a 1 1/4" inboard bowl scraper. The thing works wonders. I used to use a round nose but the difference is big for me between the two in the angles of the bowl.

[Keith Harrell]

The biggest problem was getting the bevel to ride and it wanting to really cut deep the closer to the center I got.
I'll grind down one of my gouges to be a inside gouge 65 deg or more so I'll work on that. I also ordered a 1" 1/4 scraper from Thompson. He was out of the 1" and it looks like I need to spend some time on the grinder when it comes in.
The goal was to spend less time using my 80 grid gouge to smooth the inside and get a smoother flow. Thanks
I assume I need to raise the tool rest to be above center when using the scraper.

[Rob Cunningham]

In Ellsworth's book, he recommends an 85* grind for deep bowl interior cuts. I have only tried the grind once but it seemed to work.

[Reed Gray]

I have a friend who took his Thompson scraper to a saw shop and they ground the profile for him very cheaply. Much more aggressive grinders and belts they have.

Getting a clean cut going from the wall through the transition to the bottom of a bowl is difficult. 45 degree bevels will work on shallower bowls, but on deeper ones, you can't make it through the transition area without coming off the bevel, and when you do that, you lose all control of the tool. Also, you can find the handle bumping into the edge of the bowl and the tool rest because you can't rotate it far enough to get through the transition. Solutions are a more blunt angle on your gouge, in the 60 degree range for normal bowls, and up to 80 degrees for deeper bowls, and/or a scraper. If you use a more blunt gouge, generally there is less sweep to the nose profile than on a swept back design, and less than a more normal fingernail gouge profile. You do not want square like a spindle roughing gouge as the corners will dig in. For the scraper, I will have it flat on the tool rest for roughing/scraping cuts, and at a 45 degree angle for finish/shear cuts. Do not take the scraping cut up to the rim of the bowl, it will bowl rim, which is thin, will vibrate like a soap bubble, and if you don't remove the tool quickly enough, you will get a big catch and explosion.

robo hippy

[Jake Helmboldt]

Keith, you might want to start with a light radius shape to the scraper like Raffan uses and modify it as you go rather than take a big chunk of metal off from the start.

As Reed mentioned you can get a nice finish shear scraping with it at an angle. When HD was blowing out their Oneway products I got their 1.5" heavy duty scraper and it has a domed or rounded end. The extra thickness and mass really leave a nice surface. I can get a pretty clean surface with the gouge, but not as smooth as with the scraper. Maybe with more practice?

[Denis Puland]

Hi
They say a picture is worth a thousand words so here a picture of my three bowl gouge grinds.

No. 1 is for the transition and across the bottom on deep bowls.

No 2 handles the same as no. 1 for medium to shallow bowls.

No. 3 Is primarily used for roughing and shaping the outside and the inside of straight walled bowls.

These grinds are done on home built gigs and a belt sander.

I am a self taught turner and probably have many bad habits and tecnech so take this with a grain of salt.

Denis