On Apr 16, 3:19 pm, rjdankert wrote:
Hi, I think this is my first post here. I have been lurking here for
a little more than a year when I bought my first lathe. It is a mini
(10 inch). I have one of Raffan's books, have taken several turning
books out of the library, been to many websites (Around the Woods is
my favorite), and don't have a clue how to search this group for ruts
in concave turning. On concave pieces - plates and bowls I get "ruts"
on the inside surfaces after using a bowl gouge. I've only turned one
green bowl and everything else was with dried wood. I am using a
Benjamins Best bowl gouge with the grind it came with. I've turned
cross grain and crotch pieces so far. What I end up with are what look
like ruts in the bottom. I also have trouble with the nubbin in the
center. It dosen't come off cleanly - sometimes leaving an
indentation.. I eventually get the ruts out with a round nose scraper
and sandpaper. .It seems to take forever.

I am hoping that someone might recongize these "symptoms" and provide
some advice

TIA,

Bob

Hello Bob,

I'm not sure what grind the Benjamins Best bowl gouge has on it, but
my experience says that most bowl gouges from the factory do not have
a good grind on them. If the gouge happens to be a 5/8" shaft, I would
recommend purchasing the Ellsworth Grinding Jig and put the Ellsworth
grind on your gouge. This gives you a nose bevel angle of somewhere
between 60 and 65 degrees and good swept back wings. This particular
grind will allow you to cut from the rim to the center of the bottom
of the bowl in one smooth pass. Normal, factory ground bowl gouges
will not let you do this. Unless you have the Ellsworth Grind or a
very similar one, you will need two grinds on your gouge to cover the
area from rim to center. A gouge with a 45 degree nose angle will cut
smoothly about 2/3 of the way down the side of the inside of the bowl.
You then need a gouge with an angle of between 60 degrees and 70
degrees to continue on to the center of the bowl bottom.

With the Ellsworth grind, you can cut from rim all of the way to the
center, including removing that little nubbin at the center if you
finish your cut exactly on center. When you get close to the bottom
center, the wood is moving very slow so you must move your gouge very
slow and smoothly to avoid tearing out the center point and having a
detent instead of a nubbin.

The ridges you are talking about generally come from moving the tool
to quickly and not moving it smoothly. I think that most of this will
all be eliminated with a well ground bowl gouge and lots of practice.
When it comes to good woodturning, nothing beats making lots of
shavings; i.e., practice, practice, practice!!!

Welcome to woodturning and good luck with your turnings. As others
have said, the last resort is the 80 grit gouge, which also leave
grooves in the wood. I can remember when I started turning many years
ago, that the 40 grit gouge came in quite handy to start to smooth the
bottom of the bowl.

Some other reference material are videos and DVD's on turning and
three US magazines devoted to woodturning: American Woodturner
published by the American Association of Woodturners, More Woodturning
published my me, and Woodturning Design published by one of the large
publishing companies.

Fred Holder
www.morewoodturning.net