Lathe Speed Question
 

Greetings and Salutations:

I am fairly new to the world of woodturning. Lathe speeds for spindle
turning I have pretty much figured out. But when it comes to turning bowls I
would like to know what speed the lathe should be set at when using the bowl
gauge? The first time I tried to use this tool I almost destroyed the piece
I was working on when I started shaping the bowl.

Any help would be appreciated.

Steven Raphael ( Happily turning goblets and cups )

Lathe Speed Question
 

Steven

If you are afraid of having the piece explode on you while it is spinning,
then it is going too fast. Anytime you do not feel comforatble with the
lathe's speed is a good indication that it is too fast. If you approach a
piece and it is going too slow, then kick it up to the next level, it is
easier to start slow and go up than it is to start fast and go down -
because the piece may not be on the lathe anymore once you start it too
fast.

Ray


"Steven Raphael" wrote in message
...
Greetings and Salutations:

I am fairly new to the world of woodturning. Lathe speeds for spindle
turning I have pretty much figured out. But when it comes to turning bowls
I
would like to know what speed the lathe should be set at when using the
bowl
gauge? The first time I tried to use this tool I almost destroyed the
piece
I was working on when I started shaping the bowl.

Any help would be appreciated.

Steven Raphael ( Happily turning goblets and cups )

Lathe Speed Question
 

The slower the better; especially when roughing out and when things start
getting thin.

For roughing simple bowls under 10" and when they are very well
balanced/rounded already, I'll start around 800 rpm. I'll drop down to 500
rpm if it's not rounded or well balanced. I'll drop down to 300 rpm if I
"feel" that it's too fast.

For roughing simple bowls in the 12" to 16" range, I'll start around 300 rpm
if they are well balanced/rounded. Again, I drop down if I feel it's too
fast for the given piece.

After roughing, I'll pick up the speed a couple of hundred rpm if I feel
it's safe. I might finish a simple 10" bowl at around 1000 rpm and then
drop down some to sand.

Now, all of those figures above are MINE. They need not be yours or anyone
elses. Sometimes I go slower (when in doubt go slower and build up speed if
need be) and sometimes I go faster. It just depends. When I first started
out, I was quite concerned with actual numbers of rpms, etc. Now, I don't
worry about it or even think of it. I go with feeling and how the
lathe/turning/tools are reacting. But that just comes with experience.

I used to rough out fresh-from-the-chainsaw 12" bowls at around 1000 rpm
because that was the slowest that lathe would run. It worked but I now know
that it was too fast for what I was trying to do. I might be able to do
that now fairly safely because I know more what I'm doing but I'm now wise
enough to know I shouldn't do it. g

Frankly, from your description below, I suspect that speed isn't the
problem per your "first time I tried to use this tool" statement. Tool
technique (presentation, position, type of cut, grind, depth of cut, etc.)
is far more important in your case, I think. Even at 100 rpm or slower,
poor tool technique will blow up a bowl too. Assuming you have the bowl
safely and securely attached by whatever method you choose, a good, proper
cut trumps the speed ... up to a point, of course. g Slow the speed down
to where it seems too slow (if you can) and work on the tool technique.
That could be your next question? You'll slowly speed up as you get more
comfortable with the tool and type of turning.


- Andrew


"Steven Raphael" wrote in message
...
Greetings and Salutations:

I am fairly new to the world of woodturning. Lathe speeds for spindle
turning I have pretty much figured out. But when it comes to turning bowls
I
would like to know what speed the lathe should be set at when using the
bowl
gauge? The first time I tried to use this tool I almost destroyed the
piece
I was working on when I started shaping the bowl.

Any help would be appreciated.

Steven Raphael ( Happily turning goblets and cups )

Lathe Speed Question
 

What Ray said, but with one more thought. Energy equals mass times the
square of velocity. You double the revs, you have four times the energy
available to bash your gouge into the wood.

Hey, I carve as fast as I can push a tool through wood with Armstrong power,
can't require a lot of turns to give the piece the same push if I'm holding
the tool steady.

"Steven Raphael" wrote in message
...
Greetings and Salutations:

I am fairly new to the world of woodturning. Lathe speeds for spindle
turning I have pretty much figured out. But when it comes to turning bowls
I
would like to know what speed the lathe should be set at when using the
bowl
gauge? The first time I tried to use this tool I almost destroyed the
piece
I was working on when I started shaping the bowl.

Any help would be appreciated.

Steven Raphael ( Happily turning goblets and cups )

Lathe Speed Question
 

"Ray Sandusky" skrev i melding
...

If you approach a
piece and it is going too slow, then kick it up to the next level, it is
easier to start slow and go up than it is to start fast and go down -
because the piece may not be on the lathe anymore once you start it too
fast.


This seems to be a good piece of general advice:

Start slower, and increase as you feel the need.

If you do not feel the need of higher speed, it's fast enough!

Bjarte

Lathe Speed Question
 

It may sound slightly contrary to some of the other advice, but you can
generally cut better at a slightly higher speed so that you are getting a
reasonable number of cuts per minute. If it seems to be going
bump-pause-bump-pause then speed up the lathe slightly (to a point below
what causes the lathe to shake) so it seems to go bump-bump-bump as you cut.

In case you didn't know, the flute of the gouge should also be horizontal to
45 degrees up, not pointed straight up. Then, rub the bevel along the wood.

Lathe Speed Question
 

Steven,

Here is a link to a lathe RPM chart that I have used as a rule of thumb (which
means that I only use it when it suits me):
http://www.turnedwood.com/LatheRPM.htm

Kevin Neelley
http://www.turnedwood.com

In article , Steven Raphael says...

Greetings and Salutations:

I am fairly new to the world of woodturning. Lathe speeds for spindle
turning I have pretty much figured out. But when it comes to turning bowls I
would like to know what speed the lathe should be set at when using the bowl
gauge? The first time I tried to use this tool I almost destroyed the piece
I was working on when I started shaping the bowl.

Any help would be appreciated.

Steven Raphael ( Happily turning goblets and cups )

Lathe Speed Question
 

Cuts per minute? You are referring to the air/wood type cuts you can get
hollowing when the piece distorts and you can't keep the edge in constant
contact with the piece?

If so, you're just changing to a different resonant frequency when
increasing speed. Making smaller chatter marks, basically. I think the
bowl steady the kids got me a couple years ago is great for this situation.
Even though the bowl may distort after you're finished, the walls remain
uniform in thickness, and you maintain a cut throughout, and don't get that
upgrain tearing you can get when the piece is squashing longitudinally. You
can start sanding finer, for a shorter time, and even cut thinner without
great risk, if that's your thing. Helps with "hollow forms" too.

Hey, fathers' day is coming.

"Derek Hartzell" wrote in message
...
It may sound slightly contrary to some of the other advice, but you can
generally cut better at a slightly higher speed so that you are getting a
reasonable number of cuts per minute. If it seems to be going
bump-pause-bump-pause then speed up the lathe slightly (to a point below
what causes the lathe to shake) so it seems to go bump-bump-bump as you
cut.

In case you didn't know, the flute of the gouge should also be horizontal
to
45 degrees up, not pointed straight up. Then, rub the bevel along the
wood.

Lathe Speed Question
 

Actually I am talking about when you start turning a piece before it is
round and smooth and you are still hitting corners. Steven said he had the
problem when he started shaping. If you have a lathe that goes down to 50
rpm and you try cutting at that speed when you start a 12" bowl, you will
have more problem with jerking and will be spending a lot more time on an
out-of-round item than if you start at 250-400 rpm.

Derek

"George" george@least wrote in message
...
Cuts per minute? You are referring to the air/wood type cuts you can get
hollowing when the piece distorts and you can't keep the edge in constant
contact with the piece?

Lathe Speed Question
 

There's also the question of what speed to use when sanding. At the rough
end eg 100 grit (well I admit to using it!) it doesn't matter much. However
when getting to 150 grit and finer, I need high speed towards the centre
becasue it's only moving quite slowly; howevre at teh periphery, when teh
speed is high, the heat generated by friction can crack the wood, hence I
slow it down. I find that purpleheart and pau amarello seem particulaly
prone to cracking.

Richard
www.shocks.clara.net/turning/index.htm
"Steven Raphael" wrote in message
...
Greetings and Salutations:

I am fairly new to the world of woodturning. Lathe speeds for spindle
turning I have pretty much figured out. But when it comes to turning bowls
I
would like to know what speed the lathe should be set at when using the
bowl
gauge? The first time I tried to use this tool I almost destroyed the
piece
I was working on when I started shaping the bowl.

Any help would be appreciated.

Steven Raphael ( Happily turning goblets and cups )

Lathe Speed Question
 

Wish I had a lathe that would go slower, but 500 is my low end. What I do
is cut from base, where I have a pretty flat area, outward and down ,
rounding bit by bit until I get to the rim. With the gouge at a skew angle
and supported firmly on the rest, where the wood is dragged down its edge as
I slowly advance, I can actually hog a big enough shaving to slow the lathe
through belt slip. So it's not normally a problem at 12" with mine, though
it can get exciting sometimes when I have a piece that's heavy one side,
like when I was turning some spruce that had been on the ground a while with
one side virtually dry, the other water-tossing wet. If you've got a lathe
with lots of torque, you can work lower speeds than one like mine which is a
3/4 induction-run belt drive, and has to rely on momentum.

No doubt about it, a tailstock is a necessity if you have an out-of-balance
piece.

Views at http://personalpages.tds.net/~upgeorge/basic_cuts.htm and
http://personalpages.tds.net/~upgeorge/pin%20one.htm
show my method. It's sort of by necessity and sort of by sense, as I cannot
reach to turn away from the headstock with a gap bed, and my old carving
teacher taught me that wood cuts more cleanly if you cut across and advance
simultaneously.

It's really the same technique for all interrupted turnings, cutting the
wood and letting the air take care of itself.

"Derek Hartzell" wrote in message
...
Actually I am talking about when you start turning a piece before it is
round and smooth and you are still hitting corners. Steven said he had
the
problem when he started shaping. If you have a lathe that goes down to 50
rpm and you try cutting at that speed when you start a 12" bowl, you will
have more problem with jerking and will be spending a lot more time on an
out-of-round item than if you start at 250-400 rpm.