How can one judge the thickness of the timber when turning a vase with thin
sides.

Derek
Basically, you measure the wall thickness. For this you need calipers or a
laser thicknessing device. The easiest caliper is made from a piece of thick
wire and bent into a circular form. If you know the ends are 1" apart for
instance and the with the end of the wire inside the vase touching the wall
leaves a 1/2" gap between the outer wall and the other end of the wire, you
know the wall is 1" - 1/2" = 1/2" thick. There is an example on my web site
under hollow turning.

--
God bless and safe turning
Darrell Feltmate
Truro, NS Canada
www.aroundthewoods.com

Darrell Feltmate is right, as usual, about a quickie way to check thickness.
Somewhere or another (too long ago to remember) I found a cheap regular
caliper with the tips pointed inward. The advantage is that you can not
only get a clear measure of thickness at a particular point, you can also
use it to see if you have reasonable consistency up and down, which is often
my problem.

Bob Moody

On Thu, 14 Apr 2005 17:29:40 GMT, "derek smith"
wrote:

How can one judge the thickness of the timber when turning a vase with thin
sides.

It depends what you call "thin" but if it is thin enough, you can
shine a light through it and use that to get a consistent thickness.
This works with most woods but translucence does differ for different
woods and also depends on moisture content. You can either shine from
the inside out or vice-versa and peer through the opening to see how
much light is penetrating.

Try it with a scrap piece first to give you an idea of how it would
work with whatever wood you are using.

Other ways are to use calipers, thumb and finger ( if you can get to
where you're trying to measure!) or plain guesswork which may be
improved with feeling the weight of the vase, although you probably
don't want to keep taking the piece off the lathe to see how heavy it
is.

Cheers

Paul
www.hannaby.com
replace spamtrap with rcwmail for email replies

When using translucency for judging wall thickness, you must also
realize that, typically, the sapwood will transmit more light than
heartwood and that light is transmitted more easily through end grain
than side grain. So, just knowing the amount of transmitted light is
not enough -- it takes some experience.

There are lots of technologies being used for doing thin hollow forms.
Some folks use not much more than the feel of the work and the sound and
a bit of Zen -- knowing where the cutting tip is by visualizing what
cannot be seen. One of the masters of this way of working is John
Jordan. John also hand holds his tools where as many of us use a
trapped boring bar system.

You need a good catalog to see what is available -- I suggest that you
get on Packard Woodworking's mailing list. The Jamieson system and many
others much like it are available for doing the boring and all offer
add-on laser systems for gauging wall thickness. If you are handy you
can probably make one of these systems yourself.

Bill

Paul wrote:
On Thu, 14 Apr 2005 17:29:40 GMT, "derek smith"
wrote:


How can one judge the thickness of the timber when turning a vase with thin
sides.


It depends what you call "thin" but if it is thin enough, you can
shine a light through it and use that to get a consistent thickness.
This works with most woods but translucence does differ for different
woods and also depends on moisture content. You can either shine from
the inside out or vice-versa and peer through the opening to see how
much light is penetrating.
....snip

Paul
www.hannaby.com

I've debated the lase rigs for a while. Building one would be
interesting. Most of them are sold with extra supports ie gates to help
hold everything steady. However, I've never felt the need for the extra
support and I've done a bunch of hollow forms over the past year.

I did some checking and found that most of the laser holders run around
$150. Anyone have plans for the rig? I'm using the kelton hollower.

Bill Rubenstein wrote:
When using translucency for judging wall thickness, you must also
realize that, typically, the sapwood will transmit more light than
heartwood and that light is transmitted more easily through end grain
than side grain. So, just knowing the amount of transmitted light is
not enough -- it takes some experience.

There are lots of technologies being used for doing thin hollow forms.
Some folks use not much more than the feel of the work and the sound and
a bit of Zen -- knowing where the cutting tip is by visualizing what
cannot be seen. One of the masters of this way of working is John
Jordan. John also hand holds his tools where as many of us use a
trapped boring bar system.

You need a good catalog to see what is available -- I suggest that you
get on Packard Woodworking's mailing list. The Jamieson system and many
others much like it are available for doing the boring and all offer
add-on laser systems for gauging wall thickness. If you are handy you
can probably make one of these systems yourself.

Bill

Paul wrote:

On Thu, 14 Apr 2005 17:29:40 GMT, "derek smith"
wrote:


How can one judge the thickness of the timber when turning a vase
with thin
sides.


It depends what you call "thin" but if it is thin enough, you can
shine a light through it and use that to get a consistent thickness.
This works with most woods but translucence does differ for different
woods and also depends on moisture content. You can either shine from
the inside out or vice-versa and peer through the opening to see how
much light is penetrating.

...snip


Paul
www.hannaby.com

The laser systems only work properly if your cutter is at or near the
spindle height and if the laser is close to directly above the cutter.
So, using a laser without a trap system ain't going to get you nowhere,
I think.

Building your own is a piece of cake. There have been articles for both
traps and laser systems in the AAW journal(I think that publication of
the idea originally can be found here) and I suspect that a Google
search will turn up more. I remember one system which used tubing
bought from a boat supply place. My rig was originally home made -- the
boring bar, the trap and the laser rig. I am now using a commercial
system but there is a story here which I haven't decided to tell yet.

BTW, I weld which helps increase my list of options.

Bill


william kossack wrote:
I've debated the lase rigs for a while. Building one would be
interesting. Most of them are sold with extra supports ie gates to help
hold everything steady. However, I've never felt the need for the extra
support and I've done a bunch of hollow forms over the past year.

I did some checking and found that most of the laser holders run around
$150. Anyone have plans for the rig? I'm using the kelton hollower.

Bill Rubenstein wrote:

When using translucency for judging wall thickness, you must also
realize that, typically, the sapwood will transmit more light than
heartwood and that light is transmitted more easily through end grain
than side grain. So, just knowing the amount of transmitted light is
not enough -- it takes some experience.

There are lots of technologies being used for doing thin hollow forms.
Some folks use not much more than the feel of the work and the sound
and a bit of Zen -- knowing where the cutting tip is by visualizing
what cannot be seen. One of the masters of this way of working is
John Jordan. John also hand holds his tools where as many of us use a
trapped boring bar system.

You need a good catalog to see what is available -- I suggest that you
get on Packard Woodworking's mailing list. The Jamieson system and
many others much like it are available for doing the boring and all
offer add-on laser systems for gauging wall thickness. If you are
handy you can probably make one of these systems yourself.

Bill

Paul wrote:

On Thu, 14 Apr 2005 17:29:40 GMT, "derek smith"
wrote:


How can one judge the thickness of the timber when turning a vase
with thin
sides.


It depends what you call "thin" but if it is thin enough, you can
shine a light through it and use that to get a consistent thickness.
This works with most woods but translucence does differ for different
woods and also depends on moisture content. You can either shine from
the inside out or vice-versa and peer through the opening to see how
much light is penetrating.


...snip


Paul
www.hannaby.com

The original article on the use of a laser pointer to measure wall thickness was
published in More Woodturning. The article has been placed at the More
Woodturning web site at: http://www.fholder.com/Woodturning/article7.htm for
all to share.

The laser pointer must be located directly above the cutter and this can only be
done properly with a stabilized boring bar.

Fred Holder
http://www.fholder.com

In article , Bill Rubenstein
says...

The laser systems only work properly if your cutter is at or near the
spindle height and if the laser is close to directly above the cutter.
So, using a laser without a trap system ain't going to get you nowhere,
I think.

Building your own is a piece of cake. There have been articles for both
traps and laser systems in the AAW journal(I think that publication of
the idea originally can be found here) and I suspect that a Google
search will turn up more. I remember one system which used tubing
bought from a boat supply place. My rig was originally home made -- the
boring bar, the trap and the laser rig. I am now using a commercial
system but there is a story here which I haven't decided to tell yet.

BTW, I weld which helps increase my list of options.

Bill


william kossack wrote:
I've debated the lase rigs for a while. Building one would be
interesting. Most of them are sold with extra supports ie gates to help
hold everything steady. However, I've never felt the need for the extra
support and I've done a bunch of hollow forms over the past year.

I did some checking and found that most of the laser holders run around
$150. Anyone have plans for the rig? I'm using the kelton hollower.

Bill Rubenstein wrote:

When using translucency for judging wall thickness, you must also
realize that, typically, the sapwood will transmit more light than
heartwood and that light is transmitted more easily through end grain
than side grain. So, just knowing the amount of transmitted light is
not enough -- it takes some experience.

There are lots of technologies being used for doing thin hollow forms.
Some folks use not much more than the feel of the work and the sound
and a bit of Zen -- knowing where the cutting tip is by visualizing
what cannot be seen. One of the masters of this way of working is
John Jordan. John also hand holds his tools where as many of us use a
trapped boring bar system.

You need a good catalog to see what is available -- I suggest that you
get on Packard Woodworking's mailing list. The Jamieson system and
many others much like it are available for doing the boring and all
offer add-on laser systems for gauging wall thickness. If you are
handy you can probably make one of these systems yourself.

Bill

Paul wrote:

On Thu, 14 Apr 2005 17:29:40 GMT, "derek smith"
wrote:


How can one judge the thickness of the timber when turning a vase
with thin
sides.


It depends what you call "thin" but if it is thin enough, you can
shine a light through it and use that to get a consistent thickness.
This works with most woods but translucence does differ for different
woods and also depends on moisture content. You can either shine from
the inside out or vice-versa and peer through the opening to see how
much light is penetrating.


...snip


Paul
www.hannaby.com

On Sun, 17 Apr 2005 21:32:30 -0700, Bill Rubenstein wrote
(in message ):

My rig was originally home made -- the
boring bar, the trap and the laser rig. I am now using a commercial
system but there is a story here which I haven't decided to tell yet.


OOOooooo mysterious! c'mon tell!