I have heard that bead and cove joints can be used for mast/spar building.
Anyone ever done this?

--
Art Ransom
Lancaster , Texas

www.turningaround.org

On Mon, 5 Dec 2005 16:18:40 -0600, "Art Ransom"
wrote:

I have heard that bead and cove joints can be used for mast/spar building.
Anyone ever done this?


A similar, less labor intensive method is providing strips with one
fish mouth edge - 45 degrees, 90 degrees, 45 degrees.
The fish mouth fits the inner edge of the next strip.
All held together with hose clamps or tourniquets during glueing.
There is an optimal width/thickness for a mast diameter.
Search the web

Brian Whatcott Altus OK

That's the "Noble System" which was written up as "Bird's Mouth Hollow
Spars" by Aimé Ontario Fraser in Wooden Boat Magazine, July/August 1999

I've an expurgated version of the Wooden Boat article, with photos, that I
prepared if you'd like it. (Aimé spent too may words on social/dining
issues for my taste.) It's a huge file, 16 MBy, and of course it's
copyrighted material.

The scantlings given were, for an 8-sided spar:
Stave width: 0.4 x diameter of spar - taper square edge
Stave thickness: between 0.1 and 0.2 x spar diameter - (bigger for big
boats) (0.2 for spruce, 0.15 for Douglas Fir)

I think the scheme is also discussed near the back of Hassler/McCloud's
"Practical Junk Rig."

Roger

http://home.insightbb.com/~derbyrm

"Brian Whatcott" wrote in message
...
On Mon, 5 Dec 2005 16:18:40 -0600, "Art Ransom"
wrote:

I have heard that bead and cove joints can be used for mast/spar building.
Anyone ever done this?


A similar, less labor intensive method is providing strips with one
fish mouth edge - 45 degrees, 90 degrees, 45 degrees.
The fish mouth fits the inner edge of the next strip.
All held together with hose clamps or tourniquets during glueing.
There is an optimal width/thickness for a mast diameter.
Search the web

Brian Whatcott Altus OK

For me, the Herreshoff system of making a rectangular spar is so much
simpler and more likely to come out well that it is worth considering. A
rabit is made in the edges of the two side (cheek) pieces and the two other
pieces (fore and aft) fit into them.

"derbyrm" wrote in message
news:kcglf.624312$xm3.226764@attbi_s21...
That's the "Noble System" which was written up as "Bird's Mouth Hollow
Spars" by Aimé Ontario Fraser in Wooden Boat Magazine, July/August 1999

I've an expurgated version of the Wooden Boat article, with photos, that I
prepared if you'd like it. (Aimé spent too may words on social/dining
issues for my taste.) It's a huge file, 16 MBy, and of course it's
copyrighted material.

The scantlings given were, for an 8-sided spar:
Stave width: 0.4 x diameter of spar - taper square edge
Stave thickness: between 0.1 and 0.2 x spar diameter - (bigger for big
boats) (0.2 for spruce, 0.15 for Douglas Fir)

I found a few programs to calculate the dimensions. Although windows
applications, they're only 60kB large. I can mail them to anyone who's
interested.

Meindert

http://www.woodline.com/scripts/instructions.asp gives instructions on
how to do
this for varying numbers of strakes using their router bits.

Frank

Presently I am using the birdmouth and have used it with columns up to 16"
in diameter. I am interested in the bead and cove because it would give me
more flexibility in the number of staves.

--
Art Ransom
Lancaster , Texas

www.turningaround.org

I guess it would, but that flexibility comes with the loss of the
self-jigging features. If oval columns are acceptable, then go for it.

The router bits mentioned at http://www.woodline.com/Downloads/BIRDMOUTH.pdf
do provide for 6, 8, 12, and 16 sided columns.

Roger

http://home.insightbb.com/~derbyrm

"Art Ransom" wrote in message
. ..
Presently I am using the birdmouth and have used it with columns up to 16"
in diameter. I am interested in the bead and cove because it would give
me more flexibility in the number of staves.

--
Art Ransom
Lancaster , Texas

www.turningaround.org

On Wed, 07 Dec 2005 13:23:13 GMT, "derbyrm"
wrote:

I guess it would, but that flexibility comes with the loss of the
self-jigging features. If oval columns are acceptable, then go for it.

===============================

No reason for oval columns if you build around a form such as PVC pipe
or something similar.

"Art Ransom" wrote in message
. ..
Presently I am using the birdmouth and have used it with columns up to 16"
in diameter. I am interested in the bead and cove because it would give
me
more flexibility in the number of staves.

You can use the bird's mouth for any number of staves, you just need to
carefully calculate (or draw) the angle of the female part.

Tim W