My mahogany dagger board was damaged when I bought the boat used. I glued
it with epoxy and put some fiberglass around it and it has held up for a few
years, but I don't think it will last.

I bought some 8/4 white oak on ebay for almost nothing (100bf for $1.25),
and figured I will build a new daggerboard while I had something intact to
copy.

The blank is 44" long, 2" thick, and 15" wide. It weights 35 pounds.
I originally intended to cut the corners off on my table saw, but it is so
heavy that it doesn't seem particularly safe.
So, I have been going at it with my 3" belt sander and my 2" power planer.
Both would work, but they would take hours and hours of work.

Any suggestions for a good way to shape my blank into an airfoil shape?
I am thinking of buying a better planer, but hope someone here will be
resourceful.

On Thu, 15 Sep 2005 22:11:16 GMT, "Toller" wrote:

snip
Any suggestions for a good way to shape my blank into an airfoil shape?
I am thinking of buying a better planer, but hope someone here will be
resourceful.


Google for "naca airfoils"
Regards,

Bruce Nichol
Talon Computer Services
ALBURY NSW Australia

http://www.taloncs.com.au

If it ain't broke, fix it until it is....

I assume you have the old board to use for a pattern of the cross section.

I know that white oak would be difficult to shape by hand plane or any of
the power tools you mention.

For my 3" thick plywood rudder, I use a 4" disk grinder fitted with a
special wood carving wheel. This is a steel disk with chain saw teeth on
it's edge. Very aggressive cutting, so go slow and careful..

The PacNW wood carvers use these along with their regular chainsaw tip to
carve detailed statues.

Just rough out your board shape and finish with the plane or belt sander.


--
My experience and opinion, FWIW
--
Steve
s/v Good Intentions

"Toller" wrote in message
...
The blank is 44" long, 2" thick, and 15" wide. It weights 35 pounds.
I originally intended to cut the corners off on my table saw, but it is so
heavy that it doesn't seem particularly safe.
So, I have been going at it with my 3" belt sander and my 2" power
planer.
Both would work, but they would take hours and hours of work.

Any suggestions for a good way to shape my blank into an airfoil shape?
I am thinking of buying a better planer, but hope someone here will be
resourceful.

I'd go for the power planer. A good one can take away 1.5mm (1/16") in one
stroke, which means you can take away half of the thinkness of your blank in
16 strokes.

Meindert

Toller wrote:
My mahogany dagger board was damaged when I bought the boat used. I glued
it with epoxy and put some fiberglass around it and it has held up for a few
years, but I don't think it will last.

I bought some 8/4 white oak on ebay for almost nothing (100bf for $1.25),
and figured I will build a new daggerboard while I had something intact to
copy.

The blank is 44" long, 2" thick, and 15" wide. It weights 35 pounds.
I originally intended to cut the corners off on my table saw, but it is so
heavy that it doesn't seem particularly safe.
So, I have been going at it with my 3" belt sander and my 2" power planer.
Both would work, but they would take hours and hours of work.

Any suggestions for a good way to shape my blank into an airfoil shape?
I am thinking of buying a better planer, but hope someone here will be
resourceful.


Use your table saw as a shaper by sliding the blank sideways over
the blade. It will leave concavities, a hollow ground shape you can
refine more easily. A well made slide jig should provide a reagulare
shape and remove most of the unwanted material.

Don't be afraid to drill a few bolt holes in your saw top to hold
special jigs, or use eccentrics to hold in guide slides.

Cut strips to sit in grooves able to slide, lay ply on top, pin with
brads, screw together from other side. with saw, route grooves the
other way, make side slider jig. Screw on a fence to enable milling.
Terry K

You can make transverse saw cuts and take out the wood with a chisel. Then
clean up with a plane or whatever. Dont' go all the way in with the saw
because the wood will not cut out smoothly. Practice on scrap first.
If you can figure out some way to do it with a power saw it allows you to
set the depth of cut.
--
------------------------------------------------------------------------------
William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-FreeNet email must have "notspam" in subject or it's returned

You can make transverse saw cuts and take out the wood with a chisel. Then
clean up with a plane or whatever.

That's an interesting idea that none of the woodworker I spoke to thought
of.
I will try it out on some scrap.

"Toller" writes:

snip

I bought some 8/4 white oak on ebay for almost nothing (100bf for $1.25),
and figured I will build a new daggerboard while I had something intact to
copy.

The blank is 44" long, 2" thick, and 15" wide. It weights 35 pounds.

Question: Is this a massive plank or quarter-sawn strips glued together?
If it is a massive plank you should count on it warping.

I originally intended to cut the corners off on my table saw, but it is so
heavy that it doesn't seem particularly safe.
So, I have been going at it with my 3" belt sander and my 2" power planer.
Both would work, but they would take hours and hours of work.

Any suggestions for a good way to shape my blank into an airfoil shape?
I am thinking of buying a better planer, but hope someone here will be
resourceful.

This is probably the wrong answer but I actually mean this:
Use the oak for something else. Buy some light wood like Western Red
Cedar and shape a board. Add unidirectional carbon for bending
stiffness and strenght. Sheat in glass-epoxy and paint.

A WRC blank should be light enough to handle on the table saw.
Cut grooves to a depth that just 'touches' the future profile.
Use a power plane to remove material almost down to the future
profile and then continue with a hand plane and long board sanding.

Have someone calculate how much carbon you need and then use a
router to cut out some material from the WRC board so you can add
the carbon without ruining your profile.

More on boards at:
http://hem.bredband.net/b262106/Boat/dagger.html

--
================================================== ======================
Martin Schöön

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
================================================== ======================

I'd go with Martin's recommendation of materials. A white oak board, while
maybe stable, will be too heavy to handle.
Google for a NACA foil design program.
For shaping it, I'd use a router as the shaping tool. Make a slotted
'bridge' which will guide a router over the victim. The bridge can run
either the long way or cross-ways. If the bridge runs the long way, it can
be straight but rest on curved templates at the ends of the board. If the
short way, the bridge must be curved, but it will run on straight guides at
the edge of the board. I'd favor the short curved bridge, which will flex
less.
"Schöön Martin" wrote in message
...
"Toller" writes:

snip

I bought some 8/4 white oak on ebay for almost nothing (100bf for
$1.25),
and figured I will build a new daggerboard while I had something intact
to
copy.

The blank is 44" long, 2" thick, and 15" wide. It weights 35 pounds.

Question: Is this a massive plank or quarter-sawn strips glued together?
If it is a massive plank you should count on it warping.

I originally intended to cut the corners off on my table saw, but it is
so
heavy that it doesn't seem particularly safe.
So, I have been going at it with my 3" belt sander and my 2" power
planer.
Both would work, but they would take hours and hours of work.

Any suggestions for a good way to shape my blank into an airfoil shape?
I am thinking of buying a better planer, but hope someone here will be
resourceful.

This is probably the wrong answer but I actually mean this:
Use the oak for something else. Buy some light wood like Western Red
Cedar and shape a board. Add unidirectional carbon for bending
stiffness and strenght. Sheat in glass-epoxy and paint.

A WRC blank should be light enough to handle on the table saw.
Cut grooves to a depth that just 'touches' the future profile.
Use a power plane to remove material almost down to the future
profile and then continue with a hand plane and long board sanding.

Have someone calculate how much carbon you need and then use a
router to cut out some material from the WRC board so you can add
the carbon without ruining your profile.

More on boards at:
http://hem.bredband.net/b262106/Boat/dagger.html

--
================================================== ======================
Martin Schöön

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
================================================== ======================

Question: Is this a massive plank or quarter-sawn strips glued together?
If it is a massive plank you should count on it warping.

It is two pieces (both 2" thick) glued together. I don't need it until next
spring. I can get it close, leave it for a few months, and then finish it.
Would that help?

This is probably the wrong answer but I actually mean this:
Use the oak for something else. Buy some light wood like Western Red
Cedar and shape a board. Add unidirectional carbon for bending
stiffness and strenght. Sheat in glass-epoxy and paint.

Oak is about 50% heavier than mahogany, but I actually want the weight, so
that is not a problem. Besides, it is free and the cedar would be about
$50.