Howdy,

I've only been lurking for  couple weeks, but figured it was time to
introduce myself: My name is Andy Birko, and judging from the "galoot
pattern baldness" on my left forearm, I think I would be kidding only
myself to claim I'm not at least part galoot (although I would consider
myself a reformed galoot due to the many tails in my shop).

I got (re-) interested in woodworking about 4 or 5 years ago to go along
with my cigar smoking hobby. Although I built plenty of balsa models as a
kid, I didn't really work with any harder woods until my first humidor
about 4 years ago.  After that, Normy fueled my lust for power.

After a few years of collecting apprentices (and hand tools, but mostly due
to economics, not desire) I read an article on sharpening in FWW...it
changed my life.  Once I figured out how to sharpen my chisels, I realized
that they weren't junk. Since then my collection has been growing.  For my
birthday, my wife picked me up an L-N # 2 and it fixed me for good.  I soon
learned that for the work I was doing I could either spend five minutes
with the sharp plane, or spend a day building a jig for my rapidly spinning
tool of the devil to do it in one second. Now, don't get me wrong, I still
use these devices, but as I alluded to before, my goal is to become a
renaissance woodworker, using the best technique for the job. I've
continued collecting and using hand tools (old and new, my latest being a
#606 in o.k. shape:  Plopped a Hock iron on it and it just melts the wood
away now) since my epiphany. In fact, on my latest project, a tool cabinet,
the only sandpaper I used is to sharpen irons to commemorate my learning to
turn a hook on a scraper.

Anyhow, two main reasons for this note. One:  For the past year, I've
turned my focus toward lutherie (if that term is not guitar specific). To
be specific, I build a Ukrainian instrument called the Bandura (for more
info, check out www.bandura.org, I'll have my own web site in a few weeks).
The bandura has a very large soundboard that's under a lot of stress.
Ideally, once strung, the soundboard should be flat.  An experienced
builder gave me the advice of making the soundboard slightly convex (like a
giant contact lens) so that it straightens out under tension.  On his
instruments, he makes the center of the soundboard about 2mm higher that
the edges....not much!  So I figure I can use either my block or #2 to
carve the convex part, but what about the concave part on the opposite
side?  (He also springs the underside bracing in addition to the carving)

Woodcraft is selling  a kakuri brand wooden block plane for $24.99. For
that price, I can experiment with making the sole convex to follow the
inner curve. Would this be the way to go, or will my regular block plane
suffice?

Topic number two:  Stanley #53? (I think it's a #53, I meant to bring the #
to work but forgot) spokeshave. This thing is a spokeshave with an
adjustable toe (for depth, kind of like a tailed planer). The thing works
just wonderfully and I was wondering if they're rare or something because
I've never seen another one.

Nice porch you guys have here.

-Andy Birko

Welcome, Andy! Yeah, the Porch is a great place...

you asked about the belly of a bandura:

> The bandura has a very large soundboard that's under a lot of stress.
> Ideally, once strung, the soundboard should be flat.  An experienced
> builder gave me the advice of making the soundboard slightly
> convex (like a
> giant contact lens) so that it straightens out under tension.  On his
> instruments, he makes the center of the soundboard about 2mm higher that
> the edges....not much!  So I figure I can use either my block or #2 to
> carve the convex part, but what about the concave part on the opposite
> side?  (He also springs the underside bracing in addition to the carving)
>
> Woodcraft is selling  a kakuri brand wooden block plane for $24.99. For
> that price, I can experiment with making the sole convex to follow the
> inner curve. Would this be the way to go, or will my regular block plane
> suffice?

A few weeks ago, BugBear gave us some formulas for planing something flat:

>switching symbols, where P is length of plane, B is length of board, S is
set of plane
G = S(B^2/P^2)

Switch this around to solve for the set required to produce the 'sag' you
want:

S = G(P^2/B^2)

Using a #9-1/2 block plane (which has a 6.25" sole length) and assuming that
the belly of the bandura is 2 feet long, to produce a .080" 'sag' (which is
roughly 2 mm) requires a set on your block plane of .005". Not unreasonable!

So the answer is, you should be able to plane the desired hollow with a
standard
block plane. Find some way to set the depth of cut to the desired value (one
way
is to set the plane on a fairly flat surface which won't damage the blade,
then
slide feeler gauges underneath the sole to check the amount of set).

Then plane the piece, but don't start at the end. Start with the sole of the
plane
fully on the piece, and stop planing before the sole leaves the workpiece.
When
the plane stops cutting, you will have achieve the desired hollow.

Hope this helps!

Kelly Cox
Madison, WI

Hi Andy,

Welcome to the porch.  Lots of fun to be had, lots of knowledge available,
and plenty of friendship, providing you stay on topic.  Otherwise, lots of
spittoon polishing.  Yup, I've polished my share of the brass.  (grin)

You asked:

(snippage, per FAQ)
> Topic number two:  Stanley #53? (I think it's a #53, I meant to bring the
#
> to work but forgot) spokeshave. The thing works
> just wonderfully and I was wondering if they're rare or something because
> I've never seen another one.

Not particularly rare, but not too common in my experience.  And you're
right, they work just great.  There is also the #54 which has straight
handles.

Hope that helps, at least a little.
Bruce Z.

Kelly Cox writes about planing a 2mm "sag" into the soundboard of a bandura:

[snip]

>Using a #9-1/2 block plane (which has a 6.25" sole length) and assuming
that
>the belly of the bandura is 2 feet long, to produce a .080" 'sag' (which is
>roughly 2 mm) requires a set on your block plane of .005". Not
unreasonable!
>
>So the answer is, you should be able to plane the desired hollow with a
>standard block plane.

In theory this would work, but I'm not sure if it would in practice (I
know-- in theory there's no difference b/w theory and practice ).  I
think a simpler and less error prone approach would be to rough this out
using a toothing plane and scraper.   I know this is/was a common lutherie
technique for other thin-stock applications, and it should work for this as
well.

If you're set on using a plane, the Stanley #100-1/2 (tiny squirrel-tail
block plane with a rounded bottom) would do nicely for roughing out the
cavity.  I'd still finish off with a scraper, though.

I use the toothing plane and scraper combo all the time-- it allows you to
remove stock very quickly, while still retaining the high degree of accuracy
needed for thin stock preparation.

ralph

Of course, you could also use the bandura soundboard as an
excuse to buy another tool! I'd go for one of those work-of-art
Laarman violin makers' planes.  ;->

What Ralph is proposing sounds a lot more sensible than my
approach (using a block plane). Although I typically plane a
piece hollow with a light set using the aforementioned technique
(to make sure that I'm not planing it convex) I don't typically
work with thin stock. Ralph, as the Porch's Shaker box expert,
does a lot of this sort of work.

Regards,

Kelly Cox
Madison, WI

Thanks for the advice. I was already figuring I'd be finishing up with a
scraper. I already have a French curve type of scraper, but figured one
with a more gradual arc would probably work better.  And now to demonstrate
my severe ignorance:  What is and where can I procure a toothing plane?

-Andy

***************

In theory this would work, but I'm not sure if it would in practice (I
know-- in theory there's no difference b/w theory and practice ).  I
think a simpler and less error prone approach would be to rough this out
using a toothing plane and scraper.   I know this is/was a common lutherie
technique for other thin-stock applications, and it should work for this as
well.

If you're set on using a plane, the Stanley #100-1/2 (tiny squirrel-tail
block plane with a rounded bottom) would do nicely for roughing out the
cavity.  I'd still finish off with a scraper, though.

I use the toothing plane and scraper combo all the time-- it allows you to
remove stock very quickly, while still retaining the high degree of
accuracy
needed for thin stock preparation.

ralph