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This topic seems to come up periodically
and we hope that it will be helpful to add some additional information,
about our instruments, to the discussion. In general, there have been
three types of neck joints used for instrument construction: the dovetail,
the mortise and tenon and the bolt-on. The reinforced mortise and tenon
neck joint that we use has not really been discussed but is often,
incorrectly, associated with bolt-on necks or other types of mortise and
tenon joints.
The dovetail and the mortise and tenon
are fitted and glued joints when used on mandolins. They maximize surface
contact between the neck and the body of the instrument and they are very
stable joints, when done well. After the glue dries, they are not
adjustable or easily replaced. True bolt-on necks are very different.
They are not designed to be glued. A bolt-on neck may be removed or
replaced by simply taking out the bolts and lifting the neck off.
When we started Sound To Earth, Ltd. we
were not locked into any specific tradition. We could choose or invent
whatever design elements we felt were best for our instruments. Most of
us have worked with other neck joints in the past (I was responsible for
adjusting the equipment that cut guitar dovetails at a previous job) and
we prefer the structural strength and simplicity of the reinforced mortise
and tenon joint that we designed and use. Our neck joint gives our
instruments a tight, strong, and stable fit at the heel and body with very
consistent neck angles on all three relevant planes.
The tenon is a simple rectangle the
height of our ribs and extension block (1 3/4 inches tall), nearly an inch
long and a 1/2 inch thick. The matching mortise is also a simple
rectangle. It has very large wood-to-wood contact areas and we get a
strong glued joint, on six matching surfaces (four sides of the tendon and
two wings that transition the neck to the body), that has its greatest
structural strength perpendicular to the force of the strings. The large
height and length of the tenon also gives the joint good resistance to
lateral and twisting forces. The screws, that we use, go through the head
block and into barrel nut inserts in the tenon. The style of insert and
the way that they are placed is unique to our “WEBER” instruments. They
clamp the neck against the body until the glue dries and give mechanical
support to the joint after the glue has set. Since two of the three
relevant neck angles are determined by two vertical cuts, perpendicular to
the body and parallel to the center-line of the instrument, we really only
have to focus our adjustments on the primary neck angle. We use two
screws so that we can do fairly minute adjustments to that neck angle
before the glue dries. All of the design parameters of our mandolin body
are dependent on these neck angles. The top graduations; brace
dimensions; and bridge height are optimized to our specific angle. If
that angle varies from our intended specifications the tonal qualities of
our instruments will be changed and we don’t like that. The mortise and
tenon joint is ideal for keeping these angles consistent, from instrument
to instrument, and that consistency is a primary reason that we use this
style of joint. We also like the very tight fit that we get from the heel
of the neck to the body of the instrument.
We do not believe that the mass or the
weight of the screws will have any affect on the tone or balance of our
instruments. The screws and inserts weigh less than 1/2 ounce. Our necks
(peghead, veneer, tuners and fret board) can vary in weight as much as 3/4
of an ounce - with a typical weight being 16 ounces. Wood is wood and the
weight and density of it changes from piece to piece. With the average
weight of our mandolins being 32 ounces, the screws represent an
imperceptible fraction of the weight of the instrument. They are also
located very near the actual center of balance of the instrument so their
effect on the instruments balance is even further reduced. The shape of
the neck and peghead; the type of tuners, and the style of tailpiece will
have a noticeable effect on the balance and weight of the instrument. Our
screws will not.
We
feel that our reinforced mortise and tenon joint has many inherent
advantages for our instruments and our customers and that it should not be
misunderstood or confused with other neck joints.
Thanks,
Vern Brekke,
Sound To Earth, Ltd.
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Mor·tise also Mor·tice
\'mort-әs\
n: a hole cut in a piece of wood into which another piece fits to
form a joint.
Ten·on \'ten-әn\
n: the shaped end of one piece of wood that fits into the hole in
another piece and thus joins the two pieces together. |
