Kenneth Michael Guitars est.1978
"Spartan Side Bending Machine"©  
The KMG “Spartan Series©” Side Bender Kit“ is a professional quality device that we
are offering at the modular level so that the hobby builder or small shop can afford
multiple units and the benefit of ready to run benders. While the “Fox Style” bender is
brilliant in concept, we have found that the change over time and the related
adjustments ultimately led to using most of our “Fox Style” machines for a single
pattern. The “Spartan Series©” Side Bender Kit” is designed so that it is economical,
easy to assemble and easy to use. We have incorporated some unique features that
speed loading and increase part quality.  The “waist clamp assembly” is a unique
laminated design to insure accuracy across the entire length. All bender styles are
equipped with aluminum “waist support bars”. While it may be possible to make gentle
bends without this feature, it made no sense to us to run the risk of possible warps and
cracked sides. Plus the support bar is an integral feature of our time saving pre-load
system. The wood components are precision machined to high tolerances made
possible with the use of our CNC machines.
The kit comes complete including
custom aluminum slats, the “Timer”
and all electrical panel wiring in done
for you. The reflective linings are
installed. You will need to purchase
three 200 watt light bulbs.  
The waist clamp swivels are fastened
to each side with three screws; the
swivel assembly is used to line up the
Four slat clamp stop screws are
positioned one at each end of the form
on both sides.
Fasten the loose “form panel” with one
screw into the base.
Fasten the “leg/ caps” to each end of
the base using four screws per end.
Fasten the slat clamp latch details to
the clamp bars using the ¾” pan head
Screw the 3/16” threaded rod into
each end of the waist support bar.
Assemble a ¼” threaded “L” bracket in each corner of the form, the
nut only needs to be finger tight.
Assemble the aluminum rods to the
Note that there is a top and a bottom
slat  -- the top slat is longer and has
detents on each end
A unique feature of the “Spartan
Bender©” are the waist locating
The large spring clamps provided are
used as a stand to assist in loading
and aligning the side, waist cauls, and
the top and bottom aluminum slat.
The “top slat” - “wood side”  - “bottom
slat” sandwich is placed and lined up
on the aluminum waist bar. Note that a
small notch is also made in the wood
side to mark the waist location.
The waist caul is placed on top the slat “sandwich” aligned with the waist marks
than, tighten the washers and wing nuts to secure the caul.
Place the caul/slat assembly on the
form locating the waist bar into the ¼
slot on the bender.
Position a threaded waist clamp swivel
on each side of the form and the waist
Push down on the waist clamp and
spin down the nuts.
In the dry run the nuts can easily be
turn down by hand  -- an open-end
wrench can be used with care. This
may be necessary with tight waisted
guitars like the 000 or J200.
The slat clamps have latches built on
the ends – place these in the open
The slat clamps are used to aide in
pushing the sides and slat around the
form. If this were for real we would be
wearing gloves.
Slip the threaded “L’s” into the clamp
slot then close the latch, the spring
action of the slats will hold the clamps
in position.
The wing nuts on the slat clamps are
turned down to complete the bending
action of the machine. Note the detents/
ledges on the ends of the top slat. This is
another unique “Spartan Bender” feature.
This allows the slats to be forced around
the form and firmly clamped in place. This
is an important function that is missing on
most other side benders. With out it the
side slips ups away from the form and
results in a soft or incorrect bend.
The KMG “Spartan Series©” Side Bender Kits“ are reasonably priced and available
in many popular styles.
Using the KMG "Spartan Series©” Side Bender"
First, lets put the guitar side bending process in perspective. Forget the
notion that you need giant springs, veneer press clamps or hydraulics -----
we are going to bend a piece of wood that is the same thickness as a
Popsicle stick! About .075 of an inch. What is needed is accurate alignment,
so the waist bend is in the right place and 90 degrees to the top edge of the
rim. The process requires relatively even heat distribution, gentle bending
pressure, and positive location until the bent side has cooled. The “Spartan
Series Side Bender©” offers all those attributes. We are not trying to crush
the wood into shape. The object is to make the wood pliable than gently
push it over the form. When at the correct temperature the side will present
very little resistance.
Three clear 200-watt light bulbs will generate plenty of heat. We have found that the
bender must be clamped to the bench. Working on the end of the bench works best.
A standard spray bottle works well for
misting the side and also testing the
temperature of the bender. When the
temperature is high enough a sprites
of water on the aluminum should
produce some hiss and steam.
A wood burning furnace thermometer
can be set near the waist clamp to
monitor the heat range. This may be
helpful in establishing precise operation
Prepare the side by marking the waist bend location. To aide in alignment use a file
and make a small notch on the top edge of the side. Than make a sandwich with the
aluminum slats aligning all the waist locators. A couple of small spring clamps help to
keep the layers lined up.
Slide the waist caul into place, line up
all the waist marks then tighten the
wing nuts. Make sure everything is
perpendicular with the top side edge of
the aluminum slats.
Set the "slat sandwich" on the bender;
place the aluminum support bar in the
waist slot. Position the waist “L” clamps
to the bender and the waist caul. Gently
push the support bar into the slot while
spinning down the nuts.
During the pre-heat stage the bottom aluminum slat is pulled down and held in
place with the slat clamps on both ends. It is not necessary to have them tight to
the bender. Also gently screw down the waist caul until resistance is felt. Closing
up the bender in this way will help capture the heat and speed the temperature
After about 20-30 minutes of preheat
the temperature should be high
enough to continue.  Spray a little
water on the bottom slat to hear the
steam hiss. If the heat is correct screw
the waist caul all the way down
Spin the wing nuts back and reposition
the slat clamps to the top side of the
slat sandwich. You should have at
least one glove on. With the glove
hand gently push the slats over the
form as you progress tighten the slat
clamp wing nuts.  Just before the final
tightening make sure the clamp
engages the detent on the top slat.
Push the clamp down to pull out any
slack in the bend – secure the wing
We perform the above procedure on the lower bout first; the logic is that the tighter
curve on the upper bout will have more time to heat up.  The upper bout is bent the
same way, work slowly and all will go well.
Set the timer for about 20 minutes to cook in the set. Do not remove the side until the
bender has completely cooled to room temperature.
Discontinued for DIY thought starters only