Model Construction

By Staff
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1. Paul Breisch 187 W. Ridge Pike Royersford, PA 19468
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2. Coles' Power Models
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3. Ed Chick 5210 6th Street Winona, MN 55987 Fuller Johnson Model
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4. De Bolt Machine
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5. Shelly's Model Shop
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6.J.C. Whitney & Co. 1917-19 Archer Ave.
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2114 Alamance Church Road Greensboro, NC 27406

Many of you will remember the back cover of the August 1987 GEM
showing models of the Fuller Johnson engines. Since the magazine
came out, there have been inquiries from persons throughout the
States wanting information on the casting kits for building those
kinds of models. After answering numerous letters and telephone
calls about the source of the casting kits, maybe it would be good
to mention the names and addresses of casting kit suppliers from
which I have ordered materials. Please refer to a listing at the
end of this article. Please refer also to April 1987 GEM, page 28,
listing model kits and suppliers of that date.

The photos shown on the back cover of August 1987 GEM were made
in January 1987. Since that time a headless Witte (De bolt
Castings) and two more Fuller Johnsons (Ed Chick’s Castings)
have been completed. Quite a number of questions have been asked
about various machining and construction details, so a few photos
were made of these last two Fuller Johnsons to illustrate my ideas
for machining and building.

The crankshaft is fashioned from a rectangular cold rolled steel
(CRS) bar. (photo No. 1) The selected bar is covered with layout
ink (By Kem Blue) and the two centers scribed on the ends of the
bar and the entire profile of the crankshaft is scribed on one
side. The scribing gives visual guidelines for removing all
unwanted metal. As much metal as possible is removed with a band
saw and the remainder is turned on a lathe with the ‘throw’
portion being completed first. As the picture shows, one end of the
crankshaft is ‘finish’ turned then reversed end for end
between centers and supported by a steady rest before the other end
is completed. An ‘oilite’ bronze bushing is held by the
steady rest to allow accurate alignment of the shaft. As the second
end is turned the bending of the shaft due to tool pressure is
greatly reduced resulting in a more accurate turned crankshaft.

The next several pictures show the model in various stages as
assembly progressed. As the pictures show, all painting and stiping
is done before assembly begins. After machining, each casting is
smoothed by grinding, hand filing, and sanding as necessary to
remove uneven surfaces and parting lines left by the foundry
process. All holes or voids and any abrupt changes in surface
contour are filled with automobile body filler and sanded smooth.
All oils which were used for drilling and tapping are removed by
washing the castings with denatured alcohol. Machined mating parts
and casting surfaces, drilled and tapped holes, and all functional
bores are masked using masking tape. To prepare the metal surface
to receive the final paint, all surfaces are primed with gray
primer paint (Rust-Oleum or De Rusto), two coats minimum. About
twenty-four hours of drying time is allowed between coats. This
material is readily available at most hardware stores. Next follows
three coats of a chosen enamel paint. Again Rust-Oleum or De Rusto
is a good choice. A small one-inch paint brush works very good.
Spraying is not necessary to produce a great-looking paint job.

After the paint has dried for about a week, decorating by hand
painting, pen striping and various designs can be painted onto the
enamel surfaces. This is the ideal time to apply designs since the
parts are accessible on all surfaces. Painting is much more
permanent than adhesive-backed pen stripes. You need not be an
artist since ‘air brushes’ and ‘striping rollers’
(see reference 6 for catalogue) are available. For those persons
who are artists the regular striping brush does a beautiful job. If
an error is made in the decorating immediately remove it with a
cloth soaked in gasoline and start over. The gasoline will
evaporate leaving a clean surface to try again. All the decorating
on the engines shown was done with a ‘striping roller’ and
spray stencils and an ‘air brush’. Now for the ideal way to
decorate an engine is to have an artistic wife to paint for you as
Betty Duggins of Winston Salem, North Carolina does for her husband
Henry. They have truly beautiful equipment when engine showing time
comes. By the way, Henry and his son Mike build most of their
exquisite models without the benefit of castings.

The brass castings are completely filed and sanded after
machining, before buffing with rouge (see photos 2 and 4). The sand
cast surfaces are filed flat using a medium cut file. One hundred
and fifty grit sandpaper is used, then followed with 220 grit. Each
time a different grit is used the scratches left by the previous
treatment must be completely removed. Since most of the cast
surfaces are irregular in shape, this is a hand type operation.
Many hours are spent in preparing the brass to give the final
buffed shiny surface. All of the other brass parts shown are first
machined and then given the same hand treatment as the
castings.

The Fuller Johnson’s gasoline tank goes into the base. Brass
again makes a very attractive container and the base casting can be
machined with recesses to retain the gasoline tank to make the
mounting brackets invisible from the outside (see photo 3). A check
valve is needed between the gasoline tank and the carburetor. Start
with a brass 1/8‘ NPT X 90 degree angle
to ?’ ferrule tubing fitting, (find at hardware store or
plumbing store); turn a seat from brass for the O.D. to press fit
into the hole below the shoulder of the ferrule portion of the
fitting. Using a #47 drill pierce the seat and complete one side
using a 1/8‘ Dia. ball end mill, machine
to about 0.040 depth. After press fitting this part into the
purchased fitting complete by adding a
1/8‘ Dia. brass or stainless steel ball
(see Lee Pedersen’s advertisements in GEM for the balls). An
adaptor of brass will also be necessary to go from ?’ tubing
size to 1/8‘ tubing for the connector
between the gasoline tank and carburetor. This takes more time than
using a plastic tubing but is also more permanent and looks very
nice. All the brass parts are polished and buffed before
assembly.

The gears are standard stock items from gear manufacturers. In
this area there are several suppliers among which are Boston Gear
Works and Martin Gear Company. There are three important items to
remember in order to select the proper gear pair; these are: pitch
of the gears, center to center distances, and the number of teeth.
On any 4 cycle gasoline engine, there are twice as many teeth on
the cam gear as there are on the crank-shaft gear. The reason for
this is the crankshaft must make two complete revolutions each time
the cam gear turns one time. For all castings kits worked on to
this date, the center to center distance of the gears are already
established and a boss is provided in the base frame to accomodate
the respective shafts.

When gears are considered different from those specified on the
drawings, other factors must be considered such as face width, hub
dia. and extension, and bore sizes. To make sure the gears look
more like the original cast type of the full size engines holes or
slots can be added as desired by the individual (see photo No. 4
showing the cam gear). Usually the standard stock gears are cheaper
in price than the customized gears specified on the drawings.

The Fuller Johnson and the Witte engines were both bored to a
2′ dia. and standard Briggs and Stratton piston rings P/N
290290 were used. Valves for the Fuller Johnson engine are Briggs
and Stratton P/N 23386 modified by cutting the stem to length and
threading. Valves for the Witte were turned from CRS bar stock.

Wooden bases are constructed to one’s own liking. For the
models shown, material for the base of the Witte and one Fuller
Johnson is white oak while that of the other Fuller Johnson is
black walnut. The shapes are band sawed to pattern and hand sanded
to smoothness. The handle ends, which are round, were formed by
using a spoke shave and sandpaper. After all construction is
completed 5 coates of urethane varnish will give the wood
protection from all elements including gasoline and motor oil.

The wooden base as can be seen in photo No.5 is constructed to
accommodate all of the electrical ignition components. A standard
on/off switch from Radio Shack, a 12 volt automobile ignition coil
and a 6 volt square lantern battery is used to supply the voltage
to the ignitor. Wire is #22  AWG stranded, and the two ends
which terminate on the battery are equipped with alligator clips.
These two wires are approximately 2 feet in length so they can be
connected to an external battery if desired, either 6 volt or 12
volt. The battery case is a discarded 20 ounce soup can. The
battery and coiled-up lead wires fit very nicely into the can. The
can is mounted on a 3 degree angle so every-thing will remain in
place as the engine vibrates during running. A push-on type wire
termination is provided at the ground terminal and on the ignitor.
This allows easy removal when the ignitor is disassembled for
cleaning the contact points.

The battery and coil box for the Witte was built using box
joints. These can certainly be made using the table saw or router,
but have you ever thought of using the milling machine? Just cut
the four sides to the proper lengths, clamp all four together in
the vertical position, and mill 0.250′ width slots through all
the pieces. Move the table 0.500′ and continue this pattern.
The corners of your battery and coil box will fit perfectly.
Splintering of the cuts can be prevented by adding a scrap of
1/8‘ masonite to each of the two outside
faces of the wood when they are clamped for milling.

The ignitor housing is made of yellow brass, sanded, buffed and
polished. The two mounting bolts are 1/4
hex head brass made so they can easily be removed using a
?’  ‘spintite’ wrench. The ignitor will require
being removed every day or two and cleaning the points by brushing
with a small wire brush to remove carbon. The carbon will build up
because the slow speed at which the engine runs does not develop
enough heat to burn the carbon away. The contact points of the
ignitor are machined from a 1/8‘ diameter
welding rod. This material is soft and a good electrical
conductor.

All parts of the carburetor except the metering adjusting needle
are machined from yellow brass (as shown in photo #6). Fittings for
the gasoline connection are machined to mate with standard
1/8‘ diameter ferrule tubing fittings.
The seat for the metering adjusting screw is made per the drawings
and drilled with a #60 drill. The screw thread portion is machined
and drilled to accept a 0.040 diameter sewing needle. This needle
is cut to desired length and coated with ‘loctite’ sealant
#290 and pressed into the thread portion of the adjusting screw.
The sewing needle has a very gradual taper and will allow metering
adjustments to be made which are not oversensitive as many of the
pointed screw ends turn out to be.

There are new model kits appearing each year. One of these was
demonstrated this past August at the Portland, Indiana Show. At the
present time, two of these stovepipe Domestic side shaft engines
are under construction. Please refer to listing #5 at the end of
this article for model information on this kit.

Acknowledgement: The ‘good’ photographs were made by
professional photographer Mr. Whitey Boswell of Greensboro, North
Carolina. The remaining attempts at pictures were made by me.

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