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GAS MECHANICAL
Converting
the Bachmann On30Davenport
into
a Deutz Inspired Gas Mechanical
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Inspiration/Concept |
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The
Bachmann Davenport gas some very easily identifiable
characteristics, that always show themselves and make the origins
of any "bash" done with them easily identifiable, and
often odd in appearance. The worst of these offending items are
the frame, and the wheels/weights, wheel spacing and side-rods.
Since I
wanted to make this a fairly easy and and quick build/conversion
that anyone could easily do, I chose to primarily address the
frame, and let the wheel/side-rods remain as they are.
I began
this project without any drawings or plan of attack. I merely did
some web research to find images of numerous small Deutz locos
&. some general dimensions. Once I felt I had a good enough
idea of what I wanted, I disassembled the Bachman loco, clamped
the frame into the mill, and began cutting away, till it looked
like what would be right for the end result.
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| CONSTRUCTION |
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All the
milling was very quick and basic, and done using a small table-top
mill. The most complex cut was the one shown below , where I had
to rig up a Rube Goldberg style clamping set-up to mill .030"
off the rear pilot beam.
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following three image show the milled frame.
Material
was removed from the top and underside to create a more plausible
deck plate thickness. The overall deck was milled narrower, as
were the end sills on both ends.
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A view
showing the material cut away from the underside of the deck, and
the rear end sill (the small raised area around the notch is to
maintain enough thickness/integrity for the wall of the screw hole
that holds the rear coupler box).
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| Once
the frame was done an initial rough elevation drawing of the loco
to see scale and proportion. The determining factor was once again
the frame, and also the existing bonnet part. Since the Bachmann
frame is almost a scale 3' shorter from what would be needed for a
true Deutz loco, and the wheel spacing is far to close,
proportions needed to be squeezed, compacted, and played with
somewhat. (Basically, if one squints real hard, it could possibly
pass for some kind of Deutz.)
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| After
receiving some additional dimensional information from fellow
model-builder Frank Tavernier, this drawing was later revised
somewhat (bonnet raised & moved forward, cab roof lowered), to
somewhat more closely resemble the proportions of some of the
smaller Deutz locos.
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| The
original Bachmann bonnet piece with all the raised detail removed,
stack hole filled, detail line filled, and sides extended. Though
not very Deutz-like, in the spirit of simplification, I chose to
leave the cast-on radiator grille detail, and reuse the Bachmann
headlight assembly (hence not filling the 3 holes in the top)
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| Here
you can clearly see some more of the rework that was done to the
original Bachmann piece:
1. the
sides were extended using .040 x .125 styrene strip
2. The
front was also extended .125", but thicker styrene was used
in order to "push" the bonnet further forward on the
frame.
3. The
original Bachmann mounting tab was cleanly cut from the original
part, and re-attached on the inside of the thicker styrene
extension.
4. the
rear of the original bonnet piece was removed, and a piece of
styrene reinforcing was installed.
5. Slots
were cut in the side at the locations where the ventilation holes
are to be in the new side panel.
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above image shows the reworked bonnet area test fitted on the
frame. Here you can see how much closer the bonnet now sits
towards the front.
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| FMW
is Foothill Model Works http://www.foothillmodelworks.com/index.html
They can be found on the “Detail Parts” page…about halfway
down. I have had outstanding service and quality from them.
The only
modifications done to the stock coupler were to drill out/enlarge
the existing pin hole (to .045”) to accept the new larger pin,
and to lightly sand the face, so that it was
smooth/vertical….the stock one has just the slightest vertical
rounding (as per the prototype it represents)…so that there
would be no gap between the coupler face and the new piece of
.020” (.6mm) styrene. Since the coupler is styrene, liquid
solvent was used to attach the styrene to the coupler.
Note…it helps to pre-bend/arc the styrene piece, prior to
applying.
The
coupler box is the one that comes on the Bmann Davenport…merely
stripped of paint and a new .045” hole drilled through from top
to bottom so as to accept a PSC pin.
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rolled edge at the cab walls was done using a continuous .030
styrene rod, set flush/tangent to the interior side. Each section
of the wall was glued separately, then left to fully cure, while
held in place with some Tamiya masking tape, before the rod was
bent, and attached to the next section. (The small blob of putty
seen on in the corner above was due to the application of too much
pressure on the plastic rod with the tweezers, while bending. This
caused an indentation/divot in the rod which required some
filling/repair.)
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| .023"
dia. rivets were punched from .010" styrene using the Waldron
micro-punch and die set. Once cured, a Micro-Mark fiberglass
pencil was run over them to ease the top edges. (To give a more
arced top appearance.)
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| I
finally couldn't take the Bmann counterweights anymore, so I used
a Dremel tool with cutting bit, to grind them off, and give them a
more realistic appearance..
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Painting |
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