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New S Scale Draft Gear Box

Closer-To-Scale

S Scale Draft Gear Box

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THE BAD NEWS :

S scale presently only has two sources for semi-realistic looking and operating couplers.  The first is Kadee Quality Products
which offers one coupler-and-gearbox in two different colors (the # 802 and # 808), and the second is S-Helper Service which also offers
only one coupler-and-gearbox in two colors (the # 01295 and the # 00588 (no photos available)); the #00588 coupler comes with a special
bracket for mounting on SHS' EMD F-Unit models.

Sergent Engineering once offered a much more realistic S scale coupler than what Kadee and SHS now offer, but it was taken out of
production a few years back when Sergent Engineering began re-tooling and refining their production methods of their better-selling
line of HO scale couplers.

THE GOOD NEWS :

Sergent Engineering has decided to release a new-and-improved version of their S scale coupler!  I have received three samples
of the PRE-production new S coupler for testing purposes, and have found them to be very reliable.  These couplers will be offered in
both kit form and RTR form.

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PILOT  MODEL  PHOTOS

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PROBLEM(S) :

The new Sergent Engineering couplers do not come with a gear box.  They will work fine in a standard Kadee 802/808 gear box,
but the Kadee gear box is much too wide for realistic appearance.  Also, Sergent couplers do not have a centering feature...
something that many modelers (myself included) prefer to have.

SOLUTION :

Design a new draft gear box that is more realistic in appearance and width.

Done.

CONCEPT :

Using a standard Kadee #802/808 gear box as a test platform, I cut and shaped a small block of white styrene to
fit inside the gear box behind the shank of the Sergent Engineering coupler.  I then cut some phosphor-bronze
strips to a length of just shy of the inner width as the Kadee gear box, and inserted it between the rear of the
Sergent coupler's shank and the shaped styrene block.  The idea was that the prosphor-bronze strip would press
against the flat rear surface of the coupler and force it to center.

It worked like a CHAMP!

Check out the photos and video below :

PROTOTYPE  PHOTOS  AND  VIDEO

Now just to re-size and re-shape the gear box to a more realistic appearance...

DESIGN DRAWINGS :

The drawings below show the finalized design of the first of my gear boxes.

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FINALIZED  DESIGN

Updated : 12 / 29 / 2013

Exploded Parts Drawing
2-D drawing showing parts of gear box

Exploded Parts Drawing (Color Coded)
Same as above with parts colored

Assembly Drawing
2-D drawing showing assembled gear box

Assembly Drawing Color Coded
Same as above with parts colored

Center Sill Extensions
Drawing showing extensions on back and sides of gear box that represent the car's center sills

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Back To S Scale Modeling Projects Page

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