Duplex Standard Construction Toy

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Duplex Standard Construction Toy

Little Jim(1)
Steel Tech
Trumodel
Steel Engineering(2)

Duplex Standard Construction Toy was a development of the Erector construction system with alternate large and small holes for sale under stores own brand names. It was made in the USA from 1927 to 1932. It is believed to have been sold under the following brand names:-
Little Jim - by J.C. Penney Department Stores
Steel Tech - by Montgomery Ward & Co.
Trumodel - by Sears Roebuck (The Kelmet Corporation)
Steel Engineering - by an unknown company/store.

Initially, separate manuals were supplied for the various brand names. However later on in 1929 some manuals were issued without the relevant brand names. Presumably to save on costs.

Manufacturer / Distributor

The A.C. Gilbert Co., New Haven, Connecticut, USA

Info from the Metal Constructional Systems Database for DUPLEX STANDARD CONSTRUCTION TOY

Maker
Gilbert Erector

System Type
ERECTOR type

Country
USA

Dates
1929 to 1932

Material
Steel

Thread
8-32

Boss Type
single-tapped

Boss Thread
6-32

Diametrical Pitch of Gears
24

No. of Parts in System
207

Hole Pitch (Spacing) (mm)
12.7 (multiples of value shown, including half.)

Diameter of holes in Strips(mm)
4.4 (see comment *¹)

Diameter of the Bore in Bosses(mm)
4.1

Diameter of Axle Rods(mm)
4.0

Types of Nuts and Bolts
Nuts: square
Bolts: round (slotted)

Material/Finish of Nuts and Bolts
Steel with a Nickel plated finish

Size of the Nuts across Flats (mm)
6.4

Bolt diameter (mm)
7.2

Comments
Generic name of modified ERECTOR with alternate large & small holes in Strips, Plates. Sold by stores under brand names, see LITTLE JIM [1], STEEL-TECH, STEEL ENGINEERING [2, TRUMODEL. Data from LITTLE JIM set. *¹ & 6.6.

The MCS document for this system is shown below. It can also be downloaded to your computer if desired here

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Below there are manuals/leafets which can be downloaded by clicking on the appropriate image.

A Trumodel branded Duplex Standard Construction Toy manual for set 4 dated 1927.
(Added 20/01/2021)

An unbranded Duplex Standard Construction Toy manual for set 4 dated 1929.
(Added 23/05/2019)

A photo of the box lid of a Little Jim(1) set 1.
(Added 12/12/2020)