Erector Classic Period Steam Shovel

Welcome to another "Complete Model" pictorial. This time, the subject is the very first of the so-called "Classic Period Models," the Steam Shovel. Gilbert first introduced this model in 1924, and it remained a staple in the Erector line until the end of the Classic Period in 1932.

BACKGROUND
Like the White Truck which came after it, the design of the Steam Shovel evolved over its lifespan. This pictorial is based on the original design, which appeared in Erector manuals from 1924-27. It was more complicated than the design that replaced it in 1928, and more difficult to build, but it featured more action as a result.

No. 7 Steam Shovel
Figure 1. Classic Period Steam Shovel

THE NO. 7 ERECTOR SET
In 1924, Gilbert kicked off the Classic Period of Erector by introducing specialty parts to the Erector inventory that were designed to build a specific model, in this case the Steam Shovel. He packaged these parts in the set designated the No. 7, which would eventually come to be known as the "Steam Shovel Set" by fans and collectors.

The 1926 version of the Steam Shovel is featured in this pictorial. Called the "Super No. 7 Erector," it came packed in an attractive, stained and varnished wooden box with brass sidegrips and latches. The box measures 21½" x 8½" x 3¼", and fully packed it weighs a little over 13 pounds. The parts are packed in two layers, the top layer being a cardboard tray. The manual of instructions included with the set features the No. 10 Coal Loader model on its cover, as did all of the Classic Period manuals.


Figures 2a-c. 1926 "Super No. 7"

MANUAL & MODEL INSTRUCTIONS
The instructions provided for the Steam Shovel in the 1926 manual were limited to two pages (see below) showing right and left-side views, and a picture of the wheel assembly, or "truck." While not the most complex design Gilbert ever created, it is the feature model in the manual, and is definitely complicated enough to have warranted several detail views (this is true of many Erector models over the years). A variation on this design, not shown here, is also included in the manual.


Figures 3a-c. 1926 Manual and Steam Shovel Pages

SPECIAL PARTS
As previously mentioned, special parts were created specifically for use in building the Steam Shovel. There were nine parts in all, including three new parts (plus one old one) to build the digger scoop. Of the nine special parts, four would gain widepsread use in other models over the years, and each one became a staple in the Erector inventory: the T boiler, U boiler top, W boiler stack, and BN turret plate. All nine special parts are shown in the image below.


Figure 4. Special Steam Shovel Parts

MODEL CONSTRUCTION
As the images in this pictorial indicate, the model is made up of three main subsections: the cab, truck, and boom/digger scoop assembly. The boom is fixed to the cab, and the entire cab/boom combination rotates freely on the wheeled truck beneath it. A P58 motor provides power to the digger scoop, which raises and lowers, and then opens to dump its load.

The mechanics of the model are fairly complex. For the next series of photos, I have focused on the cab only, and have removed the cab roof and boiler to better illustrate these mechanics. Figure 5 shows the interior of the cab and all of its inner workings (front of cab is at bottom of photo). The drive train assembly consists of:

  1. P58 motor (shaded blue), with attached CJ 24-tooth gear (shaded yellow) (Fig. 6).
  2. A horizontal shaft (P57D 6" axle) positioned near the rear of the cab, just forward of the boiler; a P14 worm gear is mounted near the left end of the shaft, while ladder chain connects the CJ gear on the motor to a P49 12-tooth gear near the right end of the shaft (shaded yellow) (Figs. 7 & 9).
  3. A second horizontal shaft (P57E 8" axle), on the left side of the cab, slightly above the first shaft; it is loosely fixed at the back end, allowing the front end to move up and down about ½". A P14 worm gear is mounted near the front end of the shaft, a P49 12-tooth gear is mounted near the back end, just above the P14 on the lower shaft. An AE spring looped around the shaft and connected to the top of the cab structure holds the front end of the shaft in a raised position (shaded green) (Figs. 9-11).
  4. A third horizontal shaft (P57D 6" axle), positioned at the front of the cab, at just under the height of the rear shaft; the shaft has a P7 small wheel mounted at the right end, a CJ 24-tooth gear near the left end, and a "spool" (a sandwich of 2 Z drumhead wheels and a W stack) near the center (shaded orange) (Fig. 12).


Figure 5. Motor/Drive Train Assemblies


Figure 6.


Figure 7.


Figure 8. Right lever detail


Figure 9.


Figure 10.


Figure 11.


Figure 12.

To operate the model, two J 41-hole strips are used as levers that run along each side of the cab, their ends protruding from the rear. Pushing down on the left-side lever causes the front end of the uppermost shaft (green) to move down, engaging the gears at either end with those on the front (orange) and rear (yellow) shafts. This causes the spool on the front shaft to take up string, which raises the digger scoop.

String also connects the digger scoop itself to the right-side lever and to the P7 wheel on the front shaft (orange). Operating this lever opens the raised digger scoop, emptying its contents. This was the most difficult part of the construction to work out, due to the lack of detail drawings in the instructions. I found a workable solution, but whether it matches the one Gilbert used, I can't say.


Figure 13.


Figure 14.


Figure 15.


Figure 16.


Figure 17.


Figure 18.