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Merkur Industrial Machine Tool Series: Model No. 302 - Upright Iron Planer

Hi folks, Doc here, with a new model from the Nejstarsi ("oldest") Merkur manual (you can download a copy of the manual from my 1920's Windmill pictorial here in the Model Gallery, or from the G-Files page). This model represents the first in a new series of pictorials that I call the Industrial Machine Tool Series. The Nejstarsi manual features a number of designs modelled after machine tools of that period (1920-1938). I'll present six of them in the series, beginning with this one: an upright (vertical) iron planer.

The various machine tools in the Nejstarsi manual are apparently modelled after real tools of the period, including one called the Buchar "Ajax" (Ajax Power Hammer). The real versions of these tools may in fact have been Merkur's own, as their parent company Cross still produces real industrial machine tools to this day. Most of the models feature elegant styling with an Art Deco influence. One of the most interesting of these is the subject of this pictorial, shown at left (from the illustration in the manual).

Although Merkur parts have remained almost unchanged over time, the contents of the various sets have apparently undergone some changes. According to the manual, this model could be built with the No. 7 Set (of the time). I built the model with a modern No. 8 Set, and I still needed a few extra parts to complete it. My version is an almost identical replica of the model shown in the manual, Model No. 302. The only modifications I made were to the external driveshaft mounts, and to the attachment points of some of the strips that form the housing. I also had to guess as to the exact construction of the "business end" of the machine: it was clear that the tool assembly located there moved up and down, but I couldn't see how it was actually attached to the body of the machine so that it could move without flopping around. A pair of vertical rails, or tracks, mounted along the front edges of the housing would allow the tool assembly to move properly, but no such features are apparent on the design. So, I added two pair of No. 1102 T-brackets to act as guides for the tool assembly as it moves, which did the job. Finally, I added a few enhancements not included on the original version: I motorized the model, and added lights over the work platform. I will describe the details of these features later in this pictorial. My final result is shown in the photos below.

As the images on this page show, the machine consists of a tall, narrow body with the aforementioned tool assembly mounted vertically on the "front" end above a work platform made of two horizontally opposed rectangular surfaces. A centrally located horizontal driveshaft sits high up inside the body of the machine.

A No. 2047 119-tooth 81mm gear on the rear end of this shaft meshes with a No. 1046 17-tooth 11mm gear on the front end of a second driveshaft mounted parallel to and outboard of the first shaft (shown above). An 85mm drive pulley is mounted on the rear end of the outboard shaft; between the gear and the pulley are a series of three smaller pulleys that function as flywheels, and can also be used to drive other machines.

A No. 1042 42mm pulley is mounted on the front end of the central driveshaft. A short axle and coupling are connected to one of the holes around the edge of the pulley (shown above). A second coupling and short axle are attached to the top of the first axle to form a 90º angle. The other end of the second (horizontal) short axle is attached to the top of the tool assembly described earlier. Rotation of the central driveshaft and pulley causes the vertical axle to move up and down, thereby moving the tool assembly up and down - click the video link above to see how it works.

Although the original design did not incorporate a motor, the model is a perfect candidate for automation. So, I bolted another No. 1036 flanged plate to the rear of the model base, and mounted the motor to it using a pair of motor brackets. With the motor shaft pushed forward to engage the low gearing and a No. 1040 small pulley mounted on the end of the shaft, I connected the motor pulley to the large drive pulley above it using a rubber o-ring (shown above - thanks, Larry).

As I describe elsewhere on this site, the Merkur motor is battery powered, and will run on 4.5 or 6 volts; the included battery case holds 3 "C" size dry cells. I powered it this way first, and it worked fine. However, I also decided to use the Merkur lighting parts to add another dimension to the model, and the included bulbs are 6 volt. So, to simplify things I decided to power both the motor and the lights using my switchable low-voltage power supply. This handy device transforms standard AC house current into 3, 4.5, 6, or 12 volts DC with the flip of a switch. I use it most often to power 3 volt LEDs, such as those I used on my Rocket Jets ride that you can see here in the Model Gallery. I mounted the lights together inside the front of the housing just behind the tool assembly and above the work platform; see the photo below. The final model is a terrific display piece that runs smoothly and looks great.