Oil Pump Jack
08/20/2006
This page describes a little bit about the Walthers Cornerstone kit #933-3248. This is an N-scale oil pump jack, which has an optional motorization kit that can be installed to make the unit animated. The motorization kit number is 933-1050. I bought both of these when they came out in 2001.
Oil Pump Jack
I don't have any assembly photos, because that was before I started actively documenting my various projects. I remember that the instructions were good. This kit was very popular, and you can see them on various N-Trak modules everywhere. However, I noticed that a lot of people had problems getting them to animate properly. First, you have to be very careful when assembling them, so as to not get any glue on joints that are supposed be movable. Secondly, the motor kit has to be assembled correctly and carefully to get smooth movement from the gear reduction box. After a while mine started working better.
Oil Pump Jack
I built the model and installed the motor, but I never placed it on a layout. Following the instructions that came with the kit produced a horrible-looking solution for the up and down movement of the jack's "wire", as seen below.
Oil Pump Jack
I finally decided to use it on my (what turned out to be my last N-scale) layout. I wanted to build a diorama so that I could work on the model offline, so to say. A simple piece of left-over Masonite hardboard serves as the base for the diorama. I marked off where the unit will sit on the base, and drilled four small holes to prepare cutting a rectangular hole. Then I used a jeweler's saw to cut out the hole. Next, I lined up where the wellhead hole is to be, and drilled a larger hole in the Masonite board. This is where the metal rod goes "under ground". I used 5-minute epoxy to glue the model to the diorama base.
Oil Pump Jack
On the under side of the masonite board I installed a barrier strip and routed the motor's wires to it. One wire had four 100-ohm resistors in series to reduce the speed of the motor when powered by a 12-volt power supply. The motor's gear box can be quite noisy. Slowing it down helps reduce that noise a good bit.
Oil Pump Jack
I found that the motor runs fine on the lower voltage, however, sometimes when I turn the system on, it won't start. The motor really needs a higher start-up voltage. I installed a pushbutton switch that temporarily by-passes three of the four 100-ohm resistors. This gets the motor started. Once started, it will keep going, and I can let go of the button.
Oil Pump Jack
I covered the holes in the base of the model and the transition from the Masonite board to the base of the model with some premixed grout. That stuff works great as a filler, hardens in minutes, and can be sanded and painted. I purposely left it a bit rough because my model is supposed to sit on a concrete base, but it has been overgrown with sand, weeds, and bushes. I painted the whole base with Poly Scale's "Dirt", which is a dark brown.
Oil Pump Jack
I removed the thread idea that the kit's instructions suggested. It tried a few experiments, but this last one is the one that I am the happiest with. I installed a 0.012" brass wire through the hole. Many years ago I bought "HO-scale" chain link from Clover House. The smallest they offer is usable in N-scale. I glued a small piece of this chain to the top of the jack and to the brass wire. I used superglue. The kit's instructions say to hang some weights off of the brass wire, but I found that the gearbox caused the jack head to jerk a lot. I left off all the weights and the unit worked smoothly.
Oil Pump Jack