First, we need a stock image.

Once you've obtained an image of your weapon in question, preferably a side view, you now need to formulate a plan.

- The grip/receiver assembly : This is largely an extruded object: the part we need to make looks exactly like this from the side view, but pulled out so it's thicker. Think of what a cube is compared to a square. You'll be making it like a block shaped like this section.
- The Barrel: This is going to be one of the easiest, yet annoying parts to make. It's just a hollow tube, followed by a shorter, hollow tube, connected with some small rectangular spacers. Not to mention, some bracket thing on the front.
- The Pump: You're going to hate this part with a passion. Especially if you have the tooling capability of an Amish man with a metal allergy. Look no farther, ye of little machinery.

For part 1: the grip/receiver, you simply need to trace that section onto paper, cut that out, then trace it onto some 4-card stacks until you have 4 parts. This will be approximately 5mm wide, which is the width of our shotgun.
You can simply glue these four pieces together now and sand down the edges flush. Advanced methods involve notching two 5mmx3.175 notches to receive a 3.175mm diameter bamboo stick, as indicated in the lower image:

For the barrel tubes, you'll need to use this reference on making tubes, or this Excel file for making tubes and cones out of paper. That is, if you want to precisely make 4.5mm outer diameter/3.175mm inner diameter tubes. I like my tubes to be as close as possible to the desired dimensions. Cut them to length, and make some 1mm spacer blocks to hold the two tubes together.
Now for the hard part: the pump. This part involves the lower half of the schematic. The lower left covers the dimensions in third angle projection. The lower right covers the concept and upper assembly to hold the pump in place.

If you draw the leftmost figure in the above image to the specified dimensions in 110lb cardstock,then roll around a 5mm diameter rod, you'll get the shape of the shotgun pump. the dimensions were calculated using my cone frustum calculator. It uses the same principles listed in the tube making reference, but with some fun tricks. If you roll up a triangular sheet, you'll form a cone. If you roll up a sheet that has a lot of triangular sections like the one I drew up, you'll form a shape that looks like the shotgun pump, if revolved around the magazine tube axis.
After you've made this solid, you'll need to use your cutting tool of choice to cut out a V shaped notch on one side of the pump. This is shown in the bottom right of the schematic. I'd suggest cutting 2mm wide and flaring out to 5mm. Next, you'll need to cut out that U shaped rectangular piece shown below and fold it to form a U shaped trough.
For the barrel tubes, you'll need to use this reference on making tubes, or this Excel file for making tubes and cones out of paper. That is, if you want to precisely make 4.5mm outer diameter/3.175mm inner diameter tubes. I like my tubes to be as close as possible to the desired dimensions. Cut them to length, and make some 1mm spacer blocks to hold the two tubes together.
Now for the hard part: the pump. This part involves the lower half of the schematic. The lower left covers the dimensions in third angle projection. The lower right covers the concept and upper assembly to hold the pump in place.
If you draw the leftmost figure in the above image to the specified dimensions in 110lb cardstock,then roll around a 5mm diameter rod, you'll get the shape of the shotgun pump. the dimensions were calculated using my cone frustum calculator. It uses the same principles listed in the tube making reference, but with some fun tricks. If you roll up a triangular sheet, you'll form a cone. If you roll up a sheet that has a lot of triangular sections like the one I drew up, you'll form a shape that looks like the shotgun pump, if revolved around the magazine tube axis.
After you've made this solid, you'll need to use your cutting tool of choice to cut out a V shaped notch on one side of the pump. This is shown in the bottom right of the schematic. I'd suggest cutting 2mm wide and flaring out to 5mm. Next, you'll need to cut out that U shaped rectangular piece shown below and fold it to form a U shaped trough.
Now all you need to do is add details. The trigger is made from a 3mm wide strip of Magic card, three layers thick. I simply curved the part to fit the drawing and glued it in place with some Loc-tite for extra quick adhesion. To smooth out the pump, I sanded mine down until it was relatively flush. I then used the cone maker formulas to create some cover parts to wrap around the pump sections. This took care of the major surface irregularities.
All you need to do now is add the little details, which should be easy compared to the pump. For the side ejector port on the left, simply cut out a 12mm x 3mm rectangle on the side as depicted on this screenshot:

No comments:
Post a Comment