Like 90% of other geek offices worldwide we have at work several NERF and similar toy weapons floating about. These toys typically fire safe foam darts and projectiles. Not impressed with the performance of my colleague Lester’s NERF Maverick I decided to see if I could build a better NERF gun.
Click on the pictures to see larger versions.
A film is available on YouTube showing the pistol and how well it compares to a standard Nerf Maverick.
Now, this isn’t new. In fact there are forums for doing just this as well as some very impressive homemade NERF guns around online. The site that inspired me most was www.boltsniper.com where Evan Neblett has documented his very impressive and remarkably sophisticated homemade NERF guns. Even more impressive is these have been made by hand. I have the luxury of having a small lathe!
My effort is not quite so impressive. I just wanted to see if I could make a simple pistol that would fire a NERF dart better than the original toys. This is how I did it. Generally the photographs should explain it so I will try to keep the text to a minimum.
The pistol is made from 32mm ID PVC pipe, some aluminium extrusion and aluminium pipe, wood for the grip and various pieces of metal and plastic. The main spring is one I got from Bunnings warehouse. This gun should be able to take a cut down AR-15 spring as used in the Boltsniper weapons but these aren’t that easy to come by in New Zealand. I believe I am legally allowed to buy one but by the time I found that out I already had the Bunnings spring. I may still get one to play with. The idea of a toy gun using a part from a real one appeals to me for some odd reason…
The spring seems to be this one from Century springs. It is 11/16ths (0.687) OD, 6 inches long and the wire is 0.072 diameter with 29 coils.
I will go through the parts in turn.
Here we see the aluminium trigger guard and the screws used to hold the pistol together. I used stainless steel screws. The two small springs are the trigger return spring and the release catch spring.
Next is a bolt and insert that holds the pistol grip to the trigger housing. The insert is a 16mm diameter piece of steel with a 6mm hole threaded thought it for the bolt. On either side is a 3mm threaded hole. The bolt has a small spacer under the head the purpose of which should be clear later on.
The pistol grip is a piece of wood 18mm thick. A 16mm diameter hole is drilled through the grip to hold the threaded insert. A long hole is drilled vertically though the grip to allow the 6mm bolt to pass through it into the insert. The grip is bulked out with an acrylic plate each side. The plates are filed and sanded to provide a comfortable shape. Each plate is held with a 3mm screw that screws into the metal insert in the handle. Each acrylic plate extends past the top of the wooden grip so that when the grip is attached to the trigger housing with the single screw it won’t rotate.
The barrel is made from 19mm diameter aluminium tube. It is held inside the PVC body by two machined rings made from plastic chopping board. Each ring is held into the body by three screws. Two circlip grooves are machined onto the outside of the barrel and the plastic rings slide up against the circlips to accurately position the barrel which then can’t move either forward nor backward. I used an o-ring under one clip to ensure the barrel was a tight fit and would not rattle or rotate in the housing. A standard NERF dart is 1/2 inch diameter, much smaller than the barrel. I used a piece of black irrigation pipe that is a 1/2 inch internal diameter which the NERF darts are a nice, tight fit into. I machined the outside of the pipe to make it a very tight push fit into the aluminium barrel.
The end cap is also made from machined chopping board. This is at the rear of the pistol and the main spring pushes against this when the pistol is cocked. The hole is to allow the plunger attached to a piston to pass through the rear of the gun. A fender washer is attached to the plastic cap with two screws to provide a flat, hardwearing surface for a music wire catch to slide against. The wire is pivoted through the end cap. A small brass piece was pushed onto the end of the wire to stop it falling out. The inside face of the cap is chamfered so the piston plunger will more easily pass though the hole as the piston and rod are pulled back.
The piston is again plastic chopping board. I machined an o-ring groove into it to provide a good seal inside the pistol body. The main piston rod is made from brass tube. Another o-ring is under the head of the piston rod to seal that against the piston. The plunger is designed to be telescoping. The telescoping section is made from steel and is the most complicated part of the pistol. I used a 1/8 inch steed rod to make the moving section. On the far end of this rod is a metal piece to attach the pull ring to. On the other is a small stop. These ends are silver soldered to the rod. In the middle, but free to slide, is the main catch piece. This is machined so that it is a tight fit into the brass tube of the plunger rod and it is soldered in place. The 1/8 rod can now slide in and out of the brass piston tube but it won’t pull out of it. The catch piece has a chamfer on the end so it can easily pull through the hole in the end cap of the pistol. It also has a groove machined into it. It is this groove that the music wire catch hooks into to hold the piston back in the cocked position. Because the stop on the end of the 1/8 rod that is inside the brass tube is a reasonably good fit I drilled holes in the brass tube to allow air to escape from it as the telescoping section moves inside it. I should have made the internal stop on the end of the 1/8 rod smaller so this wouldn’t have been necessary.
Continue onto part 2 here: http://www.asciimation.co.nz/bb/2011/01/19/building-a-better-nerf-gun-part-2