Win this builder’s tool belt complete with tools

Build your own deck

Build your own deck

Building a great deck for typical Kiwi indoor-outdoor living is on every home-owner's list at some point. The deck we are building here is a fairly normal slatted timber deck less than one metre high. This article is an overview of general steps in building a deck and is intended as a broad illust...

Arduino, PICAXE microprocessors compared

Arduino, PICAXE microprocessors compared

In creating a fully automated target, with spring-back target buttons controlled by microprocessors, I was able to compare the workings of Arduino and PICAXE. Arduino and PICAXE  are two very different devices—like comparing a revolver and a shotgun. There are smaller Arduinos and bigger PICAXE...

My shed the barn

My shed the barn

When designing a house, first build your giant shed where you can make joinery for the house-to-be. That was the thought of Julian Pirie. But he was to take a special route—he decided to model his barn-like “shed” on old-style English oak barns, typically housing Aston Martins in magazines p...

Make a handy, small robot

Make a handy, small robot

Without knowing electronics, it’s easy to tackle this small robot which demonstrates how a machine can be programmed to back off obstacles it hits. Mark Beckett helped to construct his daughter Hayley’s easy-to-make “HaloBOT” which is controlled by PICAXE. You can follow the building proce...

My Dad’s man-cave

My Dad’s man-cave

Restoring old motorbikes and cars is Dad’s passion. The garage is home to four of Dad’s prize beauties all lovingly semi-restored in various stages of TTI (Time Till Ignition). The projects in question are two cars: 1956 Wolseley 6/90 Series 1 and 1935 Hudson de Lux 8 (side-valve, straight-eig...

Steam-bending

Steam-bending

This project to make a stool was developed as a way of introducing students to a number of basic wood-bending and shaping techniques, whilst also giving experience in several useful applications of the router. The stool consists of two legs in the form of continuous steam-bent hoops or arches, whi...

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Create a golf ball cannon PDF Print E-mail
Written by RICHARD FELTHAM   

Create a golf ball cannonThe principle of the golf ball cannon is simple. I used a  standard electric air compressor to pressurise an airtight reservoir to around 100 psi (700 kPa or 7 bar equivalent). This high pressure holds a freely moveable piston against the breech which effectively seals the reservoir exit.
The area on the front of the piston that is exposed is reduced because the front is up against the breech. Thus, the total pressure on the piston here is relatively less than the air pressure which pushes on the rear and holds the piston firmly against the breech, preventing the air from escaping. The rear of the piston is open to the atmosphere via a quick-acting valve.
Opening this second valve precipitously reduces the pressure behind the piston suddenly and it recoils, immediately allowing the pressurised contents of the airtight reservoir to escape along the barrel, accelerating the golf ball.
For obvious safety reasons it is important to use high-pressure PVC components, obtainable at any plumbing supply outlet. Rated to in excess of 800 psi, these will give you a reasonable safety margin. Guttering downspouts and the like are not suitable. There are no particular tricks to making the body of the cannon, but do allow at least 24 hours for the PVC adhesive to dry before you test it with pressure.

Read more in the April/May 2010 issue of The Shed

 

 
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