Tabla de contenidos para No 085 July-August 2019 en The Shed

The Gameco building in Villa Street, Masterton was the venue for a forum of knife makers and knife enthusiasts from all over New Zealand on Easter Saturday. The event, which is intended to be an annual gathering, was held last year in Taupo. Gameco is the largest outlet for specialist tools and materials for knife making and blacksmithing in New Zealand and Australia. Among those presenting and demonstrating their techniques was Brent Sandow, one of New Zealand’s premier knife makers, and Shea Stackhouse, who demonstrated his technique for making Damascus steel. Callum Davidson, a young local blacksmith, demonstrated his craft outside where a small forge and anvil had been set up. Liam Croft, from Tinui, showed examples of his intricate swords, complete with rune-engraved handles and detailed scabbards, and Nick…

The grinding of HSS to make drill bits produces metal swarf, grinding-wheel particles, and heat. The drill blank is flooded with Houghton flute-grinding oil to reduce friction; reduce wear on the grinding wheels; carry away both heat and, suspended in the oil, the metal and alumina particles formed by the grinding process. “You can’t grind without oil,” is one of Rick Smith’s sayings. This means that the Kaiapoi factory is plumbed throughout for oil, just like the circulatory system of some gigantic beast. One set of pipes, like an animal’s arteries, carries cool, filtered oil to the machines. These dangle from the factory’s ceiling like outsized plastic umbilical cords. Another set of pipes, vein like, carries hot, debris-laden oil away to the pumps — the heart of the system. There…

Depending on the coating and the drill bit’s use, coating drill bits can be very beneficial. Coatings can greatly extend the drill’s useful life and be more than a marketing gimmick. Rick Smith started his working life testing the durability of drill bits and found that some coatings extended their life, admittedly under extreme conditions, by 100 times. The very thin (3μm) hard coating reduces both the wear of the underlying metal and corrosion. Forming the coating can be very expensive. Some coating chambers cost NZ$2M. The colour of the coating indicates its composition: The Fe3O4 coating added to some of Sutton Tools’ drill bits increases ‘lubricity’, or slipperiness, and reduces corrosion. When used for drilling in iron and steel, edge retention is increased. Uncoated drill bits are best in…

All the energy we use is solar in origin. Wind and hydro, food, firewood, and fossil fuels (coal being old trees; oil and gas being old oceanic plants and animals) can all be traced back to the sun. One canny commentator coined the phrase “sunlit acreage” and referred to fossil fuels as “down acreage”. The sunlight landing on our own acreages, properly harnessed, can displace the need to buy-in external ‘acreage’. The choices for private capture of solar energy are gardening, passive solar housing, and the two we investigate here: water heating and electricity generation. A doubling is coming Although we all dream of not having a power bill, the practical reality is that most New Zealanders are grid tied and are better staying that way. Our grid is 80…

Greg Holster learnt to weld at the age of 12 with his father teaching him gas and stick welding. From then on he has been hooked on the fire, the arc, and molten metal that comes with this trade. He started in the mining industry in Western Australia as a boilermaker first-class welding apprentice and later gained experience in the oil and gas industry with specialized aluminium and stainless welding thrown in. He has had long experience with welding companies since then, particularly in the area of instructing welding-machine buyers how to get the best out of their equipment. After 40-plus years in the trade, Greg still has a passion for welding and the people who use it. He currently works for Lincoln Electric.…

I asked the creator of T2Laser, Zax, about how the T2Laser Windows application works. Enrico Miglino: One of the problems I always find when using programmes for controlling hardware is how to directly manage the settings. I thought it would be very useful to know when using more than one tool how to save a series of presets to work with several tools. Zax: The profiles can be updated, if you left-click to load the values, then change whatever parameters you want (say increase from two to three passes) and then right-click to save. You can change the name if you wish and it will override the new parameters. Alternatively you can edit the T2LaserProfiles.txt file directly. It is in the T2Laser install folder. You can find this in the…

When my wife and I were in Japan in 2006 we visited a traditional Japanese knife maker on the island of Kyushu. He is one of a handful of traditional knife makers left in Japan, with the family business stretching back for 250 years. The interesting thing was that he heated his forge using used engine oil. The burner was a very simple oil-atomizing arrangement using compressed air blown over a nozzle. The oil was directed into a brick furnace in which he heated his knife blanks. You can see a video of his furnace on The Shed website. The furnace ran with no apparent smoke or smell and achieved temperatures in excess of 1100°C. It inspired me to try to make my own. There is always something fascinating about…

Southmach, a two-day technology trade show, was this year held on 22–23 May at Christchurch’s Horncastle Arena. Large manufacturing companies are the logical customers, but a lot of the gear and services would be suitable for the home workshop. Tiny, efficient stick welders for around $1K were on a couple of stands, and bottled-gas suppliers were prominent. It was interesting to discover how things are changing (and improving) in these two areas. A number of exhibitors displayed stuff made by 3D printers. It is possible to produce extremely complex items in small numbers by 3D printing. Plastic, titanium, and silver items were shown and it is obvious that the price of these processes is becoming much more affordable. What this means for traditional manufacturing is anybody’s guess, but printed items…

At Sutton Tools’ Kaiapoi twist-drill factory, three lots of industrial robots are used. Most of the operations carried out in the factory are too variable to be easily automated, but the laser etching and packaging of drills is undertaken by two pairs of robot arms. These dull and repetitive tasks are exactly the sort of jobs that are worthwhile to leave to machines. Most robots in New Zealand are used to ‘pack and stack’, especially when the items being moved are heavy. Sutton Tools’ robots were provided by Christchurch robotics company Design Energy. Managing director Mike Shatford says that as the cost of robots has reduced so dramatically over the past decade and their capabilities have increased, they have become much more attractive to small-and medium-sized businesses. This is highly…

If you are going to weld something, and especially if you want repeatability, you owe it to yourself to get a Rhino Cart TDQ612075-K1 modular fixturing station. This US-made welding table is special because of its system of stops, locks, chocks, and clamps that make it easy to fix and hold workpieces while you weld. The 16mm thick, spatter-resistant reversible tabletop measures 1200x750mm and sits on a rolling chassis equipped with locking castors, which has room for your welder as well as the rack of attachments. The tabletop is drilled with 16mm holes at 50mm spacing into which you drop smooth-sided locating pins that are locked in place with a twist-top that pushes out locking steel balls under the table. They are secured with a hex key. Clamps and wedges…

A cycloid geometrical movement has a number of applications in the study of equations, as well as in mechanics, science, and other fields. ‘Cycloids’ — curves traced from a point on a circle rotating along a linear path — are involved in a number of equations in trigonometry and geometry. For example, cycloids are used in mechanics to calculate the movement and size of the gears to design gearboxes for speed reduction. As shown in the cycloid scheme (page 73), if we ideally put a pen where the rotating point lays, it draws a series of chained arcs. Things become more interesting if we apply some constraints to the circle with the drawing point. Suppose, for example, you add support to the rotating circle by placing the point external to…

I grew up a petrolhead, in a petrolheaded world. As a teenager, I could discuss Nuvolari’s 1935 German Grand Prix win, Jim Clark’s jaw-dropping arrival at the Brickyard, Henry’s iconic 1912 twin-cam Peugeot, Ettore Bugatti, George Eyston, two-stage superchargers on the Merlin … Then I read the 1976 McGraw-Hill Encyclopedia of Energy, which still graces my bookshelf. And came across the writings of M King Hubbert, sometime petroleum geologist, sometime professor. And realized that not only do we use fossil fuels incredibly wastefully but that — very soon in human history terms — they would be moving away from us. “It’s called ‘thermosyphoning’, and we figured that if we applied it to the air in the house we’d be tapping into free circulation” The chase begins That spurred a lifetime…

A nicely made chest can be a handsome addition to the furniture of any home and it is the sort of project that most sheddies will tackle sooner or later. A well-made and evocative chest can easily become an heirloom passed down from one generation to the next while quietly and unobtrusively fulfilling its primary function of being a storage receptacle. I can still recall in detail the chests and trunks that my parents had of which my siblings are now the custodians. A job worth doing well When you embark on your own journey to make one, remind yourself that you are laying down memories for your children and descendants yet unborn. Chests have a myriad of uses around the home, housing blankets, clothes, camping gear, toys, shoes, socks,…

After seeing the Japanese forge running on used engine oil I was very keen to try my version of it on this little forge. The principle was very simple. If you spray oil into a hot forge it will burn very well without any smoke or smell. I found that a litre of diesel in four litres of used engine oil made it run much better than just straight engine oil (Image A). The oil spray is made using two 0.9 mm MIG-welding tips (B). The fixed bottom one is the oil supply, which goes into a four-litre container of used engine oil. The top tip blows compressed air across the oil tip creating a vacuum that sucks the oil up from the container. It is adjusted by the screw…

What sort of people go to the trouble of building complex and dangerous robots and then smash them to pieces? The crazy builders from Combat Robotics NZ, that’s who. Combat Robotics organizes events where small but destructive robots fight to the death in arenas clad with enough polycarbonate and steel to actually be bulletproof. These robots are often 3D printed and use motors and electronics adapted from the multicopter and radio-controlled (RC) community. People of all ages and abilities produce different types of machines — some simple wedges that get under another bot and force it into the pits, others with nasty spinning blades or flipper arms intended to control the opponent or, preferably, destroy it. At their nationals in Auckland on 25 May, more than 30 competitors fought in…

Most shed-based activities — metalwork, woodwork, rebuilding old tractors, even jewellery making — require the drilling of holes. The first power tool most sheddies buy is a battery-operated electric drill. The twist drills that are used to do the actual drilling last much longer today than they did in the days of musclepowered egg-beater drills, but they do wear out or break eventually. They can be resharpened but generally not to the same accuracy as a new drill, so there is a continual demand for twist drills. Our local drill maker Before New Zealand adopted a more open economy, local manufacturers were protected by steep tariff barriers, so it made sense for overseas businesses to set up local manufacturing operations. One company that did this was Australian-based Patience and Nicholson…

The Kaiapoi factory makes 280 types of drill. They differ in their diameter, length, shank type, coating, and tip. The shank can be straight, reduced, or tapered. There are three series of diameter: metric, imperial, and ‘number’. The metric diameters increase from 1mm to 3.5mm in 0.05mm increments, and from 4mm to 13mm in 0.5mm increments. Imperial drill bits increase in size by 1?64 inch. Number drills have diameters from 68 (1.25mm) to 1 (5.76mm). The tip can have different angles and be chisel point or split point. Split-point drills are more expensive because they require an additional grinding operation to add another facet to the tip, reducing the size of the chisel point. They aren’t as durable in more stable drilling environments such as drill presses, but they can…

More electrical equipment is coming out with safety or hazard-reducing components and welding equipment is no exception. Most welders have had a shock and laughed about it, but it can be serious. The voltage reduction device (VRD) is to welding machines as the safety airbag is to cars. VRDs reduce the hazard of electric shock by automatically reducing the open circuit voltage (OCV) between the welding output terminals when you are not welding. Welding machines for MMAW and similar CC processes, supply a higher OCV between the electrode and the work when the welding machine is switched on and ready to commence welding. The OCV is often higher (60–100V) than when the arc is established and welding current is drawn (15–35V). Consequently, the greatest danger occurs when handling the electrodes…

As winter approaches and power outages become more likely, we thought it might be useful to identify what you need to know about generators, safety, their uses, and how to connect them to your home. A ‘generator’ is a motor driving an alternator to produce power, and with the advent of inverter generators (see my review of Honda inverter generators on pages 82 and 83) the basics haven’t changed, but how they operate has. Safety Like all motors burning fuel, generators give off carbon monoxide. This is a colourless, odourless killer that makes you fall asleep and doesn’t trigger any safety reflexes in the brain, so it will kill you. While the fumes are deadly, the heat from the exhaust outlet can also burn anything combustible if it’s too close.…

In the previous articles of this introduction to laser cutting and engraving with domestic and DIY devices, we have explored the key aspects of the tool: laser power, materials, cutting thickness, and use of the Z-axis. The use of the laser machine is fast growing as a good and cheap alternative to 3D printing technology for some types of tasks. The mechanics and electronics of domestic laser tools are relatively easy to manage and maintain, with fewer issues than 3D printers, but the most painful issue is the software. I started writing on laser technology more than six months ago and the software options currently available today are almost the same. Finding the right software is a key factor to achieving good results. Lack of choice Chinese producers do not…

As people live longer and more baby boomers hit retirement age, the number of people choosing to live in retirement or rest homes and take it easy is also rising. This older generation has a massive collection of diverse skills, acquired from the days when people fixed things themselves, when men got together to build a house, add a room, make hay on farms, or lay a concrete pad or driveway. A time when do-it-yourself dated back to pioneering days and many people acquired and passed down skills through the generations. If you didn’t have the skills, then someone you knew could plaster up your Gib board, rewire your car, change a head gasket, or had a concrete mixer in their shed — maybe one turned by hand, but it…