Twist drills
A NEW ZEALAND-BASED COMPANY HARNESSES YEARS OF EXPERTISE TO MANUFACTURE TWIST DRILLS
Profiling the New Zealand–based company Patience and Nicholson, which harnesses years of expertise to manufacture twist drills in Kaiapoi
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 (P&N), which made metalworking taps, dies, and drills, among other things. In 1962, with a New Zealand partner, P&N set up a drill and hacksaw-blade plant in the Canterbury town of Kaiapoi.
The years since have not been kind to New Zealand manufacturers. The protected market was thrown open to international competition, including from very low wage economies, and profit margins were savaged. By the 1990s P&N was struggling, new equipment was financially impossible, and the factory plant was kept going with Kiwi ingenuity rather than money. P&N could have gone into oblivion in the same way that many venerable New Zealand companies with no competitive advantage in the new global economy did.
The factory plant was kept going with Kiwi ingenuity rather than money
Upgrading machinery
Sutton Tools was established in Melbourne in 1917 as a one-man toolmaking shop. It grew into a considerable business, which is still owned by the Sutton family. It would be an unusual shed that didn’t have some Sutton Tools’ taps and dies in it. In 1994 Sutton bravely bought P&N and invested heavily in upgrading the Kaiapoi factory’s machinery. In 1995 Sutton brought in Rick Smith from its Melbourne operation as factory manager. Sutton Tools’ Auckland-based New Zealand manager, Kevin Donovan, says that “Suttons saved us”. Today
the Kaiapoi plant makes two products only: twist drills and machinery to make twist drills.
The Kaiapoi factory’s manager, Rick Smith, has an encyclopaedic knowledge of drill making. He graduated in manufacturing engineering from Melbourne’s Swinburne University in 1980 and started work in Sutton Tools’ Melbourne headquarters testing drill bits in 1984. Leadership is Rick’s thing. He is the immediate past president of The Manufacturers’ Network in New Zealand.
Electronically controlled machines
The factory buildings in Kaiapoi are largely unchanged since 1962, but the technology involved in making drill bits is radically different.
Drill-bit grinding machines used to be controlled by very complicated cams and gears that had to be manually readjusted for every different drill size, inevitably leading to variations in the sizing and finish of the bits. Today all the machines are electronically controlled, with a staff member responsible for three machines. The worker will load the hoppers in the grinding machines with drill blanks and monitor the machines’ operation. The drill production takes place inside closed cabinets in a spray of expensive Houghton flute-grinding oil, so it is very hard to see what is going on.
An advanced machine will operate
on eight axes and have three spindles to hold grinding wheels. The process to make the drill bits varies slightly depending on their size. For sizes smaller than about 4mm, it all happens inside one machine. With the carefully ground and heat-treated high-speed-steel (HSS) blank held in a collet, an aluminium oxide (alumina) wheel grinds a spiral groove, or ‘flute’, into it.
Another wheel then grinds a relief next to the flute to form a cutting surface on its edge. These actions are repeated on the opposite side, leaving two flutes winding around the blank. Another grinding wheel then forms the cutting edges at the tip of the drill — all in a few seconds. Larger drills have the tips finished in a separate process in a separate machine.
Quality control
Sample drill bits are regularly checked with specialized equipment to ensure that they are within specifications for diameter and cutting angles. The grinding wheels are automatically dressed at intervals inside the machine, which then compensates for the reduction in the wheels’ diameter. The ground bits are heat-treated in red-hot molten
It would be an unusual shed which didn’t have some Sutton Tools’ taps and dies
salts, may be thinly coated with black magnetite in a furnace, are laser etched with brand and dimension, and are packed in various styles of packaging ready for shipping. Rick Smith says of drill-bit manufacturing: “Costs are high and margins are low.”
The blanks are made in Sutton’s Melbourne factory from HSS, which is mainly imported from France (Erasteel) or Germany (Böhler) and shipped to Kaiapoi by the container load. In Australia, HSS wire or rod is straightened, cut, ground to size, perhaps has the shank reduced, has a point machined on one end and is heat treated. The integration with Australia is completed with most of the finished drill bits being exported to the Australian market in the same containers. They are sold under the Sutton brand in Australia and the Evacut brand in New Zealand. Most local industrial-supply, fastening, and hardware/DIY retailers are very supportive of the locally made products.
Continual factory upgrading
The Kaiapoi factory’s 102 staff runs three shifts each day, with an annual production of more than 12 million bits. A container load of product leaves for Australia every two weeks.
Sutton Tools is unusual in that a very large proportion of its profits is reinvested in the business by its owners. This allows for the continual upgrading of the Kaiapoi factory’s plant. During the hard times, before Sutton took over, considerable skill in equipment maintenance and modification was developed and this has led to ‘cuttingedge’ drill-making machinery being designed and made on the Kaiapoi site. About 10 of the staff, including two apprentices, work on the design and fabrication of the machines
A container load of product leaves for Australia every two weeks
under the direction of engineering manager Glenn Morgan. Richard Frew is chief designer. The engineers use Alibre 3D solid-modelling software, which is highly regarded, despite it being reasonably inexpensive. The machines’ components are produced by Christchurch engineering companies such as Tatom Engineering.
The electronic control systems are the work of Anca Motion, a division of Anca, a large Australian manufacturer of CNC tool and cutter grinders. The chassis of the machines are assembled with a polymer concrete and steel base. It has been found that hand scraping is needed to get a base that is sufficiently flat to make a machine which can produce drill bits with an accuracy of plus or minus ∕100 of a millimetre.
1 Milling machines flatten the steel base as far as possible and then an engineer spends three days of very hard work with a granite surface plate, engineer’s blue, and a scraper to make it completely flat. The large and complex machined components are assembled on the base, the sheet-metal case supplied by Jericho Walker Sheetmetal Engineering is fitted, and the electronic control system installed. The engineers have made 30 of these machines; the ones that they are currently working on are the third generation of the evolving design. The drill-making machines are made not only for the Sutton Tools factories, but also for outside customers, with one set to be exhibited at a trade fair in China in the near future.