COMPASSES
Compasses – products made with precision and feeling Olle Bergman COMPASSES, COMPASSES, COMPASSES – small, large, antique, modern. I thought I knew everything there is to know about compasses. Standing in front of a display case in the Silva premises in Sollentuna I start to feel nostalgic thinking of my first compass, purchased from my club in 1976: an angular base plate compass with aluminium housing and a reliable magnifying glass. I never treated myself to a step counter.….. Wide assortment My energetic host, Christer Svensson, takes me back to reality. He’s eager to show me the assortment of today, which includes everything from marine instruments and GPS equipment to compasses with built in whistles and can openers. Our attention quickly focuses on the products that were there when it all started for Silva in the late 1920’s – orienteering compasses. Christer starts to describe the production, and it hits me how little I actually know about the instrument which has been my guide in darkness and in marshes. To produce a standard compass is certainly not simply putting a magnetic needle in a plastic can and filling it up with paraffin oil! No, it’s a production that requires precision and knowledge of the materials.
automated. Every single compass is balanced and glued by hand.” The main difference is that the Jet compass does not have the traditional compass needle. Instead it is structured on a small square magnet on to which a plastic needle has been attached. The compass needle requires manual balancing (see picture), unlike the metal needles which are punched out of a set form.
Electronics in the future More and more of the Silva products will be electronic, but to make a simple electronic compass suitable for orienteering at a reasonable price is not so easy. The problem lies in the vertical factor of the earth’s magnetic field. Cheap electronic compasses are extremely sensitive to tilting – to the extent where they are useless to orienteering. Another problem is the practical use of an electronic compass. How do you set a compass course when you can’t see the map and the north lines or turn the compass housing. However Silva is preparing for an electronic future for the sport. “We think – and hope – that GPS will not be allowed in orienteering, but we think that the electronic compasses will be allowed. Speaking for myself I would like to see more interesting supplementary sports to get more people interested in orienteering, e.g. GPS orienteering”, says Christer Svensson, who himself has tried geocaching with great pleasure. What kind of gadgets our kids will take with them out in the forest is hard to tell, but it’s very likely that some of the gadgets will be branded Silva. Olle Bergman is a Swedish freelance writer. First published in Skogssport 2/2006.
A lot to take into consideration Christer shows me the frictionless suspension, where the sapphire stone hub rotates on the pin in the housing. He tells me about the liquid, ‘a petroleum product that resembles paraffin oil’. The liquid has to remain clear and uncoloured. He explains how important it is that the plastic wall of the housing has the exact amount of flexibility to allow for the volume changes of the liquid – no cracks caused by summer heat, no bubbles caused by cold weather in the winter. When Christer talks about balancing the compass needles, because of the vertical direction of the earth’s magnetic field, we reach the hard hitting question: why are the speedy orange needles of the Jet compasses so much more expensive than the classical red needles? Do they really differ all that much? I’ve been asked the same question so many times: why does a compass cost around $140? The answer is - it’s made by hand!
Different manufacturing Conventional compasses, with a needle punched out of steel plate, are rather simple to mass-produce, whereas the more modern orienteering compasses require a more complicated process. “This production must be made by hand”, Christer Svensson explains. “It cannot – with reasonable investment costs – be 30 THE AUSTRALIAN ORIENTEER JUNE 2006
’Standard’ compass needles punched out of steel plate. The needle is magnetised by a strong magnetic field as the compass is being put together. If the compass is to be used at Scandinavian latitudes, it will be slightly heavy at the back. This is to stop the Earth’s magnetic field to tip it forwards/ downwards. The Jet compass is more complicated than you may think. If you look very carefully you can see the transparent dampening disc that settles on the needle a second or so after it is aligned to north.
