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#1
21-09-18, 18:50
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Quote:
In the scan of the Finnish manual that has exploded diagrams of the corrector and sights on pages numbered 34 and 35, there are lines leading to a set of 'U' numbers... ie U1 to about U48. Is there a key where these 'U' numbers (presumably part or component numbers) are listed and described; if so, would it be possible to get a scan of that please ? Thanks in anticipation Richard 
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#2
17-10-18, 16:10
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On another tack.... we've been looking at the electrical wiring that is on our Bofors. A lot of it is for lighting; this is run off a 6v battery and the wiring and connectors are all (naturally) low current. We can trace the wiring runs pretty well.
However..... there are some items we are not sure about. There are a couple of heavy-duty pin sockets just to the left of the ejection chute; one has a lead that goes into the centre of the revolve drum, and another lead that goes to a pretty chunky brass brass socket that is positioned just left of the ejection chute. All this is totally separate from the lighting wiring, and we have no idea what it is all for. It looks like you would plug a power supply into one part of this, and some device that needs power into the other; we have no idea why one lead goes into the revolve drum, as it is inacessible and has not electrical brushes on it. The gun is all manual.... no electric motors anywhere. I'll post some photos below. Any ideas anyone.... ? Incidentally, from info in the Terry Gander book we now believe that 'our' gun was made in Poland in about 1942 (but to the 1938 design) and was shipped to Portugal.
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#3
11-12-18, 18:21
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On another tack.... someone mentioned that the Corrector had a habit of turning as the gun traverses. Ours does the same.... we are now pretty sure we know why this happens, and that it is deliberate. If anyone is interested let me know, I'm happy to explain.
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#4
20-12-18, 15:09
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Another new question... we have to replace or retemper the set of balance springs that support the weight of the barrel when it is elevated. [They are housed in the two cylinders that sit below the barrel]. Unfortunately, we dont know how 'springy' the springs should be. I gather this is expressed in engineering terms as the 'spring rate' and is the weight required to compress the springs by one inch.
Does anyone have any technical info about the characteristics of these springs, especially the spring rate value ?
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#5
20-12-18, 17:14
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I can't say for sure in British gun terminology, but in North American terminology they are equilibrator springs. Basically you tension them until you have easy, almost balanced, elevation from level. Since there are two in this case, you will balance them left to right.
I was just involved in doing this with a M109 the other day, although they are equilibrated by hydraulic/nitrogen pressure. If you need to know the length of new springs, I believe I have some at home, and there may even be one or two kicking around this museum.
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#6
21-12-18, 14:40
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Hi Rob, many thanks for your reply.
Unfortunately... the springs in our equilibriator are already adjusted to the maximum possible, and still dont balance the weight of the barrel. Hence they need to be retempered or remade... but we of course need to know the spring rate to temper or construct them to. Any chance you could place a known weight onto a spring (held vertically) and measure the displacement ? We could work out the rate from that. As is the way of things I cant offer much by way of returning the favour.... though if your gun has the Bofors Speed and Course Sight fitted (as does ours) then I can share with you our discoveries about how it is used... Thanks and best regards Richard
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#7
16-03-19, 12:24
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General update about the Bofors at The Shuttleworth Collection in the UK. ....
.... after much huffing and puffing we successfully removed the six balance springs from the gun, discovering along the way that one was broken. Our friendly spring factory says that they cannot be retempered (as they cant tell what material they were made from or how they were made in the first place), and also says that they cant make new ones using rectangular-section strip. So... does anyone know of a source of unused balance springs, or has anyone successfully made replacement springs from round section strip ?
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