Chris M Posted July 3 Share Posted July 3 17 hours ago, Deeps said: I well remember when the RN Submarine Service went metric, with the introduction of the Trafalgar Class. When your brain is full of details for significant pressures, dimensions & levels etc. it takes a while to wipe them from your memory bank and replace them with the metric equivalent, often direct conversions which seemed irrational. Interestingly on the Trident boats, which are nominally metric, the American bits (missile systems) are imperial! Which reminds me of an occasion during my days as a design engineer in the dockyard. One of our team had been doing some survey work on a submarine and when his measurements were examined one of them was for 2 metres 5 inches. I see nothing wrong with that measurement. I once had a layout where the boards were 1 metre 1 inch long. I designed, made and measured them myself and it was how they were meant to be. These boards consisted of 1 metre long side timbers with half inch ply on each end. I must admit to getting funny looks when I was asked about the size of the boards. I couldn't do the same today of course because you just can't get half inch ply. I use 9mm ply instead these days. 1 1 3 1 Link to post Share on other sites More sharing options...
Deeps Posted July 3 Share Posted July 3 7 hours ago, Michael Hodgson said: The top speed of a sub isn't going to change even if you express it in furlongs per fortnight. Surely it doesn't matter what units it's calibrated in, as long as you know where the needles on the pressure gauges should be pointing? Generally speaking this is correct; all that is required for safe watch keeping is a quick glance at a meter to reassure you that all was well. However, submarines are fairly dynamic vessels with hundreds of parameters to be monitored, often with a range of acceptable readings dependent on the situation at that time. As a qualified submariner you need to know all of this without reference to documentation or where the needle should be pointing. If I was being examined to prove I was competent to operate a nuclear reactor it wouldn’t do for me to simply state that the needle should be at the twelve o’clock position, for example, I would need to to demonstrate I knew why the parameter was chosen and be able to say what it was. 4 3 2 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted July 3 RMweb Premium Share Posted July 3 4 hours ago, Chris M said: I couldn't do the same today of course because you just can't get half inch ply It's called 12mm these days and still available. 1 Link to post Share on other sites More sharing options...
billbedford Posted July 3 Share Posted July 3 Is that 12 ± 0.5 mm? 1 1 Link to post Share on other sites More sharing options...
RMweb Premium PhilJ W Posted July 3 RMweb Premium Share Posted July 3 To be pedantic it should be 12.7 mm. 1 1 Link to post Share on other sites More sharing options...
Michael Hodgson Posted July 3 Share Posted July 3 1 hour ago, billbedford said: Is that 12 ± 0.5 mm? close enough for government work, as our American friends woud say. 2 1 Link to post Share on other sites More sharing options...
Deeps Posted July 3 Share Posted July 3 1 hour ago, billbedford said: Is that 12 ± 0.5 mm? No. It would be a half inch ± 0.5 mm🙂 2 6 Link to post Share on other sites More sharing options...
Chris M Posted July 3 Share Posted July 3 1 hour ago, billbedford said: Is that 12 ± 0.5 mm? My expertise in building baseboards means that it wouldn’t really matter. 2 1 4 4 Link to post Share on other sites More sharing options...
RMweb Gold franciswilliamwebb Posted July 3 RMweb Gold Share Posted July 3 38 minutes ago, Chris M said: My expertise in building baseboards means that it wouldn’t really matter. Same here. The 12 as much as the ±0.5 😉 3 3 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted July 3 RMweb Premium Share Posted July 3 The thickness of ply doesn't seem to be very constant. I've bought nominally the same stuff but with a 1mm discrepancy. 2 2 Link to post Share on other sites More sharing options...
pH Posted July 3 Share Posted July 3 3 minutes ago, melmerby said: The thickness of ply doesn't seem to be very constant. I've bought nominally the same stuff but with a 1mm discrepancy. I’ve found lumber dimensions gradually decreasing over time. The 4x4 timbers I’ve bought for outside construction in the garden have gone from 4 inch to 4 minus to 4 minuser. 2 Link to post Share on other sites More sharing options...
RMweb Gold Dunsignalling Posted July 3 RMweb Gold Share Posted July 3 3 hours ago, Chris M said: My expertise in building baseboards means that it wouldn’t really matter. I've seen some where +/- the half inch wouldn't make much difference....😁 4 Link to post Share on other sites More sharing options...
Hibelroad Posted July 3 Share Posted July 3 Ummm, has this morphed into a woodworking thread? Link to post Share on other sites More sharing options...
Deeps Posted July 3 Share Posted July 3 3 minutes ago, Hibelroad said: Ummm, has this morphed into a woodworking thread? Apparently this sort of phenomena is quite normal in rmweb. I feel sure someone will bring the thread back on line shortly, probably with a whacky sign painted on a piece of 12mm plywood. 2 1 2 Link to post Share on other sites More sharing options...
RMweb Premium Popular Post martin_wynne Posted July 3 RMweb Premium Popular Post Share Posted July 3 17 minutes ago, Deeps said: Apparently this sort of phenomena is quite normal in rmweb. I feel sure someone will bring the thread back on line shortly, probably with a whacky sign painted on a piece of 12mm plywood. When in doubt, there is always this one again. 1 3 18 Link to post Share on other sites More sharing options...
Popular Post jwealleans Posted July 3 Popular Post Share Posted July 3 5 16 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted July 3 RMweb Premium Share Posted July 3 28 minutes ago, Deeps said: a whacky sign painted on a piece of 12mm plywood. Or it could be ½"😁 4 Link to post Share on other sites More sharing options...
RMweb Premium J. S. Bach Posted July 4 RMweb Premium Share Posted July 4 8 hours ago, jwealleans said: IKEA?? 1 2 1 Link to post Share on other sites More sharing options...
RMweb Gold Hroth Posted July 4 RMweb Gold Share Posted July 4 14 hours ago, jwealleans said: Reminds me of 70s MFI flatpack furniture. 2 1 Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted July 4 RMweb Premium Share Posted July 4 6 hours ago, J. S. Bach said: IKEA?? No Allen key! 1 3 Link to post Share on other sites More sharing options...
luckymucklebackit Posted July 4 Share Posted July 4 14 1 Link to post Share on other sites More sharing options...
RMweb Premium melmerby Posted July 4 RMweb Premium Share Posted July 4 10 hours ago, Hroth said: Reminds me of 70s MFI flatpack furniture. After it's been in use for a couple of years............😄 1 1 Link to post Share on other sites More sharing options...
RMweb Premium PhilJ W Posted July 5 RMweb Premium Share Posted July 5 1 Link to post Share on other sites More sharing options...
KeithMacdonald Posted July 5 Share Posted July 5 On 03/07/2024 at 16:33, Hibelroad said: Ummm, has this morphed into a woodworking thread? It's warped. 2 Link to post Share on other sites More sharing options...
KeithMacdonald Posted July 5 Share Posted July 5 12 Link to post Share on other sites More sharing options...
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