Member postings for Harry Wilkes

I'm not sure this is true, at least in Britain it's still pretty common for young people (who do anything remotely practical at all) to have good familiarity with both imperial and metric systems, and to be able to convert between the two freely.

Most of us* prefer metric, but as long as America exists we have to be conversant in both and the US influence on young people has if anything grown as a result of the internet making "the pond" a lot smaller in people's digital lives.

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When you get to young people who are being trained in engineering occupations, unit conversions are still considered a fundamental skill they love to drop into the curriculum to catch people out at every level right up to people doing MSc/MEng... At least for people in the process industries.

Because in real life you have to work with systems that were designed anywhere from 1840 to the present day, and built all over the world.

So you may well find yourself having to modify or integrate with an assembly originally built when your grandfather was your age, which now has different components specified by long since defunct OEM's in SI, CGS, US Customary, Imperial, and drawn to three or four different standards.

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That latter point is why I don't get why metrication of the hobby really matters... In real life the existence (and continued promulgation by Americans) of the imperial system is just something you deal with.

*Yes, I'm claiming to be a young person, but being early 30's that statement is somewhat relative.

Edited By Jelly on 08/03/2023 12:36:01

I'm not sure this is true, at least in Britain it's still pretty common for young people (who do anything remotely practical at all) to have good familiarity with both imperial and metric systems, and to be able to convert between the two freely.

Agreed that's what I suggest earlier but they were described as being 'very bright'

H

Not at all, it's a complicated subject deserving attention, even if we have our ideas rejected!

Standardisation of Weights & Measures has a long and difficult history. A story of order versus chaos, conservatism vs progress, practical vs theory, me vs us, local vs national, and national vs international. And a potent symbol of who is in power, which is why ambitious politicians fostered the impression that Metric was foisted on Brits by the EU. A fib.

It was recognised early that different measurement systems are an obstacle to trade. In medieval times ordering a 'yard' of cloth caused short-changing or over-provision because the suppliers yard was different. The differences were exploited ruthlessly by dishonest traders.

Imperial is the result of many painful rationalisations over centuries. They often had to be enforced by the King sending the boys round to 'explain' the need for change, and the conversation often ended in violence.

A tailor trading in Truro sees no advantage in dumping great-grandad's yard, which works perfectly well for him, and he's not going to cooperate just because the whole country poorer as a result as a result of trade problems. Not a problem in Truro that Baltic merchants can't trust English cloth measure, so our tailor resists. He calls on tradition, politics, propaganda, and deploys fear, uncertainty and doubt to delay and prevent change. His motives are personal and local, and ignore wider benefits that don't apply directly to him.

Imperial as we know it is a product of 19th Century efforts to deal with the Industrial Revolution struggling due to duff weights and measure. To reduce bother, they built on traditional foundations. The root was the yard, pound, and second, heavily embellished with hundreds of size units, related by odd ratios determined in the past. So we have grains, drams, ounces, pounds, stone, hundredweights, and tons, and the ratios are inconsistent, so although a dram is 1/16th of an ounce, there are 27.34375 grains in a dram. There are 16 ounces in a pound, 14lbs in a stone, 7.142857 stones in a Hundredweight, and 20cwt in a ton. Length measure also has many multi-ratio relationships.

Fairly obviously I hope, these conversions complicate Imperial calculations. Just because the resulting confusion may not apply to us individually (in our local home workshop), does not mean everyone is well-served by Imperial - far from it.

The big trouble with Imperial starts when derived units are needed. In mechanics these are: Energy, Force, Frequency, Power, and Pressure. Although man-in-shed engineering rarely calculates in them, they are fundamentally important to anything other than basic engineering design. Inches and thou are fine when building a steam locomotive to a plan, because deciding how strong the boiler needs to be to operate safely at a given pressure was done by someone else, a mathematically trained engineer. I worry about him because although the maths can be done in Imperial measure, it's hard work. Imperial measure is a poor tool for advanced work in science and engineering. It's odd that some model engineers deliberately favour a poor tool!

Whilst Victorian legislators were corralling Britain's chaotic traditional measures into Imperial for commercial reasons, the scientists had gone a step further. They had realised a century before that it was feasible to design a coherent system of weight and measures. (Mostly coherent - it can't be perfect.) That is, a system where units are logically related, and there are no random ratios between them. The system supports domestic needs whilst greatly simplifying difficult calculations. Not a cosy change; a coherent system requires most historic measures to be abandoned, and this trampled on the delicate feelings of traditionalists and everyone who had painfully learned to calculate in Imperial! Old dogs don't like learning new tricks. So there was an immediate, powerful reaction against metric, derided as 'foreign' by British vested interests, even though British brains were in the forefront of the new system.

Personally, I think it's a mistake to mix politics, emotion, tradition with engineering and science. When a better tool becomes available, engineers should use it. Essential in brutally competitive manufacturing. Chaps who held the firm back by insisting on Whitworth, Imperial measure, old-fashioned methods, and Spanish practices, thought small-c conservatism made their lives easier: actually, it was one of the reasons that so many 'solid' British engineering companies went to the wall.

Lesson learned - don't lumber future engineers with inferior methods just because they happen to suit me.

In my humble opinion, Imperial has been a dead-weight for well over a century. Like smoking tobacco, people love it, but the habit is harmful. So, are you a Truro Tailor or a thrusting industrialist planning for 2030 and beyond? Does anyone really believe Imperial measure will be an asset to British engineering when we are all dead?

Dave

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Really? Even after slugs were explained? They must be very bright...

Dave

Of course they are give them a drawing and they can work in either imperial or metric ! Also I would suggest one needs to be bright to be a model engineer

H

J reveals a misunderstanding of fits and tolerances I fear!

'You can pretty perfectly gauge an amount of slop in a slip, or an amount of welly on an interference in a handful of thou.' isn't working to a tolerance, it's "Fitting" in the old fashioned sense. This is not working to a tolerance, because that requires dimensions to be measured carefully. Measurements must done with a micrometer, with go-no gauges, jigs and fixtures, or calibrated machines, never 'judged by eye'.

Old-fashioned fitting is how I work. The system uses the work itself as a series of gauges, each part being trimmed to fit into another. Accurate measurement isn't required, and stuff can be judged by feel. Fitting works in any system of measure, Uncouth can believe I'm lying if he wants, but I do the same as he does in metric.

Fitting is great for home-workshops and repair work, but it fails miserably for production work. First problem, is that fitting is hideously expensive because the work is both skilled and labour intensive. Chaps who do it burble on about 'quality', but never mention productivity, which is rock-bottom. Worse, fitted components aren't interchangeable. If the parts from 20 PottyMill engines were scrambled and re-assembled, it's unlikely that any of the engines would work, and those that do are luck rather than engineering.

Interchangeability is achieved by setting tolerances and knowing for certain that all the parts are accurately machined to fit together by design. Parts made at different times and places can be brought together and assembled without 'judging slop with a slip'. If that's necessary, something has gone horribly wrong.

Fortunately interchangeability is rarely important in home-workshops. It's why I don't own any slip gauges, or anything better than a 0.01mm micrometer. I've even experimented with making stuff using plain calipers as comparators only. Works surprisingly well with care. The method knows nothing of 'thou': it's all done by feel.

Perhaps the worst feature of Imperial is it seems cuddly friendly at first. But first contact is misleading. It's rather like discovering the house of your dreams is built over a 200 fathom deep mineshaft full of chemical waste. All you have to do is ignore a few cracks in the walls and an occasional hint of Phosgene in the kitchen.

My point is purchasers might do better to buy an equally good house that doesn't have faulty foundations. Even if you personally don't understand a survey full of weird technical terms!

Always good to tilt a debate on it's head. As Duncan says, none of the world's metric users sees any advantage in Imperial. The only reason it's used is to supply legacy markets, almost never for new design. Imperial is gradually fading, even in the US.

Like it or not, Imperial measure is obsolescent. It's damaging to to foist it on the next generation. Don't stuff up the kids with Imperial, or any other old friends, when something better is available or time has marched on.

Dave

Sorry Dave have to disagree

It's damaging to to foist it on the next generation. why have you asked them ? We have to 2 young members in my club who are more than happy to work in imperial

H

Instead of buying a die I would buy a tap and run it into all the chuck backplates. I would be very wary of running a die down the spindle thread, you could easily wreck it, I would examine the spindle threads with an eye glass and very carefully stone any damage.

Big packets don't get lost as easily as little ones.

To true but they don't fit through the letter box when your not home

H

Did you guys ever consider starting your own Linux thread rather than giving us all the benefit of your "enlightenment" in every Windows discussion that takes place here? The question, as in other cases, was one about a specific Windows problem not a request for alternatives to Windows.

I get that you like Linux. Can you get that others are not interested in hearing about it at every opportunity?

Edited By Peter Greene 🇨🇦 on 21/02/2023 01:20:57

Peter why don't we not discuss Windows at all it is after all a model engineering forum