| General > General Technical Chat |
| why is the US not Metric |
| << < (185/291) > >> |
| cs.dk:
--- Quote from: tooki on December 23, 2019, 04:04:19 pm ---As for the yardstick: tue claim was that you could walk into any hardware store in Europe (i.e. not a specialist industrial tool vendor) and get dual-scale models. I think that’s untrue. --- End quote --- It may depend on the importer for that specific country.. I've personally never seen a metric-only Mitotoyo caliper, analog or digital. |
| bsfeechannel:
Well, guys, we are at that time of year when we try to forget our arguments and our differences and look on the positive side of life. This is when we reach out our hands to our fellow creatures and celebrate. Since the metric system is the epitome of that universal concordance, I can't help but wish everyone a Metric Christmas. Let's sing it together: We wish you a Metric Christmas, We wish you a Metric Christmas, We wish you a Metric Christmas, And a Happy New Year. |
| Tepe:
--- Quote from: cs.dk on December 23, 2019, 01:10:40 pm ---I wouldn't be surprised if Jem&Fix, Silvan, Bauhaus, or similar have them on the shelves. --- End quote --- I would :) Biltema, however, does have dual labeled "tommestokke". |
| KL27x:
It is easy enough to buy a metric-only tape measure in the US, online. But you won't have a lot of options, if any, in a regular hardware store. Most of my tape measures are combination. But one is imperial, only. It has the same 2^-1 graduations on both sides of the tape. It might be fun to have a tape with tenths or 20ths of inches on one side rather than 16th's. If you do any precision work in SAE, at least in my experience, you tend to think of it in decimal to thous. I.e. 1/8th steps are 0.125", .250", .375". .500", .625", .750", .875", 1.000" Each 16th is 62.5 thous. Each 32nd is 31.25 thous, or about 30. But we have digital calipers; if you need this kind of precision, you are not using a tape measure, anyway. There's something "good" about using thousands/ths (000-999's), like metric users have found. And the inch just is the right size for this in common machining and manufacturing. Hundredths of mm would be the closest scale, but you only get 100 of them and they are more than double the resolution (so you only cover 1/25th of the range before adding decimal points (or commas that are in the wrong place); also this resolution is beyond inexpensive calipers, so the accuracy tolerance adds additional baggage.) Using thousandths of cm has its own problems; it seems like no one does that. Size of the unit absolutely matters to the context of what you are doing, IMO. Look at it like this. If you handed an EE a caliper mechanism with no markings, just the electronics, and no measuring system existed, yet, and you ask him to make the thing show digits on it down to w/e resolution if has, he would have come up with something close to the order of thousandths of an inch. If you asked people to put useful markings on a measuring stick or tape to build things like homes and boats and boxes and baskets, well... that's how the inch evolved. The statute mile is a little weird. But, hey, the Romans built the best roads of their times, and it has worked out so far. They do what they are supposed to. At the top end of precision CNC, the situation is reversed. Today's best software in the realm of high precision machining goes down to the nearest thousandth of a mm. Not that the machines can make things to this precision. But it does make for potentially smoother (talking about surface finish at this point) curves and radii when the max resolution is used. ;;;;; A lot of the time in low tolerance production work, it is not efficient to use general measuring equipment, at all. You will make some kind of custom measuring thing, like a go/no-go gauge, to verify you are meeting the mark to the tolerances required, and to sort parts that are good, need further work*, or have to be binned. * This might mean running the parts through the exact same process, again; or maybe having to stop and tweak the settings to run a batch of oversized or otherwise out-of-spec parts when you have enough of them. |
| CatalinaWOW:
On a recent road trip I came across another little tidbit on the cost of metrification in the US. On one recently worked interstate highway all of the speed limit signs had been replaced with electronic signs which can be remotely changed to reflect current traffic conditions and the like. Since this is in Arizona, the state that already owns the only segment of interstate marked in metric this seems like an easy opportunity to cheaply convert to metric in the future, right? Not so fast chucko. The signs only support two digit numbers. So can only support a metric speed much lower than the current limits. Conversion will require adding a half digit to each of these signs (or would have required that additional expense this time around). Not an insurmountable barrier, but just another case where the conversion isn't free and one case where traditional units are actually better matched to the use case than metric. Few if any places anywhere in the world have allowed highway speeds in the three digit class using traditional units, but they are quite common using metric units. At least metric doesn't require a full third digit in very many, if any, cases. |
| Navigation |
| Message Index |
| Next page |
| Previous page |