4 ms·

a machinist told me that when he had to start doing metric stuff it was all the same dimensions, but converted to metric. so instead of 1/64" he had to mill 0.3

a machinist told me that when he had to start doing metric stuff it was all the same dimensions, but converted to metric. so instead of 1/64" he had to mill 0.396875mm. even if everything new designed was in metric with fairly round numbers, you still have a ton of existing stuff designed with imperial units that needs to be taken into account and designed around. the result in some cases is that you get none of the benefits from metric or imperial. and your machinist needs to buy new equipment. the main thing metric has going for it is that it's the same radix as our counting system and is consistant (as opposed to base12 and then base5280).

corty 6y ago
There are a few more advantages, especially when machining. There is a large system of standardized metric parts, e.g. washers, screws, etc. available on the cheap because they are needed everywhere. Whereas the US mess of screw sizes, denominations and threads produces a nonending headache of unavailability, high price and non-fitting but similar-looking parts. Yes, the changeover will be ugly and involve redoing all your plans at some point. But after that you will see how much you are missing out...
- 0BADAC1D 6y ago
  there's a bicycle suspension company that's all-metric except for a single screw to adjust tension. apparently the metric screws had too steep of threads and didnt allow for the level of fine adjustment they wanted. clearly we should create another standard to encompass all these cases and alleviate confusion.
  - corty 6y ago
    There is a standard for metric threads with a finer inclination/pitch, no need to create anything special for the purpose: https://en.wikipedia.org/wiki/ISO_metric_screw_thread https://en.wikipedia.org/wiki/ISO_metric_screw_thread
alkonaut 6y ago
> the main thing metric has going for it is that it's the same radix I think this is the thing that is usually lost. Metric isn't about the units. No one cares whether the length unit is the size of a finger or a foot. What's important is the radix, ease of conversion conversion and relation between the units of different dimension. A swimming pool can be 10m long and 5m and 2m deep. That means its volume is 100m^3 or 100 thousand liters and the mass of the water is a hundred tons. There are 3 coke cans in a liter (or kilo) so the pool could room 300k coke cans. Quick in-your-head conversions like that are so difficult in some cases with pounds, gallons, fl.ounces etc.

corty 6y ago

There are a few more advantages, especially when machining. There is a large system of standardized metric parts, e.g. washers, screws, etc. available on the cheap because they are needed everywhere. Whereas the US mess of screw sizes, denominations and threads produces a nonending headache of unavailability, high price and non-fitting but similar-looking parts. Yes, the changeover will be ugly and involve redoing all your plans at some point. But after that you will see how much you are missing out...

0BADAC1D 6y ago
there's a bicycle suspension company that's all-metric except for a single screw to adjust tension. apparently the metric screws had too steep of threads and didnt allow for the level of fine adjustment they wanted. clearly we should create another standard to encompass all these cases and alleviate confusion.
- corty 6y ago
  There is a standard for metric threads with a finer inclination/pitch, no need to create anything special for the purpose: https://en.wikipedia.org/wiki/ISO_metric_screw_thread https://en.wikipedia.org/wiki/ISO_metric_screw_thread

alkonaut 6y ago

> the main thing metric has going for it is that it's the same radix I think this is the thing that is usually lost. Metric isn't about the units. No one cares whether the length unit is the size of a finger or a foot. What's important is the radix, ease of conversion conversion and relation between the units of different dimension. A swimming pool can be 10m long and 5m and 2m deep. That means its volume is 100m^3 or 100 thousand liters and the mass of the water is a hundred tons. There are 3 coke cans in a liter (or kilo) so the pool could room 300k coke cans. Quick in-your-head conversions like that are so difficult in some cases with pounds, gallons, fl.ounces etc.