Nuts and bolts. SAE, Metric, or both

[T18skyguy]

I been wrenching on vehicles all my life. It use to be only SAE, then it became a mix of SAE and Metric. I thought they we're going to phase out SAE and go all metric at some point, but it seems like it's been a mix forever. I'm putting together a tool kit for my 2017 Greyhawk. Do I still need both SAE and Metric wrench and sockets? Are they ever going to switch over to all metric and be done with it? Tools are heavy I just wish there could be one standard.

[Matt_Colie]

Then there is the small problem that the base units of the original metric (French) were all in error.

The distance from the pole to the equator was never actually measured when they established the meter, just calculated based on bad French surveys.
The degree "Centigrade" => Now Celsius was supposed to based on temperatures of freezing and boiling of water and they did not use pure water and did not correct for atmospheric pressure. They also found out the "Centigrade" had been used elsewhere.
The Ton was established on a flawed unit of measure for the mass (not weight) of cubic meter of water. (Let's not go back there.) And a Gram is just 1/1000 of that.
A Newton that is the unit of weight or force, is based on accelerating and 1 Kg mass at 1 M/s.......

The US meter is now established as distance light travels in 1/299792458 of a second. It was changed from wave lengths of a Krpyton 86 lamp.

It all is really just more accepted than the English units, it is no better.

Matt

[MEXICOWANDERER]

400 Gradians I can see it now

[liborko]

1 millimeter is 1/25 of an inch.If you have full metric set next metric size is 1/25 of an inch larger than previous. Standard sizes increase in 1/16 of an inch increments which is bigger than 1/25.

9/16 is 14.287mm so if 14mm does not work 15mm will work for sure.
3/8 is 9.525mm so if 9mm does not work 10mm will work for sure.

If you use 15mm socket on 9/16 head it will be .028 of an inch oversize
If you use 10mm socket on 3/8 head it will be .0187 of an inch oversize.
Can you live with that?

If USA actually switched in 1905 to metric system when they accepted the system we would not have this mess today.

[pianotuna]

Thanks DrewE that was a nice knowledge nugget

[fj12ryder]

“A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines. With consistency a great soul has simply nothing to do...." Ralph Waldo Emerson

[Tom_M1]

Imperial vs Metric:

[DrewE]

pianotuna wrote:
Hi,

Sure why not just change to 400 degrees in a circle.

That would be 400 gradians or gons in a circle, a unit of angular measure that, like the metric system, was devised during the French revolution; however, unlike the Metric system, it has not been very widely accepted.

Quite a few scientific calculators have a gradian setting, in addition to degrees and radians, for their trig functions and now you know what that's all about.

[fj12ryder]

Tom_M wrote:

wa8yxm wrote:
The USA is the only country still using the Inch, pound, seconds units of measurements everyone else has gone to Meters, Grams, Seconds.

Metric seconds? Is that 100 seconds to the minute?

Courtesy of the French revolution:

"The main advantage of a decimal time system is that, since the base used to divide the time is the same as the one used to represent it, the whole time representation can be handled as a single string. Therefore, it becomes simpler to interpret a timestamp and to perform conversions. For instance, 1:23:00 is 1 decimal hour and 23 decimal minutes, or 1.23 hours, or 123 minutes; 3 hours is 300 minutes or 30,000 seconds. This property also makes it straightforward to represent a timestamp as a fractional day, so that 2018-11-25.534 can be interpreted as five decimal hours and 34 decimal minutes after the start of that day, or 0.534 (53.4%) of a day through that day. It also adjusts well to digital time representation using epochs, in that the internal time representation can be used directly both for computation and for user-facing display."

[Tom_M1]

pianotuna wrote:
Sure why not just change to 400 degrees in a circle.

Metric is in units of 10 so it would be 100 degrees.

[pianotuna]

Hi,

Sure why not just change to 400 degrees in a circle.

Tom_M wrote:

wa8yxm wrote:
The USA is the only country still using the Inch, pound, seconds units of measurements everyone else has gone to Meters, Grams, Seconds.

Metric seconds? Is that 100 seconds to the minute?

[fj12ryder]

MEXICOWANDERER wrote:
"And this here sucker looks close enough to a 9/16 th's --- that just a little English otter -- whoops! Dang. Where are those danged Vise Grips. Maybe I shudda got a real pair rather than these Panda Paradise brand"

Hell, I got the bolt snug enough but the teeth on the Vise Grips are pretty screwed up. Well what's the chances of me ever tangling with that bolt again?"

It's all a matter of an individual's perspective, gents...

Like the time an idiot drove into my shop with rounded off bolts holding his Delco 12-SI alternator on. I wrote an estimate that included new grade eight fasteners. He got ornery. I wished him the best of luck.

Wait a second, aren't you the one that posted about that fancy-dan pair of vice grips: Knipex Improvement On The Crescent Wrench

[Matt_Colie]

I was running a durability lab in the early 80's, What was real good was GM (a client at the time was changing from SAE to Metric. So, things that screwed into production major castings would still be SAE until the casting was revised. Everything else was Metric. Sounds easy - Right?
But there were two problems:
FEAD (Front Engine Accessory Drive) stuff often connected to other FEAD stuff and a block or head. Where it connected to a major casting it was "probably" SAE. Where it tied to another bracket, it was Metric. Unless the head casting was a new design (which was happening a lot because they were trying to reduce weight), then it might be metric.
Then there was the supplier issue. When they called for an 8mm fastener and did not specify, it was a toss-up if the supplied fastener was DIN or JIS and the pitches were different.
That has fortunately been solved by an SAE edict that describes all the fasteners as laid out ISO.

As it is for me right now, our coach is only SAE (being OLD), but I carry a set of tools for ISO too. That is just so I can help someone that may need it.

Matt

[mike-s]

fj12ryder wrote:

mike-s wrote:
0.5625 - 0.551 = 0.0115, not 0.010. It's simple subtraction, taught in grade school.

"Rounding means making a number simpler but keeping its value close to what it was." You can feel .010", one ten-thousandths of an inch is barely even perceptible. Geeze louise. And I thought I had the lead in pedantry.

Really? You gave a figure to 3 digits (and another to 4 digits), and now want to claim you rounded it to 2? YOU are the one who thought it important to give 4 digits of precision, not me. You really fail at math.

Oh, and rounding 0.0115 to 3 digits would be 0.012.

[MEXICOWANDERER]

"And this here sucker looks close enough to a 9/16 th's --- that just a little English otter -- whoops! Dang. Where are those danged Vise Grips. Maybe I shudda got a real pair rather than these Panda Paradise brand"

Hell, I got the bolt snug enough but the teeth on the Vise Grips are pretty screwed up. Well what's the chances of me ever tangling with that bolt again?"

It's all a matter of an individual's perspective, gents...

Like the time an idiot drove into my shop with rounded off bolts holding his Delco 12-SI alternator on. I wrote an estimate that included new grade eight fasteners. He got ornery. I wished him the best of luck.

[Ralph_Cramden]

fj12ryder wrote:
And I thought I had the lead in pedantry.

No, Not even close reading through these boards. They should rename this forum Pedantry.net LOL.