#10 screw and 3/16 screw

[oldtiffie]

OK - now convince the rest of 'em

OK - you've convinced me - now convince the denialist anti-metric brigade who don't/won't/can't see any use for or use metric at all.

I didn't claim to be special at all - just an ordinary one of a large group of the great unwashed in metricated countries and industries.

As I said, it seems to me that the metric people are more acceptable/adoptive of/to inch than the "inch" users are of metric.

[Uncle O]

It seems that as a general statement of what seems to be case here, that those of us in "metric" countries (most who "grew up" with "imperial" and adopted and adapted to "metric") accept and use and work in and with "imperial" every day of the week.

Its almost if as we are bi-lingual in that sense as we are quite comfortable working with both systems.

Many in the US seem to be "in denial" that metric even exists let alone is used and useful by anyone (else) anywhere (else).

The US is quite free and within its rights to "stay imperial" and most of the metric world is quite prepared to let it - as it should.

I have quite a few tools that are "inch" - dial indicators are good case in point - that are calibrated to 0.0005" ("five tenths" or "half a thou"). As 0.01mm is precisely 0.0003937" is is more than good enough to say the 0.01mm = 0.0004".

It is easy to see by eye - without any conversion that "half a thou" (0.0005" = 1 1/4 x 0.01 = 1.25 x 0.01 ~ 0.0125mm - or put another way 0.01mm ~ 0.0004 ~ 4/5 x the 0.0005" calibration.

I can work just as well using metric indicators and converting to "inch".

The best and ideal way of course is to use digital tools (micrometers, DRO's, calipers etc., set them to your dimension and system of choice and then press the "in/mm" conversion button and there you are - instant conversion.

My bet is that the trade stockists in the metric countries have a better "inch" range of product than the "inch" country (USA) has of "metric" stock.

This entire post is laughable....who said we don't/can't use both Imp/metric
daily ? It is nothing to convert one to the other or switch the machinery over to read one or the other. What ever gave you the idea that you were so special ?

[tyrone shewlaces]

Ssshhh Tim,
Don't let on that old Joseph who set the first standards up before American was even found and used 55 degrees with rounded roots and flanks is still the strongest thread form to date.somewher

Now see there ya go braggerin' er sumthin'.
So 55 degress is stronger and the rounded root & flanks is stronger. No argument from me there. But is 55 the magic number? Maybe 54-1/2 is even stronger and 55 degrees is just a lazy cop-out.
So going 60 degrees is a lazy cop-out to begin with. Those rounded root and flanks is what you get after a bit of production dulls the tool anyway, so no need to spec it. Management cost-savings. Cop-out.
A Whitworth form of some size will fit somewhere inside the cross section of a 60-degree V after all. It's in there somewhere.
Technically 60 degrees is 1/3 of an about-face. It's that fraction thing again I think. We like fractions here.

In actuality, just making a bolt bigger than needed will do fine, and does, unless weight is an issue. So do they use Whitworth in Aerospace? Probably should. Probably don't.
60 degrees is metric and metric is all scientific and aerospace is all scientific too. Probably just metric fasteners. Another cop-out.

But as my pappy always said - "If it weren't fer half-assed, nothing would ever get done."

[jdunmyer]

I, too am beginning to love the standardization of Metric. Sunday, I made a new jet for a snowmobile carburator. First thing was to figure out what thread it was, assuming metric, as it's a Yamaha from Japan. Hmmm... looks to be about 5mm. Check my Metric tap & die set to see what thread it might be and find....let's see....can it be? Yes, I have FOUR choices in a 5mm size: .75, .8, .9, and 1.00 pitch!

God only knows how many different 5mm threads there'd be if Metric wasn't so standardized.

[oldtiffie]

Use it or lose it.

It seems that as a general statement of what seems to be case here, that those of us in "metric" countries (most who "grew up" with "imperial" and adopted and adapted to "metric") accept and use and work in and with "imperial" every day of the week.

Its almost if as we are bi-lingual in that sense as we are quite comfortable working with both systems.

Many in the US seem to be "in denial" that metric even exists let alone is used and useful by anyone (else) anywhere (else).

The US is quite free and within its rights to "stay imperial" and most of the metric world is quite prepared to let it - as it should.

I have quite a few tools that are "inch" - dial indicators are good case in point - that are calibrated to 0.0005" ("five tenths" or "half a thou"). As 0.01mm is precisely 0.0003937" is is more than good enough to say the 0.01mm = 0.0004".

It is easy to see by eye - without any conversion that "half a thou" (0.0005" = 1 1/4 x 0.01 = 1.25 x 0.01 ~ 0.0125mm - or put another way 0.01mm ~ 0.0004 ~ 4/5 x the 0.0005" calibration.

I can work just as well using metric indicators and converting to "inch".

The best and ideal way of course is to use digital tools (micrometers, DRO's, calipers etc., set them to your dimension and system of choice and then press the "in/mm" conversion button and there you are - instant conversion.

My bet is that the trade stockists in the metric countries have a better "inch" range of product than the "inch" country (USA) has of "metric" stock.

[Peter N]

Really , we just don't care.

Of course you do, otherwise you wouldn't have posted that.

[Uncle O]

Really , we just don't care.

[John Stevenson]

Ssshhh Tim,
Don't let on that old Joseph who set the first standards up before American was even found and used 55 degrees with rounded roots and flanks is still the strongest thread form to date.

.

[Timleech]

A 9/16" bolt uses a 9/16" wrench right?

It does if it's Whitworth

Tim

[JCHannum]

There has been enough demand for them to now make R8 tapers with M12 drawbar threads instead of 7/16" UNF because many countries don't have a clue what UNF is.

No big deal, NMTB taper tooling has been available with Imperial and Metric threads for years. It is a matter of use.

I will make a WAG that 9 out of 10 consumers in any country neither know or care what threads a given piece of equipment uses. It is only a very few, such as ourselves, who even know what the various threads are. To most, they are big or small or maybe medium sized.

A 9/16" bolt uses a 9/16" wrench right?

[John Stevenson]

The problem is that switching to metric takes tons of cash for tooling, so demanding that the manufacturing behemoth the US once was to change to metric because some French wussy, bottle-glasses Beaker scientist could then just move the decimal instead of having to remember a conversion factor just wasn't going to happen.

.

That sums it up "the manufacturing behemoth the US once was"

You have no control over imports.

Why not insist that all Grizzly machines ship in with UN threads ?

Will the new South Bend have UN series threads?

BTW I'm not saying that one system is better than another all I'm saying is that you need to look around and see what others are doing.
Who else uses the number thread system for threads below 1/4" in the world ?

You are buying in imports designed in metric but who wants to buy imperial exports in todays multi national world ?

Look at this.

http://www.ctctools.biz/servlet/the-Tool-%26-Work-Holding-cln-ER-Collet-Chucks/searchpath/18225/start/73/total/82/Categories

There has been enough demand for them to now make R8 tapers with M12 drawbar threads instead of 7/16" UNF because many countries don't have a clue what UNF is.

.

[S_J_H]

I think it just boils down to what you were brought up using. I have used imperial since I was a kid so my mind naturally works in imperial units MUCH easier. I can instantly envision a 1/2-13tpi bolt in my head like a picture. But if I try and envision a 12mm 1.75 pitch I have trouble.
Given a lathe that cuts all threads, I always will select a imperial thread for my projects just because I get all warm and fuzzy and stay in my comfort zone.

Any real Hardware store in the U.S. has a decent bolt section with coarse and fine selections for imperial. Most will have a good selection of metric fasteners as well.
Again, If I am cobbling up something and need fasteners for the project I always choose imperial. It has nothing to do with which is better, just sticking with what I know best.

Old dog, old tricks right?

Steve

[spope14]

Did anyone mention that 3/16-24 is a very close 10-24 thread? Same thing pretty much except for the major diameter for the 10-24 on an OD thread is .1890 for the high limit class 2, Machinery's handbook ed. 24. The only real change being about .0025 on the OD thread allowance, the 3/16 being a bit smaller by that much for the high limit.. Found a 3/16-24 in a very old machinist textbook in my library finally. I would wonder about the loseness, the 10-24 tap may be an H3 type? The H shows your "oversize" cut allowance.

[SDL]

They're still pissed that they got beat by a bunch of colonial hicks.

NO Were pissed you needed the help of the French

Steve Larner

[tyrone shewlaces]

So two standards ?

No. One standard with fine and course pitch. Metric has fine and course as well. Metric and imperial both also offer "special" threads but that's just stupid in most cases and we won't go there. No advantage of one over the other. The problem is that switching to metric takes tons of cash for tooling, so demanding that the manufacturing behemoth the US once was to change to metric because some French wussy, bottle-glasses Beaker scientist could then just move the decimal instead of having to remember a conversion factor just wasn't going to happen.

Send the lad out for a M12 bolt and he'll come back with a M12 x 1.75 bolt.

Yea and over here he'll bring you a 1/2-13. If you want fine pitch, then you'll have to send him back a second time.

I don't see why anyone thinks there's such an advantage to metric. The metric bolt notation even looks clumsy to me. Ever screw up and read 1.25 to be 1.75 for a pitch and vise-versa? That's the problem with metric. You want to be lazy and just move a decimal place? Fine. Now you have decimals in everything because you aren't allowed to just divide something up anymore. Especially if it's thirds or something. Oh God - Blasphemy! 1/3rd of a centimeter? Unheard of! Why? (I think the American engineers picked 13 for the pitch of a 1/2" bolt just as a jab to the metric fans. "1/13 of an inch? Is that even allowed?" hehe.)
I think people who love metric are the same type who hate fractions or something. US units are good for learning fractions. Units are supposed to be something divided up to begin with right? Whomever limited the divisions to only 10 was just short-sighted. Why not be able to divide something into whatever unit is the most useful instead of arbitrarily picking 10? THAT'S right - I called metric "arbitrary" and I meant it.

If a guy is not good with numbers, he's not going to be much good in either system. He'll be able to blame the "other" system though, so he's got that going for him.

The world will NEVER settle on a single standard I don't think. Unless metric could include the two most universal units in the universe, it will never take off. I'm speaking, of course, about the units of HH and FF. These are used more than any other unit in history and their intuitive relationship to all things is apparently undeniable. It's the newscasters' standard measure and the abbreviations of course stand for Human Hair and Football Field.

This silly "metric system" thing doesn't stand a chance.