Metric thread

We are changing.....

We are using both systems in the US. Look around, liters of soda, fasteners on vehicles, specs on many items, all metric (or both). The kitchen (recipes) is still not converting and 100 yards is the length of a football field. Kids are getting comfortable with both systems allowing a gradual adoption of metrics.
One thing that I dislike is C. for temperature. The F. system gives us a better feel for temperature. Ten degrees in C. is a much wider range than ten degrees F. C. is just too course, I think.
Hey, 80 cents a liter for gas might feel better than $3 a gallon!
 
Dave SHort is absolutely correct. Work in whatever sytem the drawings are in. This is the only rational way for engineers and machinists and other manufacturing operations. Don't convert; it leads to nothing but problems.

Bnhpr is also correct. Metric is inevitable, and if the US does not adopt it, we are doomed as a manufacturing country (of course, we don't manufacture much anymore anyway; mostly we are "service" oriented (think bulls-cows)). Do you all realize that the only countires in the world that still officially use Imperial measures are the U.S.A., Tonga, and one other small country?

You should also note that the metric world is not united either. SI is used in Europe, but in east Asia Japan, Korea, and probably China use striaght metrics. The only difference is that SI measures force in Newtons while striaght metric measures force in kilograms-force (kgf). By the way, in some countries in East Asia (Japan I know for a fact) is is illegal to own measuring devices calibrated in feet and inches.

The US Government defines two types of metric conversion: hard and soft. I don't recall which is which, but for purposes of this discussion , let's say hard conversion is changing to dimensions that are rational in the metric system, and soft conversion is to exactly convert current US standard sizes to metric.

Jerry Sharrett is wrong, the US is not resisting metric because of the spelling, it because of the massive cost of retooling to switch from Imperial to hard metric. I will give you one example: in wood construction, the US standard is studs an joinsts at 12", 16", 24", and sometimes 48". Plywood, oriented strand board, gyp board, etc. comes in 4'x8' or 4'x12' sheets. Acoustical ceilings are in 2'x2' or 2'x4' modules, and light fixtures are manufactured for these modules. Any carpenter, and most other people, can lay out framing and ceilings in these modlues without much thought. These modules do not convert to soft metric worth a damn: 12"=304.8mm, 16"=406.4mm, 24"=609.6mm, and 48"=1219.2mm. Panel sizes by soft conversion would be 1219.2x2438.4mm or 1219.2x3657.6mm. It would be silly to use these dimensions in the metric system. Hard metric modules would be 300, 400, 600, and 1200mm stud/joist spacing with 1200x2400 or 1200x3600 panels. Ceilings and lights would be based on 600x600 or 600x1200 modules. This extends to stud and joist sizing where nominal size of a 2x4 would be 50x100 in hard metric. Imagine the cost if all of the US manufacturers had to throw out their current tooling and buy new for hard metric conversions. THAT is why the US has not converted to the metric system.

Mike Phillips
 
I bought my first car in 1983. Shortly before, I bought wrenches, both metric and SAE. I never gave a thought as to which was which. When I came across a 10mm nut, I used a 10mm wrench. It didn't seem so hard at that time.

Now, I make all sorts of parts and regularly deal with both systems.

Go build a computer some time. You will notice that when you put the hard disk in, you use a 4-40 screw, but when you screw in the CD Rom Drive, you are doing it with an M3x.5

As far back as I can remember, these two threads have co-existed in computer cases. Go buy a brand new Western Digital Raptor Hard Disk and it will have a 4-40 screw holding it in place. Get a brand new Blu-Ray DVD Drive and that will be held in with a M3x.5. Is there an advantage? Sure. You'd be well served to use the correct screw for the job at hand.

For those of you who think the SAE system is not on the way out, just go try to buy a bearing sometime and get on with the ID or OD in SAE. Good Luck. Bearings are metric now and that's pretty much the end of that story. You will pay a premium for a bearing with a 1" Inside Diameter. Get the metric one and it'll cost less. Simple laws of supply and demand. Theres just more demand for Metric.

Our US system has lived on because our production as a nation has been very high in the past. Since that is changing, we are more and more forced to move on to the more accepted system. Numerically, we are a minority in the world so it would make sence that we should accept the standards placed before us by the world majority.

Ask anyone at the shooting range how much powder I use in my ammo and they will say, "I don't know". Not because I didn't tell them, but because I weigh my powder in grams, not grains. Why do I do this? Well, because all electronic components are made with the metric system in mind and scales of today are all made to be more accurate in grams. (because they use Grams as their native measure) They all do a math conversion to measure in grains so there is rounding error when measuring in grains. Hmmpf, immagine that. Damn near every person I know who's been told of this ignores the message. I've said countless times that scales measure in grams, and that there are 3 graduations metric for every 2 SAE, yet, they continue to use grains instead. Well, that means that their measuring error is 50% greater than mine... Duh... Do the math, accept that you will now shoot 4.100 Grams of powder, not 63.25Grains. Does 4.1 shoot more accurate than 63.25? Hell no, it's the same amount of powder. But the scale weighs it closer.

While electronics are different than manufacturing/metalworking, it's all the same. As for buying new tools, I have conversion charts so I can use the ones I have. A part made to 1.000" or to 25.400mm all measures the same to me.
Ain't the metric system great!
 
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Jay said:
We are using both systems in the US. Look around, liters of soda, fasteners on vehicles, specs on many items, all metric (or both). The kitchen (recipes) is still not converting and 100 yards is the length of a football field. Kids are getting comfortable with both systems allowing a gradual adoption of metrics.
One thing that I dislike is C. for temperature. The F. system gives us a better feel for temperature. Ten degrees in C. is a much wider range than ten degrees F. C. is just too course, I think.
Hey, 80 cents a liter for gas might feel better than $3 a gallon!
Click to expand...

Well, the good news is that they are the same at -40.
You think taxes are bad now, wait till Hillary has her way with us. :mad:
Orthographic projection is not a good subject to discuss here.

Feel the love
 
pointless

I still haven't heard a valid argument why the USA should convert to the metric system. As others on this thread have pointed out it's not a big deal to manufacture things to metric specs here in the land of plenty. We can make money doing it, especially if we're sending it to Europe. So what's the point of converting? To become part of the big global happy family? Why? The USA is a pretty new country and just think, we got to the top of the food chain in short order using which standard of measurement?? We didn't get to the top by doing what everybody else was doing. Did we? Are we going to stay on top by copying the standards of measurement and economic policies used by third world countries? I doubt it. If we keep going along with the trends, we're all going to be speaking Spanish, sleeping with our own gender, and worshiping Allah in a few short years.

gunmaker
 
Dave

Dave every half decent machinist can work on both systems, even an imbecil can learn, but you can't still get it. You are a sad case. I rest my case

Shoot well
Peter
 
"We are the World" and "Cumbia". Can you say,"one world government"?

Why has the U.S. dollar been in decline? Can You say "Amero" It's not just a political move, the powers that are really in charge (read, Money folks) that seek a world of fascism, want it this way. The total enslavement of Man kind is the agenda.

Why else would the one time strongest country in the world loose nearly all it's manufacturing and allow illegal workers into the country?

Why has it been necessary to take firearms away from people the world over, why do they continue to try in America?

Why do you get the same old crap from the politicians decade after decade.

Remember it was the tax law changes in the 1950's that started the climb of corporate America and brought about the end of the family owned business.

When you have the answers to the above questions, it not hard to understand, why.

Think about the origins of "Political Correctness" and why it's such a powerful tool in the hands of the elite and their lackeys.

Freedom of speech, has been effectively drowned. :mad:
 
gunmaker said:
I still haven't heard a valid argument why the USA should convert to the metric system. As others on this thread have pointed out it's not a big deal to manufacture things to metric specs here in the land of plenty. We can make money doing it, especially if we're sending it to Europe. So what's the point of converting? To become part of the big global happy family? Why? The USA is a pretty new country and just think, we got to the top of the food chain in short order using which standard of measurement?? We didn't get to the top by doing what everybody else was doing. Did we? Are we going to stay on top by copying the standards of measurement and economic policies used by third world countries? I doubt it. If we keep going along with the trends, we're all going to be speaking Spanish, sleeping with our own gender, and worshiping Allah in a few short years.

gunmaker
Click to expand...


In summary, my argument for conversion is simply based on efficiency. I commonly work with both systems, and find that we can be more efficient in S.I. metrics. Efficiency, breeds reliability, time savings, which, in the end, affect cost.

In the global marketplace we are loosing this race to smarter, harder working and more efficient people.

And when we lose our financial leverage on oil and technology.....it's gonna get ugly.
 
Geez

As the owner of a Industial Machine Shop, (Marine Repair), and a Machinist for my entire adult life, I can say that we are comfortable working within both systems. But, the vast majority of our work is with the 'inch" system. Even when we recieve prints and drawings that are in Metric, we do the conversions that allow us to use our standard inch measuring tools.
Where we do run into trouble is with threads. On occasion, we will encounter a large shaft with a metric thread on the prop end. Since none of our larger lathes will cut metric, we will have to farm out the work if we have to make a new nut, or something to the such. We have, at times, just turned the thread down to the nearest American Standard and put a corresponding American Standard Thread on it.
We did this a while back. A large propellor shaft that had originolly been machined in Japan had a galled thread on the prop end. The thread was in the neiborhood of 8 inches diameter. We just cut it down to 7 3/4 4 tpi, and made a new nut. As we say in our game, nobody but the fish and crabs know that the thread is not metric anymore.
There seems to me a lot of 'venom' flowing about this subject. Heck, you would almost think we were talking about something important, like 40x's or Savages.
That being said, some of the posters in this thread need to learn that rude behavior and discourse is just that, whether you are right in your beliefs, or not. It is just as easy to get your point accross without being crass and impolite.......jackie
 
you never know who's looking when you want to convert to SI. here's one that wants to convert now:eek:

americanflag.jpg
 
American workers

Bnhpr,

I just have to disagree with your statement that---
"In the global marketplace we are loosing this race to smarter, harder working and more efficient people."
It has been my experience that this is just not so.

I have spent weeks with engineers and toolmakers from China and Portugal and have friends that have worked in Japan for the last four years.
They came home for Christmas and we got to spend a day together.

From what I have seen and what I have been told, the American worker can compete with ANYONE from ANY country on ANY level.
We(American workers) can't however in most cases have much of an impact on the management in place in our companies.
I think THIS is were we are lacking ( I know it is) and many times like everything else, the little guy takes the hit.

I am old enough to remember the CEO of GM for instance saying"big cars are big money,small cars are small money" and "Americans don't want small cars."
What do you think of that statement now??
Point is the worker bees don't call the shots and when bad decisions are made well, just blame Joe lunchbox.
Consider what has happened in recent times when a CEO has been givin the boot---they still get their huge salary,their bonus, their pension, and their golden parachute.
Joe lunchbox just gets fired.

The product of any company is greatly affected by what management wants--what the powers that be want to produce.
If they want to produce a high quality product, rest assured that any worker that can't produce the desired results will be looking for another job.
It's a fact that maximum profit and bad calls have affected American companies much more then Joe Lunchbox.

Consider that the average American CEO makes ten (10) times what his counterpart makes in other developed countries.
Also, I have heard some very interesting comments (while on the job) by management people from other countries.
One of my favorites---" We love building cars in America---great workers,fairly low wages and third world benefits".
Management sets the tone and the parameters in any company.
Like another CEO from GM liked to say,"we are in the business of making money, not cars."

When Japan got a foothold in this country, they were building state of the art manufacturing facilities to build their cars.
GM was producing 1980 something cars on 1957 assembly lines.
Joe Lunchbox had nothing to do with it.

Rich
 
I have noticed that despite the cogent arguments to maintain inch measurements, a number of thoughtless forum members are still quoting their rifle calibres in metrics.
 
GUYS get serious

I appreciate the lot of you for your individual input and voicing your personal opinions. It doesn't take a genius to figure out that we all had some personal views on the issue. I didn't ask anywhere or anybody how big or how small, how accurate or how loose some genius is able to fit the thread or how your two nuts or half nuts bang and rub together and if or how you'll cut them off when you will not need them anymore. I'm quiet sure that probably all of you cut both (threads) at one time or other. The KEY WORD of the subject was SIMPLICITY of the METRIC as it comes and reads in even (rounded) straight forward numbers. There was nothing more or nothing less. If we all happen to differ so be it.

Shoot well
Peter
 
jackie schmidt said:
As the owner of a Industial Machine Shop, (Marine Repair), and a Machinist for my entire adult life, I can say that we are comfortable working within both systems. But, the vast majority of our work is with the 'inch" system. Even when we recieve prints and drawings that are in Metric, we do the conversions that allow us to use our standard inch measuring tools.
Where we do run into trouble is with threads. On occasion, we will encounter a large shaft with a metric thread on the prop end. Since none of our larger lathes will cut metric, we will have to farm out the work if we have to make a new nut, or something to the such. We have, at times, just turned the thread down to the nearest American Standard and put a corresponding American Standard Thread on it.
We did this a while back. A large propellor shaft that had originolly been machined in Japan had a galled thread on the prop end. The thread was in the neiborhood of 8 inches diameter. We just cut it down to 7 3/4 4 tpi, and made a new nut. As we say in our game, nobody but the fish and crabs know that the thread is not metric anymore.
There seems to me a lot of 'venom' flowing about this subject. Heck, you would almost think we were talking about something important, like 40x's or Savages.
That being said, some of the posters in this thread need to learn that rude behavior and discourse is just that, whether you are right in your beliefs, or not. It is just as easy to get your point accross without being crass and impolite.......jackie
Click to expand...


Jackie,

How do you get those intermediate sized props off? Do you hook up a high pressure hydraulic pump into a port into the taper, and break it off with it?

I know it's off the thread topic, but I had an idea for a barrel/action interface, where the barrel was fit to the action with a taper or taper/thread arrangement. This would create a very stable connection between the barrel and action, without having to tighten the heck out of it.

Have you ever heard of anything like this?

Ben
 
Bnhpr said:
I know it's off the thread topic, but I had an idea for a barrel/action interface, where the barrel was fit to the action with a taper or taper/thread arrangement. This would create a very stable connection between the barrel and action, without having to tighten the heck out of it.

Have you ever heard of anything like this?

Ben
Click to expand...


... tightening the heck out of a normally threaded and shouldered barrel is absolutely no problem...


Tapered threads would be a headache to do... and shortening the chamber and adjusting headspace would be a real pain as well... and I suspect it would not shoot as well as a tightly shouldered barrel...the headache to do would be the biggest problem I think...
 
Dennis Sorensen said:
... tightening the heck out of a normally threaded and shouldered barrel is absolutely no problem...


Tapered threads would be a headache to do... and shortening the chamber and adjusting headspace would be a real pain as well... and I suspect it would not shoot as well as a tightly shouldered barrel...the headache to do would be the biggest problem I think...
Click to expand...

Sorry for the confusion, the threads would not be tapered. The taper and threads, two separate entities.

The connection would look the same as a traditional action/barrel, only instead of a square shoulder, you'd have a 5-10mm long high angle taper, that's all, just a stupid idea.
 
It has been done but with a 30 degree angle for the barrel shoulder. It works just fine but requires some fixtures for measurment. It is more rigid but, when it's possible to build 1/8 moa rifles with a square shoulder, it's hard to justify the extra effort.
In support of the greater rigidity claim, we used to make some largish hydraulic dump cylinders at a shop where I worked. As I recall, they had a 6 foot stroke with an 8 inch bore. The cylinder rod was five inches in diameter with a 2 1/2 inch tenon. Because the piston was relatively short (about four inches) it was able to rock a bit and we had trouble with the rods breaking off at the shoulder of the tenon. I started fitting the pistons with a 45 degree shouldr and seat and the breakage problem was a thing of the past.
By the way, fractional (binary?) sizes are used frequently in machine work. Centerless ground shafting comes in 1/16 inch sizes. O rings are sized in 32nds. So 3 and 7/16 shafting is a standard size.
How likely do you all think it is that the 303 British was conceived as a 5/16 bore (.3125) or the .375 as a 3/8? It just seems likely the British would have tried for that Imperial size!
Metric is fine but I still can't visualize sizes in metric until I convert them to inches. Regards, Bill
 
There is one vary welcome thing about metric. Bunches of in between sizes in drill bits. Sure can save your bacon in a pinch.
 
Ben

There are designs that do feature a hydraulic installation, and removal. They are keyless. The only draw back is if, for some reason, the fit will not hold the pressure, and you can't pump it up.
The vast majority of large props are on a tapered fit, either 1-12 or 1-16, with a key. It is held secure on the taper by means of a large nut.
For instance, a typical 8 inch diameter shaft will have a taper fit that is 18 inches long, 1-12 taper, or "one inch taper to the foot", with a 2 inch wide keyseat. The thread that is used to secure the prop will be in the vacinity of 5 inch diameter, 4 tpi, 6 inches long. Shafts under 6 inch diameter will have a taper that is 1-16, or "3/4 inch taper to the foot".
Installation for most is hammering the nut up as tight as possible, (20 pound sledge hammer on a big slugging wrench), and then heating the prop hub up to about 300 degrees, and re-hammering the nut. After it cools, the slug the nut again, and lock it with a welded strap.
To get them off, they heat them, and use a big 100 ton jack with a "strong back", and pull bolts in the hub to apply the tonnage. Or, at least that is the correct way. If the pull bolt holes are all messed up, or the jack is in the shop, or the crew just doesn't feel like dragging it all out, (this IS a shipyard), they just heat the prop up, and "beat it till it bleeds". Crude, but affective.........jackie
 
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