Metric thread

P

PPP MMM

Guest
It's a pity that all rifle actions are not made in metric. Standard M26X1.5, M28X1.5, M30X1.5 would virtually accomodate for any possible scenario. The gunmakers in Europe and Japan made the conversion from once imperial to metric without any hassle. Nice and easy, simple to measure and to work with and everybody be certain what the thread actually is. The American imperial threads are far way too complicated and difficult to measure. What something like 1.187" 20TPI supose to be? If one doesn't know the actual exact size, simlpe measuring is of little value. If there is a misprint and says 1.183" 20TPI one could have an unnecessary headache to figure out the real size eventually. With a metric thread one simlpe flick with a vernier or even a ruler would be enough for one to be right on the track.

Shoot well
Peter
 
Boo! - you can have your metric... pain in the ass if you don't have metric gears.

There is nothing hard about measuring an action and fitting a barrel successfully the way it is... some people try and fit too tight when a little loose is better. (V threads not square)
 
Major PIA to cut metric threads on my equipment. All my measuring stuff is in Std. Don't want to ever cut another metric thread on my lathe and sure don't want to buy all metric measuring tools too.
 
inch threads are more accurate

If you think about it the inch system of thread has to be more accurate than metric because of the incremental error stacking up from thread to thread. Kind of like resetting your odometer every time you stop your car and later add up all the numbers. Threading on a metric lathe is no real picnic either. Reason being it's not based around fractions. Inch threads are pretty dirt simple on a inch machine. Especially if it has a 4 pitch lead screw and the thread your cutting is a multiple of 4. Just grab the half nut whenever you want.
gunmaker
 
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I don't think that either system is superior or inferior to the other. Each is easy to work with and equally accurate, IMO. Yes, you are a lot better off working with the same thread system that your lathe is based on but that is something that is a problem for everybody.
I'll give you one thing, though. The fact that metric threads have their pitch designated by actual pitch sure beats having to divide 1.000" by the TPI to get the pitch.
Most problems associated with using the Metric system in the US is caused by people wanting to convert everything. Just think and measure in mm and forget about inches when dealing with metrics.
We all have opinions.

Jay
 
I have a hunting buddy who own a machine shop and he tells me a bigger percentage of their work is specified in metric every year. Kenny
 
forced metric

I might be a little outspoken on metrics being forced on the US population. Usually I argue with my mad scientist father about it every time I see him. There is a simplicity about the metric system that spooks me. Think about it. Your kid goes to school and in math class they say "Today we're going to learn the metric system. All you have to do is move that little decimal point one way or the other. Any questions class? NO?? Everybody gets an A today, class is out early." It replaces fractions to the degree that the brain gets lazy. The brain is like a muscle, the more you use it the better it gets. Kind of like buying your kids a calculator for a required grade school supply. If they don't have to think too hard, they won't. I'm not against the metric system in other countries. I just don't want it forced on me or my kids. I think we should get other countries to adopt the inch. How do you think they would like that?
gunmaker
 
Jay said:
I don't think that either system is superior or inferior to the other. Each is easy to work with and equally accurate, IMO. Yes, you are a lot better off working with the same thread system that your lathe is based on but that is something that is a problem for everybody.
I'll give you one thing, though. The fact that metric threads have their pitch designated by actual pitch sure beats having to divide 1.000" by the TPI to get the pitch.
Most problems associated with using the Metric system in the US is caused by people wanting to convert everything. Just think and measure in mm and forget about inches when dealing with metrics.We all have opinions.

Jay
Click to expand...

This is the whole thing in a nutshell. While it is true that more and more of our drawings are metric, it is nothing to get excited about. I quit converting some years ago, and just learned to deal with the metric system. Most machine controls, electronic measuring equipment, and machining software can be easily switched between the two systems. An easy way to visualize or quantify metric dimensions if you are used to the english system is to use these ratios: 1mm is very close to .040". 1.5mm is very close to 1/16".

As far as threading goes, there is little difference, except that mixing the two systems on a manual machine causes difficulties.......which if understood really are not that big of a deal. There really isn't any practical advantage to the metric thread, though....the basic lead/pitch and diameters are the only numbers that appear more straight forward....the rest of the math ends up carried out to the right of the decimal point anyway.

-Dave-:)
 
Metric vs. Imperial.

Folks there's nothing hard about going from Metric to Imperial or vice versa.

spend 30 bucks for a copy of Machinery handbook and every thread pitch imaginable is listed for you.

Including relevant pitch diameters, major and minor diameters, every dimension regarding a thread pitch is right there in B/W.

conversions are easy.

One millimeter is .03937" in length

25.4 millimeters make an inch.

Fresh batteries in calculators encouraged.

Enjoy!
 
NesikaChad said:
Folks there's nothing hard about going from Metric to Imperial or vice versa.

spend 30 bucks for a copy of Machinery handbook and every thread pitch imaginable is listed for you.

Including relevant pitch diameters, major and minor diameters, every dimension regarding a thread pitch is right there in B/W.

conversions are easy.

One millimeter is .03937" in length

25.4 millimeters make an inch.

Fresh batteries in calculators encouraged.

Enjoy!
Click to expand...

Chad,

First, Thank you for your service. My family prays nightly for those who are somewhere other than in the comfort of their home, with their family, for the good of the rest of us.

This thread started out about using all metric threads instead of what we are all used to. Jay pointed it in the direction that we're better off to just learn metric, and use it when necessary. I decided some years ago that converting was counterproductive for many reasons, and just learned to use which ever system the job was drawn to. Once used to it, I wished I'd given in sooner.

I'm with you on the Machinery's Handbook.............having a machine without owning the book is kind of like painting your windshield black and scraping a little opening just in front of your eyes. Just to prevent sticker shock, though, You're a little off on the price..........it goes for nearly three times that thirty bucks.

-Dave-:)
 
Well done Chad

At last someone here is able to understand the whole concept of this silly saga. In my original Post I wasn't complaining if it is hard or not to make and fit the thread, but to be able to measure the actual thread with something as stupid as a bricklayers ruler. It doesn't take genius to figure out that to fit a thread properly one needs to take the same care regardless of what the thread is called. You can measure metric with a ruler because it comes in total figures such as 5, 16, 20, 24, 30 x the pitch in mm. To go back to my original post and one can see that my example of Gilkes thread 1.187" 20TPI would be much harder to measure exactly and most definitely not with a ruler. If the same size was a metric it would be called M30.1498X1.27mm. If one of you know someone who would be able to measure that thread with a ruler, please let me know, as I want to be second to know him too. To say it simply the metric is epitomy of simplicity the imperial is the epitomy of complexity, however both can be made to the same exact tolerances, the size of the material is the same only the name is different, or is there someone here who is going to argue that his imperial micrometer is more accurate then mine with a metric thread? Give me a bucket.

Shoot well
Peter
 
PPP MMM said:
To go back to my original post and one can see that my example of Gilkes thread 1.187" 20TPI would be much harder to measure exactly and most definitely not with a ruler. If the same size was a metric it would be called M30.1498X1.27mm. If one of you know someone who would be able to measure that thread with a ruler, please let me know, as I want to be second to know him too.
Click to expand...
Shoot well
Peter
Click to expand...

Most folks would use a thread pitch gage for either Metric or Unified threads.............what is the big deal about measuring with a ruler, anyway?

-Dave-:):p
 
Ppp Mmm

If you take a scale that is marked in 32nd/16th and measure 1.187" there is no problem measuring it. And by the way 1.187" used as a fraction, just as a even metric would be, is 1 3/16" or 1.1875". If you use the right tool for the job there is no probllem with either thread system(except on machines that are a lot of trouble to set up for metric).
Glenn
 
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bglenn said:
And by the way 1.187" used as a fraction, just as a even metric would be, is 1 1/16" or 1.1875".
Click to expand...
Glenn
Click to expand...

Glenn, before someone makes a big hairy deal of it, you (accidentally, I'm sure) state that 1.187 is 1 1/16................it is actually 1 3/16.

-Dave-:)
 
In case any one cares

The industrial world is going metric.

As an engineer for 15 years, I have seen a transition from 10% SI to 90% SI. The world is standardizing. And the standard is the metric system.

The US, if it plans on competing in the industrial future, will also go to SI units.

Gunsmiths are one of the few industries not converted to SI, because of the market. But give it some time, Americans will be buying rifles from China soon enough.

:(:(:(:(


I know I'm picking a fight here, and I see all your view points, but why is the world going to metric?

Because the metric system is better and easier to learn.

Why is it better?

Because you were born with 10 fingers.

Think this through to conclusion and you'll agree, if you do not, your not thinking.

10mm = 1 cm 100 cm=1m 1 cm2=1ml 1ml of water weighs 1gram. 1metric ton=1 cubic meter in volume. the list goes on......
 
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There was machinist named Peter
Who wouldn't accept the new meter
So he gladly retired
And now he's inspired
To drink beer by the pint, not the liter
 
gunmaker said:
There was machinist named Peter
Who wouldn't accept the new meter
So he gladly retired
And now he's inspired
To drink beer by the pint, not the liter
Click to expand...


That is really funny!

But.......

Please be careful where you apply the title "Machinist"....................1 out of every 1,000 who can run a machine is a Machinist.

-Dave-:)
 
bglen and Dave

BOY oh boy, you two should first decided which one is which. To me 1.187" is not 1.185" and maybe not to you two, but to everybody else there is a big difference between 1 1/16" and 1 3/16". Why not to complicate the simple metric? Let's use an imperial and we all can get confused. When you two w'll finally decide which one is the right answer please let us all to know. I only wish it was a metric...now maybe you wish too. Just please do not end up as a one of the 999

Shoot well
Peter
 
Peter,

I don't know why you are so hung up on fractions of an inch. They are not really used by toolmakers and machinists, fractions are used by carpenters and sheetmetal workers. Toolmakers and machinists use more sophisticated tools, whether working in inch or metric. These tools typically measure to 100-500 microns but they are not referred to as microns. The phrases are "ten thousandths of an inch" or "hundreths of a milli".
Ya gotta be comfortable in both worlds if you wish to move around in manufacturing today. A 6mm barrel is easier to order @ 30" in length, rather than 762 mm or 76.2 centimeters.
We all have opinions,

Jay
 
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