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Difference between the fine and coarse thread...?

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Screw Pitch Gages | MSCDirect.com
 
First the guys are right. There is plenty of information out on the web don't be lazy you may even learn additional things that will help you down the road. Here is a quick dirty way if you are not sure about measuring the pitch yourself and lack pitch profile gages. First Mic. The outside diameter to determine the size then match the pitch from a tap to your work piece. The tap will not have to match the outside diameter as you are just using the pitch profile to match you part.

Good luck
 
Perhaps measure it as best you can to know the approximate size in imperial and metric. Then take it to a hardware store and try all the nuts near that size until you find the one that fits. The higher grade nut will be a better gauge.

With having a computer one can copy a thread chart and then with a scale (ruler) can get a close idea.. but some metric threads are very close to imperial so it can be difficult to tell with jut a scale measure.

Micrometer size may be .005 or so less than the expected size but that along with the thread gauge will very often tell for most. Measure, thread gauge and try a nut..

Some oddball threads like sewing machine screws are so very uncommon that finding a nut will be difficult so a sewing machine shop may be the solution .
 
OK, all of you metriphils, here's a test.
You say there is less chance of error in the metric system.
Do you see anything wrong in this photo:

dscn0014.jpg
 
OK, all of you metriphils, here's a test.
You say there is less chance of error in the metric system.
Do you see anything wrong in this photo:

dscn0014.jpg

The kg/cm² scale is overstated by a factor of 100, relative to the psi scale.

That doesn't make the metric system responsible for the error any more than red lights are responsible traffic accidents.

PS: Not being a "metriphile", maybe I shouldn't have responded?
 
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OK, all of you metriphils, here's a test.
You say there is less chance of error in the metric system.
Do you see anything wrong in this photo:

dscn0014.jpg


If you are referring to the missing first graduation, that is fairly common. I believe it is due to the amount of pressure needed to overcome the mechanical resistance in the gauge itself. Nearly all of the gauges I have are missing the first graduation on both scales. Even the speedo in my BMW doesn't go all the way to zero.
 
Well, I wondered what had happened to my post with the picture of the gauge. I wanted to put it on the thread about what will it take to make the USA metric? Now I find it here. :crazy:

Anyway, to answer the question: There is no such unit defined as a Kilogram per square centimeter. A unit of mass per a unit of area has no meaning.

A proper metric pressure gauge would be more like this:
Psidial.jpg
 
This sounds like two complaints in one: what the hell is a square inch, then? :crazy:

A pound is a unit of force, so pounds per square inch is force per unit of area.

A kilogram is a unit of mass. In the metric system, the unit of force is the Newton. A Newton per a square meter would be force per unit of area, and a Newton per square meter is a Pascal. The proper unit of pressure in the metric system is a Pascal.

Pascal (unit) - Wikipedia, the free encyclopedia
 
Except that a pound is also a unit of mass, and the use may be unclear. So while in the metric system a kg/cm^2 doesn't make sense, the potential for confusion in imperial is high as well. Pick your poison, I guess.
 
Except that a pound is also a unit of mass, and the use may be unclear. So while in the metric system a kg/cm^2 doesn't make sense, the potential for confusion in imperial is high as well. Pick your poison, I guess.

No confusion because a pound unit of mass on earth weighs a pound of force.

Pounds per square inch is correct usage of the terms. Kilograms per square centimeter is totally wrong.
 








 
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