Metric to american

I have a machinest calc pro which is very sophisticated that i dont remember the button sequence to figure things out.

That calculator is indeed sophisticated. I looked at the User Guide. Easy to set for entering Imperial or Metric, but converting is not so easy, it is part of the Conversion menu.

The Staples calculator and others like it would be far simpler to convert between Imperial and Metric. I may have to get one for myself. I have an HP32 calculator which does all sorts of functions, but no Imperial to Metric, other than my entering 25.4/ or 25.4*.
 
I interchange systems and don't have a preference, I just work with it.
My machine scales and leads are in inches, but the cutting tool does not have a preference, it just cuts.
You want to build something of a given size, then build it. The units of measurement are inconsequential.
Conversion factors are ratios, and ratios are proportions. We could convert to a different number base or work from log-10, either way we'd be watching some dimensional value and working towards it, cut by cut.
I am not trying to sound trite, it's just a number!

Edit: Microsoft Excel is your friend.
 
I seem to have stepped in it big time here... A calculater is nice...... if you're in a class. I prefer to have things where I can convert in my head, a pencil & paper at worst. Ya never know when the batteries will give out. And most times, I don't need an answer to 5 decimal places in imperial. I do use 5 places for a mm because the numbers are easy to remember. Point03937... Pi is 3point14159 Just the way my memory works. I take the measurement of a ...motor shaft with an imperial caliper. If it is 0.079~, it's a 2mm. If it's 0.092+, it's 3/32". In either case, it will work, just a matter of what type of coupling to use. Or what size fuel line. Or whatever I happen to be using for that install.

I have a number of project books, some from the U.S., some from England, and some for pure metrics. Some very old, some recent. The only place I have any trouble is with English fasteners (Whitworth) and pipe fittings. What's called British Standard. But that's just a matter of a different method of measuring. I don't use the English systems very often, so must brush up on them when I have a project from that area. But you've got to watch the English. They started out imperial and converted to metric only recently. Sometimes the systems get a little mixed up. As in both systems side by side. A shaft 2 inches long by 1.5mm diameter. Ya got to think, 2X1/16", more or less. Or 50mmX1.5 if you're trying to stay metric all the way. If the shaft fits into something, can the something be reamed to 1/16. Or is it just to stand off something.

Most metric micrometers read to 25mm, or just a whisker fuzz under 1.0 inch. Making an imperial leadscrew cut (true)metric threads requires a 127/120 conversion gear. If you backtrack the numbers, the 127 gear is to convert 25.4 to a solid number, one without a partial remainder. The most important factor is to get comfortable with the idea of a fuzz and if it's important. A cylinder/piston/rings of any larger size won't matter that much. A shaft, especially a small one, fitting into a bearing, will. It's one of those calls you must make for yourself based on what the book says. The book you have posted is for machine parts. Take a dovetail cross-slide. The angle is important but will be the same, imperial or metric. The width (distance between) may be metric, but a fuzz too full won't really matter because of the gib and setscrews to adjust it. If it calls for 25mm, make it an inch. That's what I was refering to for you to make the call. And the worst case: As a hobbyist, if your call isn't right, ya make it again, watching the dimensions a little closer.

I'm not trying to denigrate one system under the other here. I'm only trying to give a little insight into the process of making a conversion from one to the other. I responded to a post the other day regarding need vs want. You need a set of manual calipers and a feeler guage. Anything else is a want, or time saver. Chew on that for a while.

Bill Hudson​
 
Quote:
Bill, I believe that you meant to say divide by 25.4 to convert mm to inches. I multiply by ,3937 to convert to inche. If a rough calculation is OK, .4 works. I work with both but becuase my measurement tools are Imperial, I convert almost everything to inches

Answer:
That is for centimeters;
A millimeter is 0.03937" (40 thou)
A centimeter(10mm) is 0.3937" (400 thou)
A decimeter(100mm) is 3.937" (4 inches)
A meter(1000mm of course) is 39.37" (40 inches)

I prefer the multipliers rather than the divide process. Usually I don't consider rods, yards, feet, whatever. Unless I'm doing construction work. Most times, under 20 feet I stick with inches and fractions. To a sixteenth, as a rule. It's a matter of what fits best. When I am surveying something, I measure in feet and tenths(possibly 100ths) of a foot. I have a tape measure with 10 "inches" per foot. A lot of fun with a helper that can't read a tape that well. I have another tape with 12 inches per foot, but in tenths of an inch. Used to setup a machine where I used to work.

Bill Hudson​
 
RJ......I think you meant multiply by 0.03937 for mm to inch. Left out a zero:cool:

In general I like Metric, but I'm pretty well instrumented up for Imperial, plus some machines are cross-dialed, and some have DRO that speaks Metric. Too late in life to start buying a bunch of Metric instruments. Of course, some (the digital stuff) is bilingual.
Yes, I did:face slap: I know better! Thank you Tony & Bill for catching it. Muscle memory makes running the conversion almost automatic.
I am going to chalk it up to the late hour and the half a snifter of brandy. Anyway, that's my story and I'm sticking to it.
 
Ill keep that in mind thanks Bill. Just a question how wide does a set of metric micrometers measure? Equivalent to a 0-1?
Metric mikes are ususally 25mm travel, so same as imperial ones.

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If the engineer is thoughtful they will dual dimension each drawing in inch and millimeters like so.
This is from one of todays jobs.


Same customer and same assembly but this one is not dual dimensioned as above, this part is mostly in whole 1/16s of an inch, go figure.
Simply use a calculator to convert and write the inch numbers next to the metric numbers as I do, I do this 6 days per week 52 weeks per year.
As mentioned the international standard is 25.4
It does not get any simpler than that.
 
What is your rule for rounding up when converting the metric to inches.
 
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I have a machinest calc pro which is very sophisticated that i dont remember the button sequence to figure things out.

I have the machinistcalcpro2. On it I enter a number then inch. Then tap mm and it converts the displayed number to metric. Tap inch again and it converts back to inch. Do the reverse to convert to inch. I don't know if your version is the same. I also have a calculated industries conversioncalc plus that does this and many other conversions including torque units.

Roy
 
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