How exact are measurements/conversions?

[thevillagetuba]

I am wanting to take on a project to modify a horn for which I will need 19mm tubing. I can easily acquire some tubing that measures .743" and .745" (though I believe 19mm comes out to .748"). Are measurements of tubing pretty accurate or are these .003-5" differences plausible to use in place of 19mm? I know that some of my sockets and wrenches work interchangeably between .75" and 19mm but not sure if that .002ish" difference, depending on the chart, would correlate to the difference in tubing size also working.

Thanks.

[Dan Schultz]

I normally don't let a couple of .001" be of much concern unless it's a case where inner and outer slide tubes are involved. The actual measurements might bounce around a bit due to manufacturing tolerances.

[skyguy]

0.001 inch = 0.254 mm

That is a small difference for a material that is relatively malleable.

.04 inch = 1.016 mm

I'd call that a maximum tolerance for tubing materials, with .03" and below being ideal. A few thousands of an inch is nothing to worry about.

Check your diameters for out-of-roundness as well.

Keep in mind the precision of your measurement tools and of course human error.

NOTE: I have zero instrument repair experience.

Edited because beer and math do not compliment each other!

[UDELBR]

When you see the mismatches and bad tolerances built in by well-known factories, you'll know the margin you mention ain't a big deal. My Hirsbrunner was a nightmare as far as that's concerned. But it was shiny.

[Dan Schultz]

0.001 inch = 0.254 mm

That is a small difference for a material that is relatively malleable.

.004 inch = 1.016 mm

I'd call that a maximum tolerance for tubing materials, with .003" and below being ideal.

Check your diameters for out-of-roundness as well.

Keep in mind the precision of your measurement tools and of course human error.

NOTE: I have zero instrument repair experience.

Check your conversions. There are 25.4 millimeters to an inch. 1mm = .03937" - .001" = 0.0254mm - .004" = .1016mm

[skyguy]

Whoops! Thanks Dan. Those decimal points make a huge difference.

I'm really smart. I swear!