measuring the length of a screw

does screw length include the part of the screw that is in the nut?
I need a tool to measure the length of a screw. I would normally say,
use a ruler. But my local DIY stores don't sell them, and the rulers
that stationary shops sell are no good because the 0 is not in line
with the end of it. I don't really want to get one of theirs and file
it down.
A micrometer would measure screw length including the nut, but not
excluding it.
How should i measure it, what product should i use and who sells it?!
Reply to
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I was tempted to think your post is a troll, but then I realized that SWMBO might just ask the same kind of questions, bless her heart, so:
No, screw length does not include the nut. It is the length of the screw measured from the underside of the screw head to the end of the screw.
To make an accurate measurement,
Find someplace and buy a steel scale, like this one for example:
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Which, if you have a good eye, will let you measure the screw length to 1/64" easily.
Or, if you want to "automate" your measuring, get one of these:
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Or go hi-tech and get one of these:
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(One similar that is fast becoming the most reached for tool in my shop...Particulary as my eyes age...
By the way, and just to be my PIA pedagog self, strictly speaking, a "ruler" doesn't have any markings on it, it's a straight piece used for drawing straight lines. (Like the ones on "ruled paper".)
The thingy with the markings and numbers on it is properly referred to as a "scale".
Reply to
Jeff Wisnia
Except in the case of a countersunk screw where the length includes the head, ie for countersunk screws the screw length is the overall length.
Jeff Wisnia wrote:
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Reply to
David Billington
a straight piece used for drawing straight lines.
I've been taught that this is a "straightedge"....
...and this is a "rule"...
a "scale".
...and this is a "miscalibrated rule" to allow for shrinkage in molded parts.
Reply to
Randy Replogle
Me too...I should have pointed out the example I gave was for the original meaning of "ruler" which has changed over the years. I certainly agree that if you say "ruler" most people will immediately have an image of the ubiquitous one foot long wooden dime store thing the OP mentioned.
But, most chipmakers will tell you they have a "six inch scale" in their shirt pocket, not a "six inch ruler".
Maybe that's because you can't tighten a slot screw very well with the end of a wooden ruler, can you?
Reply to
Jeff Wisnia
In my apprenticeship theory class, the "scale" is the little black etched, stamped or painted lines with the numbers which are on the "rule".
Interesting note, my instructor used to work for Rolls Royce and they used to have their 6" rules calibrated once a year (or more, I forget the exact cycle)...
Reply to
Robin S.
Ah HaH, now I understand! That's why those Rolls Royces cost so much! Steve
Reply to
Steve Lusardi
In a related subject:
When the depth of a drilled hole is called out it usually doesn't mean the depth of the drill's point at the hole's bottom. Depth is measured from the place on drill's end where the cone point begins. For example: A hole made with a118 deg. drill (59 deg. angle from side to point) would need to be drilled a little deeper in order to make the hole's full diameter reach down to the specified depth. In other words, it is necessary to drill deeper by an amount equal to the pointed portion of the drill. The math would be: Extra depth = sin 59 x (1/2 diameter)
And it goes without saying (although someone will surely do it): For critical depths requiring full diameters at bottom (drilled, then reamed "square") the extra amount would be subtracted from the specified depth of hole.
Bob Swinney
Reply to
Robert Swinney
Get the ruler from the Stationary shop. Hold it beside the screw. Read the length. Accept as fact, that screws come in a limited selection of lenths, most often in quarter inch or five millimeter increments, a range easilly estimated from a ruler's scale held near the screw.
If you need to know more accurately than that, what the length is, remove it and place it upon the aforementioned ruler.
On screws in general, the length is from the flat surface, to the end. That is to say, from the underside of the head, if it has a domed lump on the fat end, or from the flat end surface, if it is meant to mount flush with a cone shaped head.
Cheers Trevor Jones
Reply to
Trevor Jones

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