I've noticed that a folding carpenter's rule is often included in lists
of essential basic tools. I'm not sure I understand how a folding ruler
differs from a tape measurer. Could anyone explain what the advantage
of a folding ruler is?
If you turn the rule on edge to make your mark, all parallax is eliminated.
I have a 6 footer that I cut in two pieces so that I could have a folding
yardstick (actually two folding yardsticks.) I also have two 8 foot rules,
including a plumbers rule that reads inside.
Allows you to take, or transfer, inside measurements better than a
retractable tape measure.
It will also 'stand out' almost as far as a Big Max, and it is great for
wiping the sweat off your brow, as my cabinetmaker grandfather often used
Whatever the rule you use, you'll get the best results if you use the
same one for all measurements in one project. If you use a couple of
rulers make sure you compare them. You'll probably find that they are
all off a little bit. So if you use the "long" one to measure one part
and "short" one to measure a matching part, you'll probably not be
able to fit them together.
The rule with the little brass sliding extension is better than a tape
measure for getting accurate inside measurements.
Metal tapes expand and contract with temperature at a different rate
than wood. If you want to be real accurate, a wood carpenter's rule
would expand and contract nearly the same as your wood would.
(However, I'd be the first to admit that, over the usual 6' or so,
the difference wouldn't be much to speak of.)
Over long distances, steel tapes stretch a little, too. Between temp and
tension, the difference can be 1/4" or so. Some longer tapes are made
of fiberglass, and probably are best used with a "calibrated" tension, too.
But mostly, I find that a rule with the extender eliminates the
required when doing inside measurements -- no trying to "read the curve."
As everyone has mentioned, taking inside measurements is the real
One thing I've noticed is when new, they are not always accurate to a
tape measure. If you lay your tape along the rule, sometimes you
notice that all of a sudden one section will start to run off. This
can usually be corrected by tapping on the joint of that section to
get it back in line. We always check them.
Lufkin used to make one with the sliding extension on both ends. I
think it was the x6x model but I'm not sure if they even make it
anymore. With that model it doesn't matter which end you un-fold you
always have the extender on that end.
I use both folding ruler and retractable tape in my daily work. They
are both useful.
For accuracy the folding rule is superior. Retractable tapes use a
metal end that is supposed to slide back and forth for outside measure
and inside measure. If this feature is working correctly the tape
should be more or less accurate. They are probably accurate to
1/32-1/16. If the feature is not sliding correctly measurements can be
off by 1/8 plus.
The folding rule is more accurate and as based on the users skill.
Well, you look like an interesting guy when you're using one.
Generally speaking, a rule is more accurate, but I wouldn't count on a
folding bit of wood to be signifigantly better than a tape, especially
considering the stepped nature of the extended rule- if you're doing
layout work, that thing is not going to lay flat, and it doesn't make
a good straightedge.
AFAIK, I've never seen a folding rule in a list of essential basic
tools- they've been replaced by tape measures, for the most part. For
things requiring a really accurate measurement, I usually use a metal
4' rule or one of my smaller cabinetmaker's rules, and even then I get
funny looks if I'm on a jobsite. My guess is that those old folders
were around as a good solution to fitting a long ruler in a short
toolbox until retractable tapes were widely availible, kind of like
braces- they were, and still are, just fine- but you don't see them
much anymore now that cordless drills are so common.
But! If you turn the folding rule on edge it does lay flat and as I
mentioned in an ealier post,
all parallax is gone. A tape is one of the least accurate measuring devices
in my opinion.
I use a folding rule or a cabinetmakers rule, however I use story sticks
more than either.
About the only time I will use a tape is to check diagonal dimensions, and
then I turn the tape on edge for accuracy. I don't care about funny looks
when I'm working. :-)
It can be, but doesn't have to be inaccurate. If you've got three
guys using different tapes and yelling measurements to one another,
then they can vary by up to 1/8" sometimes- but if it's one guy using
one tape, you can always run it an inch by and rock the tape so that
one edge is laying flat- then it is as accurate as a story stick or
rule, provided you don't forget to always run it an inch by. (Though
I will admit it's easy enough to measure an inch by, and then cut a
piece with the tape hooked on the end, DAMHIKT)
Nor do I, generally, but sometimes it's a matter of avoiding the boss
or foreman's irritation. Even though it's more accurate and takes no
more time to use a rule, it's amazing how many carpenters think it's a
waste of time- and assume that you are being fussy and lazy if you use
them. Of course, most of the framers I've worked with contend that a
sixteenth is a non-existant measurement- to those guys, parallax does
not exist either.
Now if you're talking about working in my home shop, I'd have to
agree- anyone caught making funny faces can get out and leave me to my
own devices! But even then, I just use the inch-by method for
anything over 4', and so far, it's always worked fine.
Tue, Aug 15, 2006, 3:27pm (EDT-3) email@example.com (Richard) doeth
<snip> Could anyone explain what the advantage of a folding ruler is?
None for me, I've managed to break every one I've owned.
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Mercy and lawyers were invented by the guilty.
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