# 12" Flexible (yes) precision (no) rule



## GaryK (Jun 25, 2007)

That's the biggest problem with most all scales. I always check them out when I'm buying them.


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## Grumpy (Nov 9, 2007)

Go metric Jocks, only way through to the future.


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## daltxguy (Sep 7, 2007)

Darn, I didn't have the luxury of checking it out before I purchased it. I trusted the product based on my previous experience with the 6" rule and that it was made in the USA! In any case, It's generally good advice never to rely on the end of the ruler anyway. I usually always measure from a known mark in the middle of the rule but in certain cases that's not possible.


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## GaryK (Jun 25, 2007)

Same here Steve. If I'm working with a ruler I done trust I always start that the 1" mark.


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## Karson (May 9, 2006)

Great Review. And a warning when buying a new ruler check it out.

I've heard it said that when measuring and with cutting always use the same ruler so you are using the same measurements even though it may not be a correct number.

When I buy a tape measure I but about 6 of them and check them out to make sure that they are the same. So one is where I measure the requirements and the other one is at the saw. Of course usually they both end up at the same place so thats why you need 6 so that there is always one around, that is agreement with the one on the other end.

Also check the inside and outside measurements so that the hook doesn't get you in trouble.


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## boboswin (May 23, 2007)

What do you suggest for checking it out?
I'm getting paranoid bout bogus markings!! Arrrgh! Who is right?

Bob


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## daltxguy (Sep 7, 2007)

Since the topic has come up, here's my summary of what I know could be done to ensure accuracy with inaccurate rules. I welcome any corrections or additions.

*What can you do if your measuring device is not accurate?*

Although it would be nice if all rules were accurate and consistent out of the box, this not being the case what can you do? ( In fact even if they were - many rules being metallic - things like temperature can change them anyway ) Here are a few hints on how to work around differences in measuring rules or errors found like I did with this particular rule:

1. Don't rely on measuring from the end. Start your measurement from an interior mark, such as the 1inch or 1cm mark. Remember to add 1 (or whatever offset you used ) to all of your measurements. Learn to double check your measurements. Sometimes I'll re-measure using the (unreliable) end mark just as a rough check to make sure it's what I expected and to verify that I did the math correctly.
2. Use only one measuring device for all of your measurements. Use the same rule to measure the size piece that you need and the then again when setting up the table saw or when marking the board for a cut. It doesn't really matter what the actual number is but rather than the fit is correct. 
3. If you're using more than one measuring device, check them against each other and make sure they all read the same. In most cases it doesn't really matter whether your measuring devices are spot on with the reference standard, but rather that your measurements are consistent. This way, it doesn't matter which device you pick and use, you'll get consistent results.
4. Avoid the use of rules if you can. How can you do this? Use a measuring stick Transfer your measurements onto a scrap piece of straight and flat wood or metal extrusion or bar. Use this same device for setting up the cut. This has the advantage of avoiding numbers altogether, reducing the possibility of introducing error by forgetting the number or reading it incorrectly. This is a handy hint in any case when it's difficult to get a rule in the space you are measuring (either because your rule is not long enough or there is not enough physical space ) - for example measuring the inside of a drawer or cabinet.


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## GaryK (Jun 25, 2007)

Daltxguy - number 4?

No way I could ever do without my rules. I have them from 6 inches to 6 feet. I even have a centering one.

I know which ones I can trust the ZERO point on and which one's I can't.

But that's just me.


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## daltxguy (Sep 7, 2007)

Gary, absolutely!.. but maybe I should have said 'avoid using rules where it is difficult to do so with accuracy'.
I'm not suggesting to work without rules at all ( though I'm sure it's possible) but rather to use tools other than rules where it makes sense.

The perfect example of some applications are from our very own ( if I may call him that ) Niki and his measuring stick 'jig' - there is some more discussion there about the use of measuring sticks. Lee valley calls them bar guages but then, you know, it seems like those Canadians have a different word for everything  Mr. Lee says "Any time you can transfer a dimension directly, without converting it into numbers, you avoid a primary source of error."


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## sIKE (Feb 14, 2008)

I think that the Bob measuring system are better than both the imperial and the metric measuring systems…


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