porker
Established Member
N&B do a Festool folding rule for less than £3.50
Tape Measures, just stick to one
- Thread starter garethharvey
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MikeG.
Established Member
porker":3rm8pr5s said:
Yebbut.........in inches.
porker
Established Member
MikeG.":3j7frj3h said:
Nope. In metric
http://www.powertool-supplies.co.uk/festool-folding-rule-adga-festool.html
MikeG.
Established Member
Oh thanks. That looks excellent.
rafezetter
Troll Hunter
A lot of you have posted about how you buy the "most accurate" tape measure.... accurate against what?
I have 3 tape measures, and I've never bothered to check them against each other because I use one simple rule.... for each job I just use THE SAME tape measure. It's a relative measurement after all. For some work I don't even use a measure at all but a story stick.
If you work with others I guess the only option is to make sure you all use the same brand - and compare them.
I have 3 tape measures, and I've never bothered to check them against each other because I use one simple rule.... for each job I just use THE SAME tape measure. It's a relative measurement after all. For some work I don't even use a measure at all but a story stick.
If you work with others I guess the only option is to make sure you all use the same brand - and compare them.
thetyreman
Established Member
I use a class 1 advent tape measure, it seems accurate, I got it from amazon I think, can't even remember.
rafezetter":1fmsduv9 said:
Using just one tape measure is a very good practice. Using a story stick is just as good and maybe less prone to reading error. It's easy to compare tapes if you work with others.
In answer to your question, you don't need to specify "accurate against what", as the only meaning of accuracy is absolute. A ruler is compared against the definition of a metre, which is "the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second." Since this is a tad inconvenient to do in the workshop, the practical method is to compare it with a standard, which is itself calibrated against a standard and so on back to one of the few National Labs (NPL, NIST, PTB etc) that is equipped to make a measurement against the velocity of light. The system must be "traceable", i..e. at every step the tolerance of the comparison must be specified and these tolerances summed to give the tolerance of the final measurement. And in manufacturing industry you must repeat the measurements every year on all your measuring equipment to be able to call yourself ISO9000 certified. And this is not just bureaucracy or academic fussiness. A firm I was associated with supplied some parts to a customer who alleged that they were out of tolerance according to their incoming measurements. The response was "our instruments have a certified accuracy, do yours?" They didn't!
The Tape Store publishes a table of the tolerances that are guaranteed in tapes of various lengths:
https://www.thetapestore.co.uk/tapes-ru ... e-measures
In my shop I have a 600 mm vertical vernier gauge that was calibrated when I bought it in a sale from a closing-down aircraft company, and which I have checked against calibrated slip gauges. I use it occasionally to check tape and other measures. The three Class 1 Advent tapes that I use are within spec, though you can still see the differences between them and the calibrated scale. It is the printing process that causes the error. Engraved steel rules are usually the best, even if not classified. A bargain-price new 600 mm vernier from Silverline was so far out that I couldn't use it.
Just in case anyone thinks this is too anal, I do have a need for absolute measurements, since I measure woodwind musical instruments to calculate their resonant frequencies. An error of 0.5 mm/m is significant (meaning that a musician can hear the difference in pitch). Hence the reason for getting class 1 tapes and checking them against a calibrated standard.
I guess only Bugbear and I are really interested in this stuff!
Keith
MikeG.
Established Member
MusicMan":2jar4pg6 said:
Why would you guess that?
I was in a local second hand tool store when I overheard a conversation between two elderly men who had worked at Holmans, now defunct but for a couple of centuries manufacturers of huge mining equipment. One was telling how he'd been part of the team that a building before it closed, and they'd found the biggest micrometer he'd ever seen. 108" :shock: ... yup, you read it right. It was used for their biggest cylinder bore.
John Brown
Freeloading Social media influenza
So how do you cope if you want to buy a piece of glass, cut to size, to replace a window pane, say?
Should you take our own tape measure along to the shop?
Should you take our own tape measure along to the shop?
If you use a certified (class I) tape measure and just provided a measurement, you'd have a claim against them if it was not within tolerance (and you understand the tolerances). If not, yes take your tape measure or a story stick (which is usually the most accurate).
Kudos to the original poster. I never thought to make this check. So long as you use the one tape for any given job you will be fairly safe but it's a good tolerance issue to be aware of.
So prompted by this I grabbed 3 different model tapes by my favorite brand and ran them out as far as I could in the room. All three were within 1mm of each other at 3m 30. The two bought overseas are marked as compliant with the korean and japanese standards (KSA and JIS). The one marketed in the UK is marked class 2 and CE.
For short measures I do like to use a combination square or a slide stop on a 1m steel rule. Just slide and set the fence. Using these like a story stick you never have to read them at all, no reading errors, no parallax problems or poor eyesight in bad light.
So prompted by this I grabbed 3 different model tapes by my favorite brand and ran them out as far as I could in the room. All three were within 1mm of each other at 3m 30. The two bought overseas are marked as compliant with the korean and japanese standards (KSA and JIS). The one marketed in the UK is marked class 2 and CE.
For short measures I do like to use a combination square or a slide stop on a 1m steel rule. Just slide and set the fence. Using these like a story stick you never have to read them at all, no reading errors, no parallax problems or poor eyesight in bad light.
Turbo
Established Member
One christmas my girlfriend offered to buy me a new tape measure as she knew I wanted one. After looking around I opted for a Bahco MTS825E, costing over £30!
It's something I've regretted since as it's heavy, the auto lock is a fiddle & the magnetic end picks up all the metallic filings it can find meaning you have to clean it every time you use it. :x
But the worst thing is the accuracy - it measures 1.5mm out over just a meter! :evil:
It's something I've regretted since as it's heavy, the auto lock is a fiddle & the magnetic end picks up all the metallic filings it can find meaning you have to clean it every time you use it. :x
But the worst thing is the accuracy - it measures 1.5mm out over just a meter! :evil:
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