Tape measure accuracy

[8squared]

Just how accurate are they?

Any tape measure I've bought has always had the metal piece at the start just a little loose... my current one has an 1/8" of movement.

While at screwfix today I noticed a forge steel one for £5 with a plastic end piece... a quick play revealed a shocking amount of movement.

So are all tape measures like this and no one's questioned accuracy?

 

[ajmacleod]

As I understand it, that movement should be the same as the thickness of the end hook, to provide the correct reading when taking internal measurements.

Edit... decent picture / explanation here; http://www.fine-tools.com/G303661.htm

 

[RogerP]

This is the relevant paragraph...

Attention: it is often suggested that the sliding stop at the end of a tape measure is a fault, and the tape should be returned, or the rivets tightened up by hitting them with a hammer, so that the stop is fixed tightly in place. This is a REALLY BAD idea. The stop is allowed to slide to account for the width of the metal so that one can measure both inside and outside dimensions, as with a picture frame, for example.

 

[No skills]

I've got a couple of the bigger forge steel tapes at work and they are just as bad on the hook as the smaller ones. Any tape measure should be more of an indication of size rather than a dead on measurement. As long as you remember what numbers you saw when you measured and copy it on to the workpiece it doesnt matter. IMO of course.

 

[deema]

Accuracy and use ability for me are two different things. I use the same measure to take a reference and then mark out, that way it's always spot on. I also ensure that I use the same side of the metal tang to act as the reference , the sliding tang should move an amount equal to its thickness as pointed out, however if I can eliminate sources of error I do. A cheap tape is then as good as an expensive one....they both seem to break / get lost with the same frequency!

 

[RogerP]

I've got a couple of the bigger forge steel tapes at work and they are just as bad on the hook as the smaller ones. ........

How are they bad, don't they move correctly to compensate for inside/outside measuring or what? I have a couple of good tapes and they are fine and quite accurate enough for most woodworking.

 

[No skills]

The large amount of movement in the hook compared to other brands. Even if there accurate it's really annoying, especially if the hook sticks on one measurement and releases on the next...

 

[stanley2]

As I understand it, that movement should be the same as the thickness of the end hook, to provide the correct reading when taking internal measurements.[/url]

well you learn something new all the time

 

[Random Orbital Bob]

Uh oh...for sale board jockey alert!!!

 

[Phil Pascoe]

As I understand it, that movement should be the same as the thickness of the end hook, to provide the correct reading when taking internal measurements.[/url]

well you learn something new all the time

In case you didn't know, the marks every 16" give centres for studwork, and those at about every 19 1/4" divide 8' into five.
(These are not on all tapes).

 

[stanley2]

I hope this is not meant for me as I can assure you I have no intentions of selling anything on this or any other forum. There are correct places for selling things and a forum is not one of them. as for buying from a forum how unsafe can that be. Also this is going off topic.

 

[themackay]

I never rely on measuring from end of tape if I require accuracy

 

[nanscombe]

As long as the hook is in the same position, fully open or fully closed, and you use the same mark on the tape to transfer the measurement then the distance between the two (although the measurement might be incorrect) would stil be the same anyway.

 

[Random Orbital Bob]

I hope this is not meant for me as I can assure you I have no intentions of selling anything on this or any other forum. There are correct places for selling things and a forum is not one of them. as for buying from a forum how unsafe can that be. Also this is going off topic.

Methinks yon Cassius doth protest too much!

 

[DiscoStu]

Just to agree with what others have said. The hook is meant to move by the thickness of the hook. This is so that when you push the hook (say floor to ceiling measure then it compensates for the thickness of the hook. When you pull the hook it has enough moment the other way. I'd suggest the forge steel ones with a plastic hook and lots of movement have thicker hooks and therefore more movement to compensate for the thickness.

 

[mseries]

How many of use really know when we measure 10mm we really do measure 10mm ? One of my rulers says something about it's accuracy at certain temperatures I believe, but the tapes don't, and so long as it's not too cold for me I use them anyway. To be honest I haven't even checked to see if all measurers that I use believe 10mm is the same distance.

 

[blackrodd]

As I understand it, that movement should be the same as the thickness of the end hook, to provide the correct reading when taking internal measurements.[/url]

well you learn something new all the time

In case you didn't know, the marks every 16" give centres for studwork, and those at about every 19 1/4" divide 8' into five.
(These are not on all tapes).

The More robust tapes are marked, as you say for various stud centres, for setting out.
These usually have wider (20mm) blade, and are 8metres or more long and marked at every 300mm, 400mm, 450mm, and 600mm spacings along the length.
Not seen any at 19 1/4" or 489mm.
Regards Rodders

 

[Phil Pascoe]

Keep your eyes open - it isn't necessarily good or expensive tapes that have them.

 

[blackrodd]

As you say, mseries how well do our tape measures compare?
The old four fold rule involved an awful lot of pencil lines and I would say a lot more inaccuracies, possibly another reason for the full scale "skid"to be used for size as well as detail.
I would guess and say unless you were an engineer, the average tapes are fairly consistant in markings.
Would it be a disaster if one of these exquisite pieces that members display, were to be, say, 1.223mm short of 48"?
Regards Rodders

 

[doorframe]

I never rely on measuring from end of tape if I require accuracy

Yep, I generally start from the 100mm mark to avoid the inaccuracy of the slidey bit. If it comes out at 900mm (for example), I know its 800mm. Trouble is, it's in my head that I've got to take 100mm off, so end up cutting a piece at 700mm. Done that so many times. :roll: