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Not a straight edge - a cautionary tale.

A

Andy Kev.

Nordic Pine
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I'm currently working on a book case which will be 5 ft tall. My longest straight edge is 4 ft, so I bought a very long (about 7 ft) spirit level at the local DIY place:

Long Level.jpg

I assumed that being made of aluminium, its accuracy would be good enough over a length of 5 ft. However, I discovered yesterday that at one end the base curves up a bit, making it look like the piece of wood has a downward bow. Once I realised that, there was no problem. Nonetheless, I think it worth pointing out that you can probably only trust a true straight edge to function as such. The longest I could conceivably need would be 6 ft but I might start looking for one.
 
Trusted brand names mean less and less these days but are probably a good place to start when measuring accurately is concerned
I had a headsratching half hour putting slabs down with a cheap " level" that lied ( and laughed at me) before I had the sense to test it
 
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...and I bet that even if you found them in a shop, they'd be in packaging designed to prevent you setting one against another to see if they touched all the way along. 🙁

I can remember being told that a plasterer's darby was a good compromise for someone needing a reasonable straight edge without going for engineering quality and price, but I've never needed to check that.
 
You need to be careful when buying levels, once I needed a two foot level in a hurry as one of my crew damaged theirs. In store checked 8 levels , either they were warped or if straight they didn't level the same when flipped over. Finally found a good one.
 
duke said:
You need to be careful when buying levels, once I needed a two foot level in a hurry as one of my crew damaged theirs. In store checked 8 levels , either they were warped or if straight they didn't level the same when flipped over. Finally found a good one.
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Absolutely. In the old days here in U.K., we had a species of level that was guaranteed to still function properly when dropped several stories off a scaffold (trés expensive). I carried out your test on some of them; rejected the lot. Finally found a straight Rabone Chesterman 4' that has served me to this day (45 years and counting).
 
AndyT said:
...and I bet that even if you found them in a shop, they'd be in packaging designed to prevent you setting one against another to see if they touched all the way along. 🙁
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As I recall, all of the levels, from the inexpensive store brand to the more expensive Stabila, are not packaged. However, it never occurred to me to check the level for flatness using another level.
 
Mike said:
As I recall, all of the levels, from the inexpensive store brand to the more expensive Stabila, are not packaged. However, it never occurred to me to check the level for flatness using another level.
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I withdraw my cynical remark!

The classic engineering approach to making a straight edge is to make three. If any two touch closely along the whole length, they are straight.

You need to check with three, since two could touch if they were wonky but matched.
 
30-odd years ago I found myself building toilets in the sand in Mexico, at an orphanage. Two very large burger-loving American ladies looking after 70-odd little children. I was part of a team aged from just out of school to not quite retirement. I had some skills so I was laying concrete blocks. Freshers who had only recently learned to tie their shoelaces were digging 8ft deep pits (by hand, no machinery). It was hard and very hot work, even in October/November.
I asked if they had a spirit level I could use. They had two, "But I don't know if they are true or not", said the maintenance guy. So I took them, swept a clear path on a nearby concrete base and laid the levels down. They read true. So I turned them around and they still read true.
The bloke was delighted, "You've been around a bit!". I think it was a compliment. (Edit Complement? Wash my mouth out with soap and water - I do apologise). A short while later I saw that he was showing the test to a mate of his.
I should have been nominated for a prize of some sort, really.
S
 
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AndyT said:
Was it one of these? Marples catalogue, 1938:View attachment 55860

View attachment 55861
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That's the brand Andy, though the ones I saw had metal bodies. They were vaunted as the complete canine testicles, so maybe the hardware shop I was in had bought in 'seconds' but flagged them as the real McCoy?
A lot of the builders I knew recommended them.
 
My partner saw a little wooden spirit level in a junk shop. All nicely polished wood and the brass ends polished, too. Of course, she bought it, thinking I would love it. It was, indeed, a lovely-looking tool, but she had wasted her money. It was so out of true it made orange politicians look honest and there was, as far as I could tell, no way of adjusting it, other than dismantling it and shaving off bits of wood and brass. :(
S
 
Steve Maskery said:
My partner saw a little wooden spirit level in a junk shop. All nicely polished wood and the brass ends polished, too. Of course, she bought it, thinking I would love it. It was, indeed, a lovely-looking tool, but she had wasted her money. It was so out of true it made orange politicians look honest and there was, as far as I could tell, no way of adjusting it, other than dismantling it and shaving off bits of wood and brass. :(
S
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I think the adjustment would have been to chip away the plaster holding the bubble and then reset the bubble in fresh plaster. Not something I have ever attempted!
 
I always used the yellow Stabila type 83S cast levels and had 6 or 7 at one stage but now only a couple that are still accurate as the lads abused them. I weighed some in for scrap in the end and was always irritated that the lifetime accuracy guarantee that was in force in the USA didn't apply to the UK where it was 10 years.
 
Tellurian said:
He lost me when he started sanding and the cutting the ends off. :eek:
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Sorry about that, it was the first one I found that included removing the plaster (soaking it first).
I'm not a great fan of such total rebuilding, going way past the stage when a tool is old, but properly functional.
 
AndyT said:
Sorry about that, it was the first one I found that included removing the plaster (soaking it first).
I'm not a great fan of such total rebuilding, going way past the stage when a tool is old, but properly functional.
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To be fair, he did end up with a nice-looking usable tool. Even if the label is wrong now. 😁
 
Mike said:
As I recall, all of the levels, from the inexpensive store brand to the more expensive Stabila, are not packaged. However, it never occurred to me to check the level for flatness using another level.
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Easy way to check a level is to rotate 180 degree's and it should show the same bubble position. The Stabilla ranges with milled edges are a good level, the 86 range with rubber endcaps is great but not if you are laying bricks . If you want better precision, often to precise then look at the Stabilla digital

its.co.uk

Stabila TECH 196 DL Digital Spirit Level with Case 1220mm

Get it tomorrow: Free next-day delivery to site - Stabila TECH 196 DL Digital Spirit Level with Case 1220mm. Rated EXCELLENT on TrustPilot
its.co.uk its.co.uk

Also you may no always want level, sometimes it has to be levelled by eye because of something else out of level and you do not want to hightlight the issue.
 
Spectric said:
Easy way to check a level is to rotate 180 degree's and it should show the same bubble position.
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If the underside of the level is concave then it will still seem to be good with that test, but it won't be straight. As written above, put 3 different ones against each other in both orientations and check if there is light. If there isn't, they are good. Theoretically there still is a chance of distortion that you wouldn't notice with that test, but that chance is exceedingly small.
 
Spectric said:
..............The Stabilla ranges with milled edges are a good level, the 86 range with rubber endcaps is great but not if you are laying bricks ..............
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The 83S however are excellent. These are the two I kept and have been used extensively though I still have half a dozen other makes and a Stabilla scaffold level.
The little 600mm is probably 50 years old now. Both made in Germany.IMG_3511.JPGIMG_3510.JPGIMG_3512.JPG
 
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