Square squares

[PeterC]

I once developed an infallible method of getting it right. Scenario: old cottage, fit venetian blinds. Ceiling not flat/level/horizontal, ditto top of alcove, ditto sill, ditto floor. Radiator hadn't joined the party - straight, horizontal top. However I 'aligned' the blind it looked wrong, with a gap somewhere that tapered, then I realised that the bottom of the blind would rarely be horizontal as such blinds usually drop crookedly.

Now for the touch of genius: asked my mate's wife to tell me when the blind looked 'right', put it up and she was happy. My mate came in and said that it was wrong - I gently explained that I had approval (she wasn't there by then) and all was well.

So now you know - SWMBO can replace all the squares, levels and edges in the world and is better even than a laser level.

[Roger Mills]

They could both be out - in an equal and opposite way - even if you can see no light.

The only way to check is with one square at a time - turning it round to see whether it's the same both ways.

[Nick]

Trueing a square is not rocket science. I havent seen and cant find the OP. This is how I was taught at school so many years ago. You need a known straight edge at least the length of the blade of the square and at least twice the width of the square stock. Manufacturers edge on plywood is normally good for this. Place square firmly to known straight edge and carefully scribe or pencil a line the full length of the blade. Flip the square stock over and scribe or pencil another line close to the first. This will show any inaccuracy in the square. File and drawfile until it is spot bollock. Angle grinder not recommended. HTH Nick.

[meow2222]

Not with squares, Silverline are perfectly good. At the end of the day its = only a bit of stamped metal, and any even vaguely modern stamping machine c= an get that right.

To correct it, hammering on the inside or outside of the corner expands tha= t area of metal, changing the corner angle. This is the proper way to do it= , don't even think about trying to file the thing down. Plastic handled one= s aren't correctable this way, and aren't worth filing, bin if out of shape= .

NT

[fred]

And the likelihood of that is what ?

[Roger Mills]

Finite!