How square?

[Anonymous]

I have a Shinwa 16" x 24" carpenter's square, obtainable from Lee Valley tools in Canada for US$39.50. the angular accuracy is guaranteed to be square within plus or minus 1/17th of a degree. It is made of stainless steel 2.3 mm thick.

Rockerau

 

[johnjin]

Hi Rockerau

Yeah that gives just over half a m/m in 24 inches and for me that is acceptable for wood. Of course that is at its worst tolerance and you should expect it to be a lot better than that.

All the best

John

 

[chiba]

Just to clarify, 'itting it with an 'ammer is the "standard" way to adjust a Japanese square. All the talk of British Standards seems a bit unnecessary, given that it isn't British. If you'd like a more authoratative source, Toshio Odate details this on page 20 of his book on Japanese woodworking tools. An item that he mentions that I didn't is - as you tap with the hammer, press the square's limbs in the direction you're trying to move them; I can see that this would aid the movement of the metal.

And remember, don't just bend the square, be one with the square... :roll:

 

[johnjin]

Hi Chiba

Yes you are quite right of course.
The reason that people are a bit skeptical is that squares in this country are made of two parts not one. Therefore any knocking about tends to loosen the joint. Whereas in the case of Japanese squares they are made of a single piece of material and can easily be adjusted. If anyone has got the Dick Fine Tools Catalogue for 2002-2003 it documents this on page 84. And while we are on the subject of the Dick Catalogue I would strongly advise anyone that does not have it to get it with all due haste. It is quite easily the best quality hand tool catalogue you will have ever seen. Totally in English and very realistic prices. From the photos to the paper itself. And the delivery prices from Germany put to shame many British companies. 10 euros for any order up to 250 euros and above that delivery is free.
My God this has turned into an advert for Dick

All the best

John

 

[andrewm]

Thanks all. Now on its way back. Like the look of that Lee Valley one though. Why can't UK web site state tolerances. Would make buying online much less hit and miss.

 

[Bean]

Tolerances on squares will not mean a lot to most of us, and are rarely relevant once you own the square, due to the way we handle it, store it or heaven forbid drop it. :shock:
When buying a square it is best to reverse it to check for 'square' as, if it is square it stands the best chance of staying square. 8)
I use my own apprenticeship made Squares both Standard Engineers and Centre Square, both now over 20 years old and still square.
In days of old, Engineers Squares would also be lightly tapped to return them to Square as this would move the pins holding the blade to the stock, this as others have said is bad practice as it does indeed loosen the joint and increase inaccuracy.

The only problem I would foresee with tapping a Japanese square would be the possibility of the square going out of flat(bending) which could render the divisions marked upon it inaccurate.

Ranting ramble over

Bean

 

[chiba]

It's the nature of the beast. A Japanese square can arguably be as accurate a tool as a BS standardised one, but the flexible and idiosyncratic nature of the thing means that it's something that you have to spend some time caring for, it's only as accurate as you're prepared to make it, and you'll eventually come to know the tool's quirks. In some respects this fits in with the metal versus wooden plane debate.

Bean - Agreed on bending, but it's a bendy item anyway. Just needs some care, perhaps in flipping over the square and tapping both sides rather than just one? I doubt tapping will remove the markings, as you're only tapping the very corner of the thing.

Other issues that occurred to me are the weather effects, both on accuracy and materials. It's over 80 degrees and raining here at the moment...

 

[andrewm]

Chiba,

Thank you for that explanation. Very enlightening. It makes me think though, am I being unnecessarily picky? I have no problem with tapping it to get it square if that will get me a square that can be as square as I want it. It was the inaccuracy coupled with the bendyness that was making me think that it was not fit for purpose but you seem to be suggesting that I am approaching this the wrong way. Perhaps I should cancel the return and give it go. It's certainly a lot lighter than the traditional framing square and it's not a hugely expensive item if I do find that I can't get on with it.

Andrew