In article , wrote:
On Thu, 21 Aug 2003 14:34:27 GMT, Doug Miller wrote:
The best suggestion I have for checking the squareness of a square is to
compare it against a square of known accuracy, one which is certified by its
manufacturer to be accurate to so many thousandths of an inch per whatever
length. Or simply buy such a square in the first place. Starrett makes an
excellent 12" combination square, which can be had for about US$60 if you
shop
around some.

Couple more questions:


1) how are the Incra Guaranteed squares as a 'reference' square? Any
others of similar design i.e. reference square that would be worth
investigating?

I haven't used those, but if they're as accurate as Incra's table saw miter
gauges, they ought to be pretty darn good.

2) I've heard a bit o' rumbling here and there about the combo square
not being the best choice for a 'trusted' square due mainly to the
moving parts. Any comments in that department?

Undoubtedly true, but when looking at precision tools, you're comparing
differences of only a couple thousandths per foot anyway. For me, being able
to buy *one* tool that gives precise 45 and 90 degree angles *and* linear
measurement accurate to 1/64" is more important than a difference of two or
three thousandths per foot.

I've been eyeballing some Starrett equipment to go along w/ some
Mitutuoyo that I have for some other uses (digital calipers and
micrometers). Suggestions on places for the best prices?

Can't help you much there. Rockler has decent pricing, not the best, not the
worst. Other than that, I don't really know. Sorry.

--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)