Ruler measured in 12ths of an inch, I saw a post about this in the metric vs imperial

[cody michael]

I have one, purchased from a garage sale this summer, I didn't even realize it until I was trying to use it a few weeks ago, really through me for a loop. one side has 8ths the other 12ths

[george wilson]

Isn't that really a square?

The carpewnter's rafter square can do so many things that a book was written about the multitude of things possible with it. I have that old book around here somewhere.

The graduations might seem strange to you,but they enable roof pitches to be set,staircase work to be figured out,divisions of circles to be figured,and many other things that the modern carpenter may not even know about. And,neither do I,not being a carpenter. But,I'm aware of the possible unique uses that the framing square can be put to. You might be able to Google around and come up with an answer to your 12 divisions'use.

By the way,most framing squares are chomped out in a big press. The GOOD ones have ground edges,not chomped out edges. If you ever find a ground edge framing square,do buy it. They were expensive squares and superior to the chomped out ones in accuracy.

[Prashun Patel]

Learned a lot from that short post, George. Thanks! (Naive question alert): What does a 'ground edge' look like?

[Daniel Rode]

The carpewnter's rafter square can do so many things that a book was written about the multitude of things possible with it. I have that old book around here somewhere.

If you find it, I'd love to know the title. The carpenter's square is an amazing tool but I know only a fraction it's abilities.

[Mel Fulks]

I think there is more than one. I have The Steel Square by H.H. Siegele ,copyright 1957.

[michael langman]

Prashun, A ground edge would look similar to a piece of metal that you sanded on a belt sander.

A large square ground on a large surface grinder is a tricky operation. A die set set up to stamp out framing squares is made to very exacting tolerances. The edges of the square have what is called BREAK in die makers terms. The edge along the perpendicular of the length of the square has a surface that is flat for approximately 1/3 of the thickness of the square. The metal here has been sheared. Then the metal under pressure gives and BREAKS, leaving a slightly ragged edge.
The tighter the tolerances in the die set the less break that occurs.

[Dave Parkis]

Audel put out a 4 volume set of books on carpentry and one of the volumes has a huge amount of information about what a framing square can do and how to use it. It really is amazing. You could probably get the set from your local library and decide from that whether its worth buying the book.

[cody michael]

Isn't that really a square?

The carpewnter's rafter square can do so many things that a book was written about the multitude of things possible with it. I have that old book around here somewhere.

The graduations might seem strange to you,but they enable roof pitches to be set,staircase work to be figured out,divisions of circles to be figured,and many other things that the modern carpenter may not even know about. And,neither do I,not being a carpenter. But,I'm aware of the possible unique uses that the framing square can be put to. You might be able to Google around and come up with an answer to your 12 divisions'use.

By the way,most framing squares are chomped out in a big press. The GOOD ones have ground edges,not chomped out edges. If you ever find a ground edge framing square,do buy it. They were expensive squares and superior to the chomped out ones in accuracy.

Yes it is a square, thanks for the info, I thought it was very interesting.

[Jim Koepke]

Audel put out a 4 volume set of books on carpentry

Audel's Carpenters and Builders Guide, I bought a set and two of the volumes are still hiding somewhere after our move from California.

In my opinion, just what I learned about the proper way to hammer nails was worth the price. Shortly after purchasing the set one of my projects involved driving a few hundred 16d nails. Normally I would have bent a few dozen. After reading the book, only one bent after hitting a knot.

I have considered purchasing another set.

jtk

[lowell holmes]

http://www.carpentry-pro-framer.com/framing-square.html

Check this site as well.

[Tom Vanzant]

Another scale, just to muddy the water....
Years ago, we had an engineer who was beyond arrogant. He had designed a panel to fill an existing void but was told he needed to recheck his dimensions or it wouldn't fit. When he got to the shop with drawing in hand, he was given a rule to check with...a foundry shrink rule. I thought the poor man was going to have a stroke before he figured out he'd been "punked."

[Jim Koepke]

Another scale, just to muddy the water....

If my memory is working it was the Dutch who until recently used an inch that was just a little bigger than the 'English' inch.

It isn't a big item on my want to find list, but it would be fun to find one of those longer rulers out on a rust hunt some day.

jtk

[Jim Ritter]

I think the title George is remembering is "Practical Uses of the Steel Square" by Fred T. Hodgson. It's a two volume set and I'm half way through volume one. It can be found as a free download on line and I have it downloaded, but for some reason some of the text and a fair amount of the drawings have been erased. So when when I saw a set come up this summer I bought it. It's interesting but dated for 1903 as the first copyright.
jim

[Mel Fulks]

Funny, Tom I dare say a lot of people don't even know what they are. Ive wondered why those small marks ,cryptic to many on the shrink rule ends havnt caused problems. At last we have confirmation.

[Mel Fulks]

It was in the "D"s... But I think it was Denmark. I once bought a nice ivory three piece 3 inch folding rule. It was long sold ,with a friendly warning ,before I happened across your interesting inch info