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

[Roger Nair]

The twelth scales on the back side of the framing square enabled carpenters to cut rafters reliably using field measurements of overall rise and run. Lets say the run is 13'5" and rise is 8'7", without calculation or knowledge of rafter length, the carpenter could set gauges on the square to 13 5/12" and 8 7/12" and step off the rafter in twelve steps. Bingo, done!! All kinds of scaling problems of a foot to inch are handled by inch to twelth.

[lowell holmes]

Sometimes a carpenter's square is out of square a bit. You can open a square a bit by putting a center punch at the haunch inside, and vice versa by placing the pinch near the outside corner.
They really are neat tools. Of course, you strike the center punch with a hammer.

Another neat use is in locating a pipe's center line, put the crotch of the square on the o.d. of the pipe and the center of the pipe will be where the blade touches the pipe.

[steven c newman]

The ruler I picked up awhile back, a Starrett No.0601

Of the four scales on the 12" long, tempered steel ruler:
One is in 12, with a section in 24, and the final section in 48
One is in(on the same side)10, then a short section of 20, then 50, then 100
Flip the ruler over
One is in 14, then goes to 28 for the last "inch"
Finally, there is a scale in16ths, then a section in 32nds, then the final section in 64ths.

makes one pay attention to what scale they were using.
Might have been to make scale drawing??

As for a "book", somewhere in the house is a blue book by Swanson.....used it quite a bit when I was doing stick framing...

[John Gornall]

I had an old rule graduated 12 lines per inch and found out it was a printers rule for laying out text at 12 letters per inch.

[James Pallas]

I try to look at any graduated measuring device as a means of portability. If you use a ruler or tape or such it is a help to move a measurement from one place to another. If are are marking the length of table legs for instance, mark one leg with a tape then mark the rest fro the first. If you use a tape for all four you have three chances to make an error. No matter what you use to measure inches centimeters a stick it is just portability. The first chance you get to introduce a fixture of some source use it. Marking gauge, combo square, set up block, chisel width or such. Just my opinion of course. I think you will find lots of patterns hanging on the walls of old shops, less chance of errors.
jim

[Jim Koepke]

For some reason this morning the normal reply window isn't working. So instead of copy and quoting my reply is with quote and cut up.


If you use a ruler or tape or such it is a help to move a measurement from one place to another.

About 40 years ago I worked in a silkscreen printing shop. I noticed one of the shop made rulers didn't fully agree with another ruler. They laughed and told me about a slight problem they had many years earlier. Something didn't measure exactly to a customers specification. It really wasn't critical the person was just being difficult.

The owner and the manager took out their tape measures and put them against the standard rule I was using. At certain points they didn't agree. I think the technology of making tape measures and rulers has improved, but most of the time, being a 32nd of an inch off over 10 feet isn't going to be a deal killer.


I think you will find lots of patterns hanging on the walls of old shops, less chance of errors.
jim

Besides, why redraw something every time you want to make another?

I even make patterns for circles so I don't have to break out a compass every time. Besides, having a pattern makes it faster to put a radius on a corner than using a compass.

jtk