The Framing Square Story

shinnlinger · March 12, 2010, 05:39:43 AM

I bet those guys that use to hang the tongues out of their tool boxes used to have to adjust from time to time...

thecfarm · March 12, 2010, 08:00:46 AM

A nice educational thread that I have missed over the years.I'm not a big time builder,but at least I know what all those numbers mean now.I have booked marked this so I can find it again and use what you have taught me Jim. Thank you.

bigshow · March 12, 2010, 09:31:24 AM

Jim,

I cry foul - that circle technique must be a trick from the devil. Cool!

GaryinMississippi · March 12, 2010, 01:06:24 PM

Quote from: etat on November 27, 2004, 11:30:44 PM
From the book:

Height of a tree

The height of a tree can by measured by the same way by using the steel square taking A,C,D for the square. Now we will call AB a tree, and AC the blade of square, and CD the tongue 16 inches long. We place the end of the blade against the tree with the blade level or the tongue parallel with the tree and using inches on the square for feet; now place a straight edge at end of tongue D, letting it cross the blade at E and in line with top of tree. Suppose the straight edge crosses the blade at the 6 inch mark, then there would be 18 inches from that point to the tree and the height of the tree would be A E 18 multiplied by C D 16 divided by E C 6. Thus: 18 times 16 divided by 6 equals 48 feet, which is the distance from where the blade hits the tree to top. The distance from where the blade is placed against tree to the ground must always be added to this measurement. Now, if the tree is not plumb, put the tongue parallel with the tree, and it will always work right even if the tree leans at a angle of 45 degrees.

It seems to me that if the straight edge crosses the blade at the 6 inch mark, you have 18 inches times 16 inches divided by 6 inches which will give 48 inches, not 48 feet. What is the rationale for using feet instead of inches?

Mad Professor · March 13, 2010, 09:56:17 PM

Hi Jim.

You can do all that and more with a divider/compass! Even lay out knee braces and not invoke Pythygoras

Best,

MP

routestep · March 15, 2010, 09:24:46 AM

Gary,

You know how on a piece of paper you can draw a building or shed that's fifty or one hundred feet long, but on the paper it's only inches long. Same thing with the framing square and the tree. The inches represent feet. The proportions are the same.

GaryinMississippi · March 15, 2010, 11:14:00 AM

Quote from: routestep on March 15, 2010, 09:24:46 AM
Gary,

You know how on a piece of paper you can draw a building or shed that's fifty or one hundred feet long, but on the paper it's only inches long. Same thing with the framing square and the tree. The inches represent feet. The proportions are the same.

But on paper, everything is to the same scale. 1/4" on the paper represents 1' on the building. So a line 1" long will represent 4' but the line itself will only be 1" long. In the example given, ae is 18 inches long, ec is 6 inches long and cd is 16 inches long. This will make line ab 48 inches long and this line is the tree, it doesn't represent the tree. In other words, if ae, ec, and cd are as given and the end of the framing square is against the tree, the top of line db will be 48 inches above the square, not at the top of the tree.

When doing proportions, you must use the same scale for all parts of the proportion. So, if ae, ec, and cd are in inches, then ab will be in inches.

routestep · March 16, 2010, 08:31:04 AM

I see your point.

I guess I thought he was sighting to the top of the tree along line bed. Then he would have similar triangles and a proportion. Somehow cd has to be measured though and one ends up with a real short leg ae (potential for errors in tree height)

Think I'll go with a protractor on a stick and a weighted string and trig tables while I think over using a square.

JD

Brad_bb · March 17, 2010, 12:21:51 AM

I like the Japanese made framing square from Lee Valley. It's stainless and well made, far better than anything a big box would sell. I'd consider both that I purchased as "square".

knowslittle · March 18, 2010, 01:01:24 AM

I bought a Shinwa framing square from Lee Valley, but found it was way out of square. Tried the punch and hammer trick, and although it took a lot of hard hits on the stainless, it did come back into alignment. More than a bit dissapointed though, given it's pricetag.

knowslittle · March 18, 2010, 01:14:38 AM

Regarding Etats thread, my first accountant told of an old Swedish carpenter who had only a few years of formal education, yet did the multiplication and division for his taxes using just his framing square. When my accountant called him on this, the old man took the square from his truck up the the CPA and showed him how it's done. Some 20 years later I found just how to do this in one of my old books. Kind of a cool story.

dukndog · February 21, 2011, 12:43:34 PM

Searching on squares I found this info Jim shared a few years ago. Thought it may be a good re-read for some!!
Thanks Jim for the time to put this together!!

DnD