Thread: Chappell Master Framing Square

05072012, 07:49 AM #16Veteran Contributor
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Re: Chappell Master Framing Square
I wish you also sold them through Amazon so I can get this past the wife, without raising her eyebrows!! :)
Rich

05082012, 03:43 PM #17Veteran Contributor
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Re: Chappell Master Framing Square
I picked one up at lee valley last week, I figured it would at least be an alternative to show students. My nether regions puckered when I paid over $100 for it but it's only money.... right?
I had a day off today after frantically closing out a job through the weekend and had a chance to start on the booklet and play around with it today. Dividing the inch into 20ths, 18 inch tongue, ratios of hip/run per inch for determining rafter length, no more conversions to decimal!!! I could go on and on. Just brilliant and I haven't scratched the surface.
Mr. Chappell, if you're within earshot, you made a great contribution to our craft with this product. I still have to teach rafters using a conventional rafter square but I think this square has not just a practical advantage to a carpenter in the field but will make it easier for a student to visualize roof problems in the more intuitive approach to the math and geometry you've used in producing this square.

05092012, 12:08 AM #18Veteran Contributor
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Re: Chappell Master Framing Square
Why 20ths?
Why 18" tongue? (Other than it's longer)
Why hip/run per inch? Whats the advantage?

05092012, 08:15 AM #19Veteran Contributor
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Re: Chappell Master Framing Square
Jim,
20ths are for decimal equations, (.1 divide by 2), so is the H/V per inch, decimal units, for accurate onsite calculations with a pencil on a scrap. (in case the CM croaks)
The 18" inch tongue makes the square a 3/4/5 triangle ratio. But there is so much information on this square that I suspect it was really lengthened to help get it all on there. Lol. =)
It's a very cool tool!

05092012, 08:40 AM #20New Member
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Re: Chappell Master Framing Square
Great question,
I think it helps if you don't think 20ths, think decimal. You wouldn't read as 13/20ths as you would with 16ths, you read decimal .65 and apply that number directly to square. With markings at each .05 (twentieth) you have a accuracy to a higher degree than 10ths and you also have exact makings at 1/4, 1/2, & 3/4 to use as snap guides when applying numbers (ratios from tables) to square. .25 .3 .35 .4 .45 .5 etc. so to apply a number like .363 it would be easy to mark very accurately without need to convert to 16ths. This becomes quickly evident when laying out angles with the tables. Also any ratio on the table can easily be multiplied by 10 by moving decimal and using over 10 for direct application on the square to layout angles.
Most importantly the 18" tongue allows for the Patented unequal pitched tables to run 415/12. It also allows for greater layout flexibility as you can span larger lumber with your desired angle ratio (think small v. large speed square), and why not its a 3,4,5 triangle...
Its hip length/inch of common run in decimal form so it can be applied to any run in inches to get a hip length. Its simple multiplication You could almost do the math without a calculator. Even for what some might consider a tricky roof.
Example
9/12, 12/12 bastard roof
given a 120" run for dormer roof (9/12)
hip rafter length is 1.458" per inch common run (line 3 Unequal pitched table)
120*1.458= 174.96" Quick and Easy...
The ratio for the 12/12 side is also given if you want to use that run instead 1.944
This really is only the tip of the iceberg in terms of information on the square. It is a powerful reference tool, something that is very handy to have in your tool chest.
Tait Chappell
Chappell Universal Square & Rule Co., LLC
http://chappellsquare.comLast edited by mortyten; 05092012 at 08:43 AM.

05112012, 10:39 AM #21Veteran Contributor
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Re: Chappell Master Framing Square
"Its hip length/inch of common run in decimal form so it can be applied to any run in inches to get a hip length."
What does that mean?

05112012, 03:50 PM #22Veteran Contributor
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Re: Chappell Master Framing Square
The rafter lengths / unit of run are expressed as ratios (Hyp/run) on the Chapelle Square whereas they are expressed in feet and inches on a conventional square.
That means you can use the tables on the square with any units to calculate the length of a rafter as long as you know the total run in the units you're working in. Yards ,feet, inches, mm, cubits....it's all the same.

05212012, 02:18 PM #23Veteran Contributor
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Re: Chappell Master Framing Square
sbe. you have peeked my interest more than a little
you seem to have added purlin cuts
have you got ALL the purlin cuts, for both LEVEL and INCLINED purlins
next question
your square seems looks as if it is designed to work primerily in imperial (ie inch pitches)
can it deal with "degree" pitchesLimey Carpenter

06012012, 08:53 AM #24New Member
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Re: Chappell Master Framing Square
Thank You to Lee Valley for featuring our framing squares on the back cover of the June woodworking catalog
LeeValleyCatalog.jpg
Tait Chappell
Chappell Universal Square & Rule Co., LLC
http://chappellsquare.com

06152012, 06:32 AM #25Veteran Contributor
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Re: Chappell Master Framing Square
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The defamation statement is false.
Roof Framing Geometry
http://sbebuilders.blogspot.com/
Using the Equal Pitch Rafter Table on the Chappell Master Framing Square for Stick Framing A Conventional Rafter Roof
Line 1 on the Equal Pitch Rafter Table is the common rafter length per inch of common run. In this 8:12 example, using a common rafter run of 96", we multiply 96" x 1.202 = 115.392" = common rafter length for the common rafter run of 96".
Line 2 on the Equal Pitch Rafter Table is the hip rafter length per inch of common run. In this 8:12 example, using a common rafter run of 96", we multiply 96" x 1.563 = 150.048" = hip rafter length for the common rafter run of 96".
Line 3 on the Equal Pitch Rafter Table is the tangent of P2 Jack Rafter Side Cut Angle or the length of purlins (roof sheathing). In this 8:12 example, using a 48" wide piece of plywood we multiply 48" x .8321 = 39.9408". Measure off 39.9408" along the top side of the plywood to mark the plywood roof sheathing offset cut line. To find the Jack Rafter Side Cut Angle enter 0.8321 in the CMC and press [CONV][TAN] for the Jack Rafter Side Cut Angle in degrees, 39.76384°.
Line 4 on the Equal Pitch Rafter Table is the tangent of C5 Hip Rafter Backing Angle. Using the value on line 4 we can mark off half of the hip rafter width x .4264 for the depth of the hip rafter backing plane line. Or enter 0.4264 in the CMC and press [CONV][TAN] for the Hip Rafter Saw Blade Backing Bevel Angle in degrees, 23.0934°.
Line 5 on the Equal Pitch Rafter Table is the tangent of R2 Square Tail Fascia Saw Miter Angle on the Hip or Valley Rafter. Or the purlin housing angle on a hip or valley. Enter 0.3264 in the CMC and press [CONV][TAN] for the Square Tail Fascia Saw Miter Angle on the Hip or Valley Rafter in degrees, 18.07668°.
Line 6 on the Equal Pitch Rafter Table is the tangent of R5 Hip Rafter Diamond Post Miter Angle. Or the Housing angle of the Hip or Valley to Principal Rafter. Or the Hip Rafter Mortise Layout Angle on the Ridge. Enter 0.3333 in the CMC and press [CONV][TAN] for the Hip Rafter Diamond Post Miter Angle in degrees, 18.43323°.
Line 7 on the Equal Pitch Rafter Table is the tangent of R4 Hip or Valley Rafter Side Cut Angle. Enter 0.9045 in the CMC and press [CONV][TAN] for the Hip  Valley Rafter Side Cut Angle in degrees, 42.12934°.
Line 8 on the Equal Pitch Rafter Table is the tangent of P1 Purlin/Square Hung Fascia/Frieze Block Miter Angle set perpendicular to the plane of the roof. Enter 0.5547 in the CMC and press [CONV][TAN] for the Purlin/Square Hung Fascia/Frieze Block Miter Angle in degrees, 29.01713°.
Line 9 on the Equal Pitch Rafter Table are the C5  HipValley Rafter Backing Angle in degrees and the Saw Blade Bevel Angle for C1 Purlin/Square Hung Fascia/Frieze Block Saw Blade Bevel Angle set perpendicular to the plane of the roof.
Without going to Joe Bartok's or my website where would anyone find
the Hip Rafter Diamond Post Miter Angle....line 6 on the Chappell Master Framing Square
SimLast edited by sbebuilders; 06152012 at 06:50 AM.
Elucidation of the stuff is self evident
http://www.sbebuilders.com/tools
http://www.raftertools.com/
http://www.raftertools.com/iPhone/plus/

06152012, 08:44 AM #26Veteran Contributor
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Re: Chappell Master Framing Square
Anybody who buys a tool or an expensive calculator expecting it to magically gift them knowledge and experience is going to be frustrated and disappointed. Tools are just are levers and multipliers that make our jobs easier and make us more productive.
The Chappell framing is no different, I can use a compass to mark out a line perpendicular to an edge but having an accurate square is much more convenient and efficient. Adding useful information to that square is a nifty idea but it's important for anyone buying an expensive square or calculator to understand that they are buying convenience and information NOT knowledge. It takes the hands of a knowledgable tradesman to use these tools productively.
I have a pretty good grounding in geometry and can easily solve most roof problems using a scientific calculator. (I learned to do it long hand but I find doing square roots and the like slow going these days.) What I find with roof problems is that it isn't difficult to do the math, the difficulty lies in seeing the problem. You can teach the math, you can teach the student how to use the tools but it takes experience and good spatial sense to figure out where in three dimensions the actual lines and angles you are calculating actually lie.
I disagree with relying on a fractional calculator for doing arithmetic in imperial measure until you have learned to convert fractional measurement to decimal and back again and are fully competent at it.
Having said that I have a construction master calculator on my desk, in my tool box and on my iphone however I learned to work in imperial measurement as a Quantity Surveyor where we were taught to convert feet, inches and fractions to decimal and back again using a scientific calculator. It doesn't take long for a student to discover that 10" is .83 of a foot or the 5/8" is .625 of an inch. When the student gets familiar with the math to the point that they barely have to think about it it frees up the mind to understand and visualize the geometry rather than trying to understand the math.
The same thing goes for calculating the line length of rafters using sum of the squares then deriving the ratio of the line length to run. You can get this information off a square or you can punch the appropriate buttons on your CM calculator however you don't get an understanding of the geometry. If you calculate the line length of a rafter using a $12 calculator for a couple of hundred different rafter problems then you get to the point where first you don't need a calculator to figure out that the square of 9 is 81 and the square of 12 is always going to be 144 .... and the hyp is of a 9:12 triangle is 15 .... and the ratio of LL to run is 1.25. You do it enough times that information is understood THEN you can use a CM calculator or the numbers on a Chappell square with confidence.
The Chappell framing square is calibrated in twentieth parts of an inch which is incompatible to other measuring implements such as the folding rule and tape measure which are calibrated in sixteenths and/or thirtyseconds of an inch.[/QUOTE]
I think you are looking at this the wrong way. The Chappell square is in 20ths because of it's function as a calculator not for use as a measuring instrument. It's done that way to make it easy to work in imperial measure without having to use a calculator to convert feet inches and fractions to decimal. There is a table on the square with the decimal equivalent to inches and fractions so using only the square you can convert from imperial to decimal and back again without using a calculator.
I agree 100%. Both are just tools and if you don't have a basic understanding of the geometry and math involved in roof construction, which is really relatively simple, you can never get full use out of any tool. Again tools don't provide knowledge and understanding, you have to have that in order to get the full use out of either of these tools and if you don't have the sense to know when you aren't reading the right numbers on the square or punching the right buttons on the calculator then you can just as easily be cutting firewood as cutting a roof.
I teach that you use 2 methods to come up with your pattern rafters when cutting a roof. One with a calculator and the other stepping off so you can check one against the other. I teach using a standard rafter square and a scientific calculator however it's up to the individual carpenter as to what tools they want to use once they are in the field. The Chappell square and CM calculator are both good tools as are rafter tables, speed squares and rafter square. As long as you understand what you are doing and have a check before you start cutting an entire lift of lumber whatever method gets you from point A to point Z is the right one.

06152012, 09:13 AM #27Veteran Contributor
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Re: Chappell Master Framing Square
Good stuff Dave. It sounds like we walked the same path in our roof journey. The one major difference is that I never used a scientific calc. I preferred the cheap $4.99 solar dual power that you find at the walmarts. I was picky about which ones I used though; I only bought them if they had a separate memory clear button and of course, the sq rt key.
Regarding the scales on the squares edges. I couldn't use any square that had different scales on the various edges. It drove me bonkers because I'm so anal about marking things exact and I often used the square as my measuring tool. If I needed something 12 5/8" long and I placed the square on the material, only to find out that I had to convert the 5/8" to 20th.....I would toss the square into the field!
Literally.
I will only use/buy a square that has the same markings on all sides. I don't care about the tome written on the sides. I never used any of that anyways. Some of them might be very helpful but they can be carved somewhere else too.

06152012, 06:29 PM #28Veteran Contributor
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Re: Chappell Master Framing Square
There's only one real carpenter's framing square in this picture. The Chappell Master Framing Square. It's the only one with the hip rafter backing angle imprinted on the square.
framingsquares.JPGframingsquares2.JPG
SimElucidation of the stuff is self evident
http://www.sbebuilders.com/tools
http://www.raftertools.com/
http://www.raftertools.com/iPhone/plus/

06152012, 08:33 PM #29Veteran Contributor
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Re: Chappell Master Framing Square
Been away for a while making some major changes to my life, including my longawaited move to DC..., I like this topic and wanted to weigh in...
Most everything we do in this business comes down to efficiency, at some point. As long as we're not discussing a hobby, but instead, how we make a living, it's really about getting the work done at the quality level desired, in the least amount of time, and/or for the least amount of money.
We are competing against others for the work. So I believe the pursuit should be developing methods to get that roof figured and cut in the least amount of time. So we put tools into the process that reduce the time it takes to get the job done.
Whether it's racking your rafters so you can gang cut them, or planning the layout of a hip roof so that you have the most number of jack rafters of the same length, or whatever... these things are in the interest of efficiency.
I have personally used a scientific calculator and converted answers to feet/inches, used the perfootrun info on a framing square, used the Pythagorean Theorum, a CM calculator, and more recently, a spread sheet and Sketchup, all to figure and cut roofs. And knowing what I know now of how all those tools work toward the end goal of getting the roof built, if I were teaching guys today how to do this, I would totally skip the framing square.
We have tools that weren't available when I learned how to cut roofs. And I believe some of them now eclipse the framing square, so it no longer needs to be part of the process, either of the learning, or the doing.
And even without a foundation built upon the framing square, I know I could teach roof framing techniques, and end up with guys who would have a solid understanding of the process, and really know what they're doing.
Hope everyone has lots of fun work going on right now!
Tom1) Unconsciously Incompetent: He knows not, and knows not that he knows not. He is a fool. Shun him.
2) Consciously Incompetent: He knows not, and knows that he knows not. He is simple. Teach him.
3) Unconsciously Competent: He knows, and knows not that he knows. He is asleep. Wake him.
4) Consciously Competent: He knows, and knows that he knows. He is wise. Follow him.
May we all endeavor to progress from not knowing that we know not, to knowing that we know.

06162012, 12:53 AM #30Veteran Contributor
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Re: Chappell Master Framing Square
Tom
Good post, like the signatureMark Parlee
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