Ive noticed that when calculating the length per single unit foot run using the Pythagorean theorem vs the length per foot run listed on the carpenter's square, it's off by .02" or 1/32. This isn't such a big deal on one unit length but when you multiply that over 1/2 the length of a 40 ft building, that 1/32 turns into a half inch. So, you could conceivably cut your board a 1/2 too long or too short. How does one account for this? A half -inch short if you use the square multiplied vs Pythagorean Theorem
You are correct in asking this .. The teachers response .. " The students don't always have a square at home " is hogwash .. and you are a scant few that has brought this up in all my trolling of these masters .. Just being off a wee bit translates into a 1/4 " or even 9/16" .. and that is dramatic I can do the math to an absolute and show the error .. The greater the span , the greater error will .. Will cause a problem .. The Square method works on little homes and backyard sheds .. But again ... The greater the span , the greater the error .. and if I not mistaken .. Teachers should teach absolutes .. not errors .. Use Math . Use Pythagoras .. .I would give you an A just for asking that question .. .. My blackboard is a sheet of plywood , during lunchtime with an inquisitive mind ..
Don't lay it off one foot at a time with the rafter square. Multiply the length per foot run times the rafter run with a calculator. Then measure it with a tape measure. Use the square to get the last inches after you measure the feet with your tape.
Yes. Valley rafters and hip rafter on an equal pitch roof are the same thing. We do not drop the hip. and typically make just one cheek cut on the tail to carry the fascia board...an inverted double cut would be...silly.
Thanks for this video. I just have two questions, how is the line length 18 inches and why is the number of units 4? Thanks. Just a little confused at the numbers on the white board
sorry about that comment,you did in fact cover dropping the hip,I was on the classic work site and ended up putting that comment on Brads sight.Very good video,watched it at least 10 times very carefully.
you didn't mention cutting the seat cut a little deeper so as to allow the hip to come into line with the other rafters to aid in sheeting,have you heard the term backing? I understand backing isn't done anymore,and the hip is just dropped to achieve the same result.
when you measure 5 1/2 right at the end that would be wrong. cause the plumb cut on a 2x6 is more than 5 1/2" at 6/12 pitch and you would want to measure at the peak my friend!
Christopher W the tops of all the rafters have to meet up. This means the seat of the hip is the same distance down from the top of the hip rafter as the common...then the hip drop.
I'm on about existing buildings and in my country England ( u know the country where you get your language from) bricklayers build many of the walls so my aforementioned point is sometimes the case . If I were framing the walls on site or some nice dry classroom of course they would be spot on .
Ray Finkle I agree with you, that on renovations there can be some issues that require careful measuring. I don't just teach...I build too...outside....in the heat....in the rain....in the cold. Still get it, "spot on". Thank you for your comments (and of course this language).
refrigeration tech, no. when on one side of the hip you have a steeper slope than the other side. quite a few home have a hip roof with the ends at a greater slope than the front and back. if this is the case we say the roof is unequal. on an unequal roof the hips do not travel at a 45...they don't cross over the corners of the wall....the end wall needs to be built up or a post put under the hip.
Not always !! .. If one side is 4/12 and the other is a 6/12 .. The hip is offset on the same plate line and the Seat depth is adjusted as.. It matters whether the size of the rafter is a 2x6 or a 2x12 so you don't chomp out too much in a birdsmouth " Per Code " .. LOOL .. Plates do not always have to be lifted !!
Brad, other videos are indicating that the second plumb line (HAP CUT) is measured from the center line of the cheek cuts. You measured 2-1/8th further back which was from the end of the rafter. Seems your rafter is going to be short? Which is correct?
![How To Make Common Rafters [Measure, Mark & Cut]](/img/1.gif)
This is not the union way
Very good video, at 4:12 you show dropping the seat cut another 1/4" (1/2) thickness of hip stock. Why is this done, what does it accomplish?
Excellent video, one of the best explanations.
Ive noticed that when calculating the length per single unit foot run using the Pythagorean theorem vs the length per foot run listed on the carpenter's square, it's off by .02" or 1/32. This isn't such a big deal on one unit length but when you multiply that over 1/2 the length of a 40 ft building, that 1/32 turns into a half inch. So, you could conceivably cut your board a 1/2 too long or too short. How does one account for this? A half -inch short if you use the square multiplied vs Pythagorean Theorem
The students don't always have squares at home. In class and in the shop we always go with a framing square...
+buildingreno great thanks for the reply. wish I could take a class. Is the Mohawk college referenced in Canada?
You are correct in asking this .. The teachers response .. " The students don't always have a square at home " is hogwash .. and you are a scant few that has brought this up in all my trolling of these masters .. Just being off a wee bit translates into a 1/4 " or even 9/16" .. and that is dramatic I can do the math to an absolute and show the error .. The greater the span , the greater error will .. Will cause a problem .. The Square method works on little homes and backyard sheds .. But again ... The greater the span , the greater the error .. and if I not mistaken .. Teachers should teach absolutes .. not errors .. Use Math . Use Pythagoras .. .I would give you an A just for asking that question .. .. My blackboard is a sheet of plywood , during lunchtime with an inquisitive mind ..
Don't lay it off one foot at a time with the rafter square. Multiply the length per foot run times the rafter run with a calculator. Then measure it with a tape measure. Use the square to get the last inches after you measure the feet with your tape.
Thanks, from Nairobi kenya
Do u do the same with shortening the valley?
Yes. Valley rafters and hip rafter on an equal pitch roof are the same thing. We do not drop the hip. and typically make just one cheek cut on the tail to carry the fascia board...an inverted double cut would be...silly.
Love the videos, and especially the clapping when your done!
What if it's not a 2by? Will it still be inch and a 16
No. It will always be /2 of the 45 degree thickness.
Thanks for this video. I just have two questions, how is the line length 18 inches and why is the number of units 4? Thanks. Just a little confused at the numbers on the white board
The fractions are confusing for those of us who use the arithmetic measuremennts.
quit saying aGAIN! great vid otherwise
Lol
sorry about that comment,you did in fact cover dropping the hip,I was on the classic work site and ended up putting that comment on Brads sight.Very good video,watched it at least 10 times very carefully.
Please do not use the same camera man again.your vids are really good but the cameraman as no clue what hes doing..
Suki Singh thanks for your comments.
Buen vídeo pero me gustaría que lo traducieran al español gracias
you didn't mention cutting the seat cut a little deeper so as to allow the hip to come into line with the other rafters to aid in sheeting,have you heard the term backing? I understand backing isn't done anymore,and the hip is just dropped to achieve the same result.
Hip drop. And yes i have heard of backing the hip. I do mention dropping the hip.
you sir are a champion wish i would have seen this years ago. i learned the hard way thanks for sharing
Muy bueno tu video teacher
Is there a standard dimension for birds mouth sizing? Great tutorial!
In Ontario the common rafters needs a horizontal cut of no less than 1.5" or more. Once you make your common rafters the hip bird's mouth will be set.
when you measure 5 1/2 right at the end that would be wrong. cause the plumb cut on a 2x6 is more than 5 1/2" at 6/12 pitch and you would want to measure at the peak my friend!
I thought the seat cut could not be more than 1/3 the width of the beam. Is that different when framing a hip roof?
Christopher W the tops of all the rafters have to meet up. This means the seat of the hip is the same distance down from the top of the hip rafter as the common...then the hip drop.
Farina Marcina for common rafters. Not hips or valley rsfters
Need stair gauges
Audio is terrible.
Thank you, Professor!
A good video. But we all know that u have to have level , parallel and square wall plates and that is not always the case
Ray Finkle if you're framing the floors and walls,why would they not be square and level?
I'm on about existing buildings and in my country England ( u know the country where you get your language from) bricklayers build many of the walls so my aforementioned point is sometimes the case . If I were framing the walls on site or some nice dry classroom of course they would be spot on .
Ray Finkle I agree with you, that on renovations there can be some issues that require careful measuring. I don't just teach...I build too...outside....in the heat....in the rain....in the cold. Still get it, "spot on". Thank you for your comments (and of course this language).
albatrossus albatrossus yeah never thought of that
are cheek cuts always cut using 45 degrees?
if the roof is equal pitch.
you mean 12/12?
refrigeration tech, no. when on one side of the hip you have a steeper slope than the other side. quite a few home have a hip roof with the ends at a greater slope than the front and back. if this is the case we say the roof is unequal. on an unequal roof the hips do not travel at a 45...they don't cross over the corners of the wall....the end wall needs to be built up or a post put under the hip.
The side cut angles for all pitches are stamped on your framing square. They are not all 45 degrees.
Not always !! .. If one side is 4/12 and the other is a 6/12 .. The hip is offset on the same plate line and the Seat depth is adjusted as.. It matters whether the size of the rafter is a 2x6 or a 2x12 so you don't chomp out too much in a birdsmouth " Per Code " .. LOOL .. Plates do not always have to be lifted !!
Brad, other videos are indicating that the second plumb line (HAP CUT) is measured from the center line of the cheek cuts. You measured 2-1/8th further back which was from the end of the rafter. Seems your rafter is going to be short? Which is correct?
The 1st line back is shortening. The 2nd and third are for cheek cuts.