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01-16-2012, 08:07 PM   #16
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Must be getting old. Can't remember brand names today! Anyway, do they still make the mini chainsaw tool that cuts multiple birds mouths with the rafters stacked on their sides. I think it was the same company that made the tool for routing out old putty from window sashes.

01-16-2012, 08:51 PM   #17
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Quote:
 Originally Posted by titanoman What are you talking about? Is that a real question or are you making jokes that are going over my head?
You said it didn't make sense to you, so I was giving you a hint, roof meister.

01-16-2012, 08:56 PM   #18
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Quote:
 Originally Posted by abracaboom You said it didn't make sense to you, so I was giving you a hint, roof meister.
You're just making stuff up.
Makes no sense.
There is no such formula like that. I guarantee it.

01-16-2012, 09:02 PM   #19
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Quote:
 Originally Posted by titanoman Length of plumb cut times the square root of two? Makes zero since to this roof master.
He's talking about the square root of 2 times the length (in inches) of a square will always give you the diagonal measurement. Only works to figure out the diagonal of a square. Therefore when figuring out the diagonal distance on the birdsmouth for a 12/12 pitch rafter....the OP can multiply the seatcut for example if it is 3-1/2" he can multiply that times the square root of 2 and that will be his diagonal measurement on the bottom of the rafter from the bottom of the seatcut to the bottom of the heel cut.
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Last edited by Joe Carola; 01-16-2012 at 09:10 PM.

01-16-2012, 09:08 PM   #20
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Quote:
 Originally Posted by Joe Carola He's talking about the square root of 2 times the length (in inches) of a square will always give you the diagonal measurement. Only works to figure out the diagonal of a square.
A square plus B square = C square.
Has absolutely nothing to do with figuring a seat cut.

01-16-2012, 09:15 PM   #21
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Quote:
 Originally Posted by titanoman A square plus B square = C square. Has absolutely nothing to do with figuring a seat cut.
Read my post #19 again and you will see that is does for a 12/12 pitch roof and his seatcut that the OP is talking about. I don't do seatcuts that way but the OP was asking and that is the answer for a 12/12 seacut along with the square root of 2 that abracaboom was talking about that you said made no sense when it does for that situation.
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01-16-2012, 09:21 PM   #22
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Quote:
 Originally Posted by Joe Carola Read my post #19 again and you will see that is does for a 12/12 pitch roof and his seatcut that the OP is talking about. I don't do seatcuts that way but the OP was asking and that is the answer for a 12/12 seacut along with the square root of 2 that abracaboom was talking about that you said made no sense when it does for that situation.
I guess. But I think we both know that's kind of a silly approach, using wicked math, instead of figuring one the way you would any other pitch.

01-16-2012, 09:24 PM   #23
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Quote:
 Originally Posted by titanoman I guess. But I think we both know that's kind of a silly approach, using wicked math, instead of figuring one the way you would any other pitch.
Yes....but the guy asked. Framing square is all you need to mark a birdsmouth.....someone wants the math....not a problem...
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 01-16-2012, 09:26 PM #24 Newbie   Join Date: Dec 2011 Posts: 19 Rewards Points: 10 thanks everyone for the advice, i really appreciate it. for most folks who replied i think it sounds like cutting one rafter at a time and being really precise and prideful on my cuts.
 01-16-2012, 09:33 PM #25 Member   Join Date: Feb 2010 Location: Oklahoma Posts: 992 Rewards Points: 506 Titanoman - abracaboom is way out of your league (and mine). His (her?) math is not wicked, it is the BASIS of all architecture, engineering, and construction. He (she?) politely schooled me in a thread titled Gambrel Math. Check it out. He (she?) could teach us a lot if we heed his (her?) wiley hints. Last edited by jlmran; 01-16-2012 at 09:35 PM.
01-16-2012, 09:50 PM   #26
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Quote:
 Originally Posted by jlmran Titanoman - abracaboom is way out of your league (and mine). His (her?) math is not wicked, it is the BASIS of all architecture, engineering, and construction. He (she?) politely schooled me in a thread titled Gambrel Math. Check it out. He (she?) could teach us a lot if we heed his (her?) wiley hints.
No sir. You don't use square roots to figure bird mouths. He'll tell you that. He's just saying it happens to work in a 12/12 because they are both (plumb and level) 45° cuts.

He might be out of your league, but nobody knows more about cutting a roof in than me. I'll tell you that right now. And I don't use a book
or a framing square. I use my brain.

Go back and look at a few pictures I posted about stud lengths, or the difference between using 2x4 and 2x6 for walls I think.
I designed that roof and cut every damn rafter on that thing.
Just an example of what I'm used to.
(this is the roof on the house

01-16-2012, 10:16 PM   #27
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Quote:
 Originally Posted by titanoman but nobody knows more about cutting a roof in than me. I'll tell you that right now. ]
Thats pretty funny. You actually believe that. I've been cutting roofs for almost thirty years and would never say that. Ive been on several roof framing forums with alot of great roof cutters and not once heard any of them say that.
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01-16-2012, 10:23 PM   #28
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Quote:
 Originally Posted by titanoman No sir. You don't use square roots to figure bird mouths.
OP asked how to determine the length of the birdsmouth diagonal. It appears there are two ways to do this. Both methods were presented here. Sure, one method is far more practical for use in the field (measure/draw and snap a line), but the other method (calculation) is no less accurate.

In fact, it seems that calculating the length of the diagonal might serve as a good way to check the correctness of the BMs layout.

01-16-2012, 10:42 PM   #29
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Quote:
 Originally Posted by Joe Carola Thats pretty funny. You actually believe that. I've been cutting roofs for almost thirty years and would never say that. Ive been on several roof framing forums with alot of great roof cutters and not once heard any of them say that.
Do you really think that I think they're is nobody on this earth as good as me?
I was going to an extreme in response to the poster that said I'm out of somebodies league.
There are millions of houses with some pretty cut-up roofs on them that I didn't build, so obviously I'm not the only guy that knows how to build a roof.
Geeze..

01-17-2012, 08:12 AM   #30
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Compared to the master carpenters of old, we are nothing but apprentices of the worst kind: those who believe they know it all.

All roof cutters should watch the movie The Pianist. The roof frames from old Warsaw it depicts, even if simple-looking from the outside, run circles around any funky-looking modern roof frame.

The older I get, the less I care about what things measure. You can build a house without a tape measure, letting each piece be what it is in relation to others.

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