Sorry to bother you all with this question, however have not been able to find the answer at the tool store(s). So the question is really very simple, but for the life of me can not think of a reason for the angle given. The question is given a 6/12 or 6 inches of rise for 12 inches of run gives a 27 1/2 degree. angle for a cut. Great that does not make sense to me at all. since a 6/12 = .5 and the arcsin of .5 is 30 degrees. Could anyone please explain to me the difference?
Thanks in advance,
Mike
Replies
You must have been asleep in trig class.
Take the test again. You can open your book this time.
What is the definition of SIN?
That will show you your mistake.
Thank you daaaaaaaaaa...got it now was thinking tangent
sohcahtoa...... the indian princessMike Smith Rhode Island : Design / Build / Repair / Restore
mike i looked at some of my visuals and they say the angle is 27, not 27 1/2
so i punched it into the CM.. and it says 26.57 deg.
You have to do Tan-¹(6/12) = 26.57° not Sin-¹1 (6/12) = 30°
joe.... can you post that site where i bought my CM + trig ?
fred is looking for oneMike Smith Rhode Island : Design / Build / Repair / Restore
Saddle Our Horses
Canter Away Happily
Toward Other Adventures
Sine = Opposite / Hypotenuse
Cosine = Adjacent / Hypotenuse
Tangent = Opposite / Adjacent
Draw your triangle and you'll see that you have the opposite (6) and adjacent (12) sides given so you are looking for the tangent.
6/12 = .5000 = tangent for 26.57 degrees (using Mikes figures - my tables don't go that far)
Mike, you said you looked it up with your CM. What's a CM?
oldfred
Construction Master calculator
Construction Master calculator
Looks like another item on my gotta-have toy list.
oldfred
my second one.. i sent my CMIV to australia with mark..
and bought the CM + trig after these guys talked me into it
Mike Smith Rhode Island : Design / Build / Repair / Restore
Thanks, I'll see if I can find one and check it out.
oldfred
Fred,Here's the link for the Construction Master Trig.http://www.amazon.com/exec/obidos/tg/detail/-/B000059S5K/qid=1109322056/sr=1-1/ref=sr_1_1_etk-tools/002-4062753-3034406?v=glance&s=hi&n=228013Here's the link for the case which is a must because I've drop my Calculator plenty of times and for the price it's not worth breaking like I did with my first one.http://www.calculated.com/productcart/pc/viewPrd.asp?idcategory=9&idproduct=60Joe Carola
joe.. you know. i was wondering about that..
cause when you and i talked, the link was to another place
i bought mine from that other place... and it came with the case..
then about two weeks ago, i went back there and couldn't get a price on the "+ trig"...
wonder if they decided to stop competing with Amazon
Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike,Your right because I gave you the website to "Calculator Warehouse" and that's where I bought my second one because I drop the first one and broke it because I had no case. The first one I ordered from "Calculated Industries" the company who makes them. They're 10.00 more.
http://www.calculated.com/productcart/pc/viewPrd.asp?idcategory=0&idproduct=22Did you get the Armadillo case with yours or a different one?The Armadillo case is nice because it's a hard rubber and if it falls it just bounces.Joe Carola
Joe,
I've been using the case for awhile and it has saved my CM more than once. I had the yellow and grey case, and then when Jasen came back to work, I got him a new CM w/black case. The lid wouldn't close, so I took that one and gave him my case, and then realized that the lid didn't close on mine either :-)
Those cases are nice because you can write measurements on them. I've really come to rely on that.
I keep a spare CM at home in case I break mine on the job and I have the desktop CM Pro.
Tim,I have the Desktop CM Pro DT also. What's good about that is it has every function the CMP Trig has plus three more {Yards] [Footings] [00]. No case for that bad boy though and also the top tilts up to about 41.86°...................;-)Joe Carola
joe.. i measured a photo of that desk unit, with my Bosch angle measurer...i think your 41.86 deg aproximation is a little off..
try 42.03....
hey
http://www.calculatorwharehouse.com
my Trig Plus III came with a black & grey armadillo case.. with Calc Wharehouse stamped on it paid $79.36 , but there was some kind of rebate
when i bought my first CM Pro at HD i got a coupon for a blue & buff armadillo case.. i think it was $5.. mailed it in and got it.. worked great.. sent it to australia...
works fine there.. since it's got meters and MM besides the feet and inches
so, joe... you and fusco gonna make plans for ohio in august ?
Mike Smith Rhode Island : Design / Build / Repair / Restore
Tim, I honestly don't know what that calc is good for. I gave it my best try and decided that for rough framing my $5 dual power, with separate memory buttons and sq rt key if far better.
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
It looks cool?
I like working in ft/inches and with the trig functions, you can't beat this calculator for roof framing. Every house we work on is stick framed with the exception of maybe one a year being trussed. It pays for itself in spades when roof framing.
Check out the "gang cutting" thread at the end. I posted pics of the house we finished a week and a half ago. For that roof, the CM makes life a lot easier. I figure the simpler I can make the process, the less likely I am to screw huge :-)
I have to go to work now. A 2002 Ingersoll Rand VR1056 is being dropped off for us to demo and I can't wait :-)
blue.. i got a copy of "A Roof Cutter's Secrets" since my new mentor , Tim, recommended it..
almost every calc in the book has a little symbol at the bottom of a Calculator... this symbol means that if you turn to appendix B, it will show you the faster way to do the same calc with the CM IV, Trig Plus II, Trig Plus III, or the CM Pro..
the book is great.... i got one off Amazon.. and it really makes the calculations pretty simple to follow..
hey.. i wanna start a thread about Marketing and the books that have helped us the most...
i want a review from people that have actually read the damn things.. jsut having it on your bookshelf don't countMike Smith Rhode Island : Design / Build / Repair / Restore
Mike, I gave that CMIV an honest look. It was great at figuring out how to calculate the common rafter and the hip, but that's where it ended. There was no easy way to morph or transition into related tasks. Maybe my techiques and methods of calculating roofs and their related calculations are so imbedded into my head that I can't changeover...I don't know. All I know is that when I tried to do some of the very simple things that I take for granted with the CMIV, that I routinely do with the cheapie, it wouldn't work.
And so, I highly recommend learning the basic geometry that goes into the calculations of a house frame and do it with the cheapie. The CMIV is not a shortcut for simple houses. IF you have to frame a parabolic dome, with irregular intersecting cathedrals, then I suppose it's time to pull out the science thing. IF you simply need to get a very basic ridge length on a 12/12 layon, then use the cheapie.
blue Just because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
i don't believe it.... i've had other calculators for years.. ever since i retired my slide rule.. and the CM just makes it faster and easier..
i've got a TI sitting here, gathering dust
i've got a Casio sitting here, gathering dust
i'll walk all the way across the room to get my CM PLus III rather than pick up one of the older onesMike Smith Rhode Island : Design / Build / Repair / Restore
i've got a TI sitting here, gathering dust
i've got a Casio sitting here, gathering dust
I'd let them gather dust too. They have way too many buttons and functions for my tastes. Rough framing isn't all that complicated. There are actually very few functions that you routinely need and keeping it simple is the best policy. I think it's important to understand that most of the calculating I do is in conjuntion (not instead of) with already established points in the frame. That lends itself to very basic calculations, most of the time, and a lot of the calculations are unnecessarily complicated by the "smart" calculators.
Here's a pic of the only one I want in my possession. They can get rid of the percent button if they wish...
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Framer and Mike,
Thanks for the help and the websites. I checked out both sites and the calculator is on my list. Looks like it will be a lot of fun to use.
oldfred
I guess this question and all the posts that follow is proof that when you mix complex math with contractors you might have problems. I know a guy who memorized all the diagonals on the rafter square from three and twelve and twelve/twelve pretty impressive. I wanted to be really impressed so I gave him a span for a rafter and asked him for the diagonal he scratched it out on a 2x4 he was an 1 1/4" off . don't get me wrong I like knowing why --but why? 15' 6" RUN - 8 INCH PITCH AND HIT DIAGONAL and it spits out the number that's why I like my construction master v --also off the subject but another thing I like about the CM calculators is if you want 3 1/2" under a window for flashing purposes all you have to do is put in the rise and the run and then punch diagonal and it will give you the length of the rafter and then hit pitch and it might be a 6 1/4" pitch --pretty handy and very quick
Rob, that was a bad example...I needed 11 pokes on the CMIV to get my answer and only 10 pokes on my $5 cheapie!
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Explain? I'm curiuous how you did it the only way I know to get diagonal measurements is a squared + b squared = c squared but I haven't used that method mutch . I guess I just like working in feet and inches , but I would like to know?Thanks -Rob
Actually Rob, I guess I mentally did a shortcut.
When I think of an 8 pitch, I automatically plug in 208, then the sqrt symbol. That equals 4 strokes.
YOu example was 15' 6". I mentally shortened that to 15.5 units x 208 sqrt = 223.56" or somthing or other.
Like I said, that was a bad example....
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Blue,
You know, a CM Trig Plus calculator and pretty good working knowledge of stick framed roofs is faster, than a scientific calculator with the same experience. I bet if you stick framed every house you were on, you would switch to a CM.
Reason I say that is that you seem good at getting rid of wasted steps in the framing process and as you whittled down your calculating, cutting and then stacking process, you would be using a CM.
By the way, check out the pics I posted in the Gang Cutting thread of our modified Headcutter http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=53222.54