My meager math skills fall short of getting this calculation.
I'm pretty sure any old calculator can get this but knowing what to feed it is whats missing.
I've figured a compound angle to join a 2x4 frame of 16" square. with the 4 side verticle ... (on edge)
Now to keep the top side parallel to floor...
A quicky ascii art diagram: ____________ _____________
-------------------------\ /------------------------------ \ / \ / -----------------------------\ /--------------------------------------- a b Those two angles are not the same:
a= 78.69 and b=84.28. You have to imaging the 45 degree mitre not shown. But when the parts are layed together at a 90, the top side leans inboard so it isn't parallel to an imagined floor.
These are 2x4 lumber, how can I figure the angle of cut for the top 2in wide side, so that it ends up parallel to floor?
"Wood Butcher" wrote in news:MQDhc.273$YP5.46217@attbi_s02:
WWRD? = What would Roy do?
I like your thinking, Art. I often ask myself how my grandfather, a Danish-immigrant blacksmith, would have done solved a problem. HE never took trig, that's for sure. And he was the hardware supplier for the area, for the most part.
Exactly! I was born with a head for math (no fault of mine ) and have successfully vanquished many an equation with enough Greek symbols to start a library. But in woodworking my bevel gauge is my constant friend. Who cares how Einstein would have done it? Set the bevel, draw the line, cut it, and finish it. ;-)
snipped-for-privacy@newsguy.com wrote in news: snipped-for-privacy@newsguy.com:
You can safely assume that if we know how to solve the problem adequately in several acceptable ways that we can only screw up with extreme effort, that anything 'more elegant' is 'left as an exercise for the students'.
Heck. I have a degree in Economics. One of the classic phrases of that art is, uttered while waving the left hand in the air, "It can be shown that....", and proceeding as though truth had been established, without ever, in fact, proving, or sometimes, even supporting, the contention.
You got at least one good answer. It's worked for years. You want more, get a hold of a good book on classic Chinese joinery.
Well, I stumbled into this thread late, but when "Roy" comes up around here, it's usually in reference to Roy Underhill from The Woodwright's Shop - neander-extraordinaire.
Nothing wrong with that. I've had a degree in math/physics for more years than I can count. What turns my crank is that you can draw an ellipse with two circles and a straightedge; the art of descriptive geometry [layout ...the sort of thing being discussed here, but more, like the tinsmith forming and joining round tin tubes at an angle]. And who doesn't know about "The Carpenter's Square", a book that shows you how to layout and build spiral staircases?
Has anyone seen that 'simple' table from IKEA? Don't laugh until you've designed one yourself. It's a rectangular top. Turn the top
90 degrees and fold it open to double the size. Two questions: 1. Where do you put the pivot point? 2. what ratio of sides so that the open table has the same shape (but larger) as the original? I can figure that out easily, I can then tell you easily, and you can do it easily (likely much better than I could), and don't forget why ...the math that is needed to figure it out in the first place. But I would (and do) come here for the experts who can tell me what type of material goes with which, and which kind of pivot support is best, and a whole mess of other useful information. I don't knock that. I absorb it and someday use it.
I like nothing better than applied math. However, don't forget that is what it is, "applied". So don't knock it completely. As human beings we are not satisfied with just a little. We want all the bananas. My background is blue-collar steelworks. It pays to have both feet on the ground *and* to know the reasons why. Always keep an open mind.
You have tables of compound angles available, just handed to you. So use them. There's nothing wrong with that either, and you don't need a helper with the shakes. You just need to know how to read. My father was also a highly skilled tradesman, and I listened to him too. It's called "tricks of the trade", and we learn something every day.
I see people are havuing a high old time with my question. Let me explain a bit:
I've spent 35 yrs as field construction Boilermaker and pipe fitter/welder. Now retired. I've had plenty of experience with the `hold it in place and scribe' technique and am well aware of its uses and benefits.
Now I'm old and partially crippled. I tinker almost exclusively by myself. I wanted to just set the saw to an angle and start cutting.
No drama, no fuss. I'm pretty sure this angle of cut can be established before hand with a light weight calculation of some kind. I'd hoped someone here would know it.
Heh, me too. It really prepared me for the world of application integration and a woodworking hobby :) I have to stop myself from thinking about the wood commodity market while picking out boards...
Your comment reminds me of an old economist joke:
An economist, an engineer, and a physicist go out camping together. The day gets long and they start getting hungry, so they get out thier stash of canned food and realize that they forgot a can opener. They all think about it for a minute.
The physicist says "I know! we can put the can in the fire. Eventually heat will build pressure and the can will not be able to hold the pressure!"
The engineer replies "Yes, but then we'll be covered with cream corn. How about we bend that sapling over there to create a tensioned lever. We stap a pointy rock on the end of it and brace the can on a rock on the ground. Accounting for wind changes and the angularity of the can to the ground, we precisely release the tension in the sapling causing the rock to accurately remove the top from the can.
The economist says, "Sounds way to complicated to me. There's got to be a better solution. (long pause) Okay! I got it....
"Assume you have a can opener..."
Jay
Let the booing begin! I'll also be waiting for the "Neander, Normite, and rough carpenter" version of the tale.
I offered to post one here a while back I did myself as an Excel spreadsheet, or just the printout if you wanted, but that's frowned upon. I'll look for some other way. A PDF is fairly tiny but someone would bitch even then.
Please be aware that many news servers automatically strip any and all attachments to anything that was posted in a non-binary group. So even if nobody objected to your posting binaries here, it wouldn't work anyway. It has nothing to do with the size of the file, and everything to do with the fact that there are binaries groups for binary posts, and non-binary groups for text-only posts.
Besides which, there already is a binaries group set up *specifically* for posting woodworking-related binaries: alt.binaries.pictures.woodworking, or ABPW for short. The accepted procedure is to post your picture, spreadsheet, pdf, or whatever to ABPW, and post a note here alerting people to the post in ABPW.
-- Regards, Doug Miller (alphageek-at-milmac-dot-com)
For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com
Go to alt.binaries.pictures.woodworking and post away!
That's what it is there for ... binaries don't just limit you to pictures. Keep in mind that many folks will be skittish about downloading a document, other than a .pdf, that could contain a virus of some sort.
What's your issue with a 'helper'? A clamp is a 'helper'. Even a pile of rocks can be a 'helper'. It would seem that you made the bad assumption that a helper had to be the live kind.
You're not safe in your assumption about me not knowing the mathematical answer either. With degrees in electrical engineering I'm no stranger to this kind of basic math. It just isn't necessary to solve the problem.
Art
"Make everything as simple as possible, but not simpler." - Albert Einstein
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