Compound Angles

[Joe Bartok]

Well, considering the time of year, everyone’s soon going to have better things to do. I’m going to be offline myself for most of the holiday season.
Before I go, here’s a topic that may be of interest: Compound Angles. If no one’s asked this question yet, it’s a sure bet it will come up in the future. The subject has probably been covered before in books or on the www anyway, but here’s my bs version. The material in this file actually appears in three different guises in my website, but for convenience I’ve compiled it as one document. Said website will be undergoing a HUGE edit next year; there’s a zillion things that need to be fixed. Among them, terminology, and now I’ve got some questions. Much of this material was actually created in my pre-computer and/or pre-Internet days. Sometimes I didn’t know the correct name to apply to a quantity, and often just made one up. If anyone cares to, check out the names I’ve used, and correct me if necessary.
MITER: This one I’m certain is being used correctly.
BEVEL: Not so sure about this. Some material I’ve read since creating this terms what I call the BLADE ANGLE the BEVEL.
ANGLE on COMPOUND FACE: ??? Is there a correct name for this? I’ve been told it’s a “cross-cut” angle, but I don’t think the person I was asking understood my question.
DIHEDRAL ANGLE: This one’s correct.
BLADE ANGLE, or SAW BLADE ANGLE: Is this the right term, or is there a better name for the blade angle setting on the gauge?
If anyone needs to calc saw blade settings, there’s a Saw Blade Angle Calculator at:
http://ca.geocities.com/xpf51/ANGLE_CALCULATORS

[Joe Bartok]

Any industry standard definitions for the terms used in the last post (bevel, saw bevel, angle on compound face)? The file posted Dec. 24th has been updated: I've added the definition of a dihedral angle, another development, and a couple of sample calculations.
Looks like this file will have to be re-done at least one more time anyway. The pdf creator converted objects that were "semi-transparent" as filled, so there were parts of some images lost in the translation.

[Rich]

Damn - nice work Joe.

[Joe Bartok]

Hopefully someone can fill me in on what the correct terms are on the list on my previous post. This is one of the reasons I've signed up for, one of the things I hope to learn here.
I already went through this process trying to assign correct names (what I think of as "industry standard terms") with the angle calculators. The best I could find, the most widespread and commonly used, are the Hawkindales. Unfortunately, I've got about thirty-five different possible angles, and my efforts to integrate the "standard" names in my worksheets and calculators weren't entirely successful.
Another thing I'm trying to learn is to make a document such as this clear and readable for potential readers. In this case, I've left out solutions using vector products. This is another way to solve dihedral angles, but it's not relevant here, and would be confusing. I have included trig solutions, which are kept as basic as possible, geometric solutions for those who don't like trig, and examples that can be used as a "template" by people who might be uncertain as to how to apply the math. But, if anything I've done doesn't make sense, isn't clear, or there are errors, go ahead and say so.

[Rich]

Your term definitions make sense to me in context with your diagrams and calculations. Bevel is what I consider the vertical angle between the table and the saw blade - so I believe you are using it correctly. The angle on compound face makes sense and I understand it - not sure what else it could be called though.

Genius makes it's own rules which includes naming conventions :)

[Joe Bartok]

Guess I'll have to live with that (not too sure about the genius, though). Sometimes the terminology even in math or physics texts isn't consistent. In fact, speaking of standard names for Hip/Valley angles, there were a couple of different systems developed at about the turn of the century (the 1900's) in the steel detailing industry. And I suppose it's pretty tough to define and name every line, angle, or other nit-picking detail we might run into during drawing or construction!
Anyway, I'll fix this file up and replace the current version with the new version early next year. In future, if anyone asks a question related to compound angles, here's the answer.

[wood-79=worker]

Dear Joe,
I bookmarked this page as a link to access your excellent work on compound angles. It has helped me to solve hip roof problems and helped to educate me on the complexity of cutting compound angles in other situations. I have a pretty good math background, but if you don't do this stuff every day it slips away. Well, once again I am working on a solution to a new issue, and find to my dismay that the links to your yahoo geocities sites are all null. Apart from searching the web archives, I am wondering if you have moved the information elsewhere, or whether it is simply no longer available.
Thanks for all the work you have done to help the head-scratching carpenters of the world...
ps In today's world of sliding compound miter saws, it may be clearer to refer to miter guage versus bevel guage settings when you talk about setting the blade angle. You've probably long since resolved that question, though, when I think about it

[Joe Bartok]

The information is still online. The new URLs may be found in this post ...

http://www.construction-resource.com/forum/showpost.php?p=51774&postcount=10