If I was to build a square box, beveling each side at the corners, I’d use 45 degrees on the table saw.
Now if that box was to be a pyramid, could I just draw my tapers on the boards, and run them through that same 45 degree angle with a jig to hold the taper? Or would I need some different angle on the bevel?
Part of me says that 45 should work but part of me says perhaps not.
Replies
I think you need 60deg angle for a triangle. 4 90deg= 360 deg. 3 corners=? 120deg or (half that) 60deg.
Family.....They're always there when they need you.
4 sided pyramid. 44.5 to 44.8
3 sided pyramid 59.5 to 59.8
david
45 degrees won't work.
Here is a calculator to determine the angle: http://www.1728.com/volpyrmd.htm
That's what I love about this place. No I have a link for the bevel angle of a pyramid! LOL
Pardon me if my geometry is rusty, but there is no law that says that the angle between a face and the base of a pyramid has to be X degrees. You could use a 1 degree bevel or a 89 degree bevel and you would still wind up with a pyramid. Just depends on how high you want the apex.
the older pyramids of egypt had a slope angle of 43 1/2.... the more modern ones had a 52 deg slopeMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Pyramids based on the "magic" 3-4-5 triangle had a side angle of 53.13°. The base was a multiple of 6, which made the cross-sectional area the sum of 3-4-5, the base perimeter twice the sum of 3-4-5, the area of the base three times the sum of 3-4-5, the volume four times the sum of 3-4-5, and the area of the four sides five times the sum of 3-4-5.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
I think you're right, with the criteria of the pyramid being equal legs on the base and then the triangles of the sides being isoceles triangles. Nothing mandating that the sides be equialateral triangles. So any angle of the sides to suit the builder as long as that angle is constant on all the sides.
Here ya go:
http://www.woodworkersguildofga.org/ShopHelpers/MiterCalculator.htm
Mike Hennessy
Pittsburgh, PA
I have these two calculators to find the miter gauge angle and blade tilt.
http://www.josephfusco.org/Calculators/Box_cutter.html
http://www.josephfusco.org/Calculators/Advanced_Box_Cutter.html
http://www.constructionforumsonline.com
Depends on the dimensions of the box, i.e., the Rise/Run, and the Corner Angle.
View Image
Enter your numbers in the Framing and Joinery Angle Calculator. Here are the formulas, where "Pitch Angle" is arctan (Rise/Run) and "Plan Angle" means ½ Corner Angle ...
C5 = arcsin (sin Pitch Angle × cos Plan Angle) ... Saw Blade Bevel Angle
90° – P2 = arctan (tan Plan Angle ÷ cos Pitch Angle) ... Angle measured on the face of the Pyramid
The above is assuming equal slopes for each side of the box, and you are mitering the joints. Or were you looking for the formulas for a butt type joint?
Edited 12/17/2008 12:20 pm ET by JoeBartok
Edited 12/17/2008 12:23 pm ET by JoeBartok
Edited 12/17/2008 12:25 pm ET by JoeBartok
4 sided (5 including the base) 45º
3 sided (4 including the base) 60º
Geoff, in essence this is the same as your question ...
Angle help needed- brain stopped workingJoe Bartok
For a tight fit on the edges (corners)
you have to stay 1-2 degrees less than 45 or 60.
david.
Don't you mean MORE than. 45 0r 60..? Seeems to me over beveled would have the face points meet firster.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Yup! Or more righter!
That makes for a more betterer looking Pyramid.
I should know, I built one..well actually mine was "Timber framed" scale model.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
So do knives really stay sharper in a pyramid? Side topic-
You following the whole "Nothing" astrophysics thing?
That whole "Pyamid Power" thing is "Only if you believe it hard enough" I'd say most has been proven as bunk.
"nothing" astrophysics? I don't follow..?Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.npr.org/templates/story/story.php?storyId=5198071Some new Dark Matter thoughts.
Then there's the Coriolis Effect -- it's a proven fact that when they make margaritas in Australia, the blenders turn the other way!AitchKay
The rooms spin the other direction as well.
TFB (Bill)
That whole "Pyamid Power" thing is "Only if you believe it hard enough" I'd say most has been proven as bunk.
Tell that to Tutankhamen.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
A knife stored under a pyramid never ever gets dull. Never. It also doesn't get dull stored under any other kind of shape.
It only gets dull when you use it.
To prove or disprove this theory I think the person should wear a pyramid on their head when using the knife. Then report back.
Roger, I'm on it.
Nobody seems to really know the answer to this one.
What angle did you use when you built that one in Giza?
Mike
Small wheel turn by the fire and rod, big wheel turn by the grace of god.
The Giza pyramid, if I remember (it was a long time ago) is based on the Phi (golden mean) ratio.
The altitude of each side is phi (1.618) times half the base, and the central altitude is square root phi times half the base. That makes the angle between the sides and the base 51.827 degrees.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 12/17/2008 9:53 pm ET by Riversong
Edited 12/17/2008 9:53 pm ET by Riversong
Good to see ya back and posting.
Hey, did Fibbinacci come along before or after the Egyptians? I mean did they know it first and and he just linked it to nature or what?
IMWTKSpheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
"Hey, did Fibbinacci come along before or after the Egyptians?"
Hey Sphere -- last I checked, the Egyptians were still around, unless you know sumpin I don't. ;-)
FWIW: The Fibonacci numbers first appeared, under the name mâtrâmeru (mountain of cadence), in the work of the Sanskrit grammarian Pingala (Chandah-shâstra, the Art of Prosody, 450 or 200 BC). (Wikipedia)
Mike HennessyPittsburgh, PA
"last I checked, the Egyptians were still around"
So's Fibonacci. He's sleeping in his pyramid and he's still sharp as a blade.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes