Formula is (h^2 + w^2)/(2h), where h is the desired height of the arch, w is half the width of the opening. Algebra is much cleaner. Thanks for sharing.
very useful video sir ihave ever seen at site frequently face this problem that how can we find arch radius without auto cad at site and you solved my problem brother thanks alot for making this informative video
Great video Greg, Here is another way of doing the calculations that does not involve squaring two numbers or needing to write down numbers to then use them later in the calculation. Here it is R = Dw² ÷ (8×Jp) + Jp÷2 where Dw is the door width; Jp is the jamb intersect point (or height of the arch); and of course R is the radius you’re looking to calculate. In your first example Dw=36”; Jp=12” therefore R= 19.5”. In the calculator just type 36 x² ÷ 8 ÷ 12 = + 12 ÷ 2 = {x² is a function key, it appears on most calculator apps by turning your cell phone horizontal} try it love ur videos -Eddie
In example 2 you calculated 36 + 600.25 = 636.25 which is correct then under 6 times 2 = 12 you annotated 12 / 468 = 53.02 (468 from example 1). I now know the calculation should be 636.25 / 12 = 53.02. Just learning this stuff and it threw me for a loop.
You're right and it looks like I carried that number over from example #1. It looks like you're the first to find it or at least the first to mention it.
I have a question. What not just use basic geometric principles without numbers, i.e. without calculations? I mean, what is the benefit of doing it this way? I though a master carpenter, or at least a master in the classical approach I guess, would use nothing more than a compass and straight edge (and perhaps a ruler only for determining height and width of the wall) if he were drawing it on a plan. Even easier on a computer, just add the circle and let the computer spit out the final measurements. Recently I’ve been doing no-math geometry and could easily create those arcs with no calculations. If the height and width are given, I could do a scaled down version (just reducing ratios like a triangle [architecture/engineering] ruler does). The only number I might need is the amount to subtract from the center to achieve the desired result (e.g. -3” from center). And I am doing this with pencil and paper. There might be a learning curve doing it on a computer, but once the principles and methods are known, it would be even quicker and more accurate. Even taking your time on paper there is a slight imperfection, even only microscopic. But nothing is truly perfect except on paper anyhow, so to speak.
The benefit of using math formulas usually provides you with a faster and more accurate design. As far as master carpenters go, I think I would need you to provide me with your definition of one, before answering your question. There are definitely other ways to design arches like these and you're right, most of the time they don't need to be perfect, just close enough.
I only use them to provide viewers with additional examples in hopes of making a little more sense out of the information, but as James suggested, the designers will usually provide you with all of the measurements.
It's a random number used to create a desired look and can be 6, 12 or 20 inches. Some designers have a specific number they use for aligning two or more arches up in a wall and would need to use the same number.
Also, isn’t the radius simply half of the opening (assuming squared opening like any regular door/window would be)? Just measure the opening edges and divide in half. No simplification of fancy formulas needed. It doesn’t get any simpler.
Yes, the radius is half of the diameter and the diameter is the full width of the circle. If you're going to create an arch shaped like half of a circle, then the radius would be in the center of the opening. Let me know if that doesn't make sense.
If you could correct your formula would make a lot more sense. Your number divisions are back to front. 24 divided by 468 certainly isn’t 19.5, but 468 divided by 24 is.😁
There is a mistake in example #2 - where 468 should be 636.025 and thank you Apophis.
Formula is (h^2 + w^2)/(2h), where h is the desired height of the arch, w is half the width of the opening. Algebra is much cleaner. Thanks for sharing.
Algebra definitely looks cleaner to those who understand it. Thanks for posting the formula.
(h^2 + (w/2)^2) / (2h) is what you mean I believe.
@@lancastermick w is defined as 1/2 width of opening in my example. defining w as simply the width then your formula works, and is more comprehensive
very useful video sir ihave ever seen
at site frequently face this problem that how can we find arch radius without auto cad at site and you solved my problem brother
thanks alot for making this informative video
I'm glad it helped.
Thank you. Big long arch exactly 14 inchesx 14ft to work on tomorrow. It's a casing arch over a window using maple hardwood
Great information. Knew it was out there somewhere. Just hadn't stumbled across it until today. Thx!
Glad it was helpful!
Great video Greg, Here is another way of doing the calculations that does not involve squaring two numbers or needing to write down numbers to then use them later in the calculation. Here it is R = Dw² ÷ (8×Jp) + Jp÷2 where Dw is the door width; Jp is the jamb intersect point (or height of the arch); and of course R is the radius you’re looking to calculate. In your first example Dw=36”; Jp=12” therefore R= 19.5”. In the calculator just type 36 x² ÷ 8 ÷ 12 = + 12 ÷ 2 = {x² is a function key, it appears on most calculator apps by turning your cell phone horizontal} try it love ur videos -Eddie
Sounds good and as always, use whatever works best and what is easiest to understand.
Where does the eight in (8xJp) come from?
Excellent
Thank you so much 😀
I think it should be " 12 divided into 468" or you could say 468 divided by 12
I will try to remember that and thanks for the information.
Great help, thanks.
You're welcome!
Thank you
You're welcome
Beautiful
Thank you
In example 2 you calculated 36 + 600.25 = 636.25 which is correct then under 6 times 2 = 12 you annotated 12 / 468 = 53.02 (468 from example 1). I now know the calculation should be 636.25 / 12 = 53.02. Just learning this stuff and it threw me for a loop.
You're right and it looks like I carried that number over from example #1. It looks like you're the first to find it or at least the first to mention it.
I have a question. What not just use basic geometric principles without numbers, i.e. without calculations? I mean, what is the benefit of doing it this way?
I though a master carpenter, or at least a master in the classical approach I guess, would use nothing more than a compass and straight edge (and perhaps a ruler only for determining height and width of the wall) if he were drawing it on a plan. Even easier on a computer, just add the circle and let the computer spit out the final measurements.
Recently I’ve been doing no-math geometry and could easily create those arcs with no calculations. If the height and width are given, I could do a scaled down version (just reducing ratios like a triangle [architecture/engineering] ruler does). The only number I might need is the amount to subtract from the center to achieve the desired result (e.g. -3” from center). And I am doing this with pencil and paper.
There might be a learning curve doing it on a computer, but once the principles and methods are known, it would be even quicker and more accurate. Even taking your time on paper there is a slight imperfection, even only microscopic. But nothing is truly perfect except on paper anyhow, so to speak.
The benefit of using math formulas usually provides you with a faster and more accurate design. As far as master carpenters go, I think I would need you to provide me with your definition of one, before answering your question. There are definitely other ways to design arches like these and you're right, most of the time they don't need to be perfect, just close enough.
I noticed in each example, you used different height. What determines the height? Is it builder preference or is it based on opening?
Builder preference mostly
I only use them to provide viewers with additional examples in hopes of making a little more sense out of the information, but as James suggested, the designers will usually provide you with all of the measurements.
in the third example, how did you arrive at 14" ?
It's a random number used to create a desired look and can be 6, 12 or 20 inches. Some designers have a specific number they use for aligning two or more arches up in a wall and would need to use the same number.
Height times 2 is really; 2 times the height.
Yes
Also, isn’t the radius simply half of the opening (assuming squared opening like any regular door/window would be)?
Just measure the opening edges and divide in half. No simplification of fancy formulas needed. It doesn’t get any simpler.
Yes, the radius is half of the diameter and the diameter is the full width of the circle. If you're going to create an arch shaped like half of a circle, then the radius would be in the center of the opening. Let me know if that doesn't make sense.
If you could correct your formula would make a lot more sense. Your number divisions are back to front. 24 divided by 468 certainly isn’t 19.5, but 468 divided by 24 is.😁
Yes, I think most viewers get it, but it would have been better if I showed the process with a calculator. I might pull the video and remake it.