Arch calculation for layout (find radius, given span and depth of arch)

[@abewilcox4560]

You are the best math teacher I've ever seen.

[@whatworkedforme]

great information.. in the end i created a simple spreadsheet (use it on my phone) and all I have to do is put the width or total width of the arch and desired height of the arch.. calculation done for me, instantly, based on your figures. simples. Thanks again

[@apprenticemath]

That's a great idea!

[@simpleman283]

I had the second formula. I'll play around with comparing the two to see witch one I like the most. I never learned metric here in USA but I know my inch fractions, at 15:55 you said good luck with 0.3 of an inch, all you have to do 0.3 X 16 = 4.8 sixteenths. We were supposed to go metric 45 years ago but never made it. Any helpful video gets a 👍 from me.

[@RgarciaTube]

Thanks a bunch, I have been attempting to arch a 10 foot open with a 12 inch arch for a fence project, this is will definitely solve my problem.

[@benwilliams1172]

god this guy made this complicated. to find centre of any length , measure from one side further than what you think is centre and mark. do the same on other side of opening and mark. measure distance between marks and half it . that's centre now you have the centre open compass to the desired height and draw a half circle. from the side draw a line down at 90 degrees to the base line. open up the compass from one side of the opening to the other . transfer distance to line marked 90 degrees off the base and mark on the line open up compass from mark to opening on the other side and strike a arc to where it meets small half circle . do same on other side and you have a arch.

[@udayank.r2504]

Sir I watched lot of video's but this video very useful thank you so much

[@shaunmitchell5213]

Thank you for posting this video, I have been struggling with this all morning, you explained it in a way that I can fully understand. Thanks again Mitch

[@apprenticemath]

+Shaun Mitchell Thanks for watching & commenting.

[@dustystahn3855]

Here is a simpler no math way. Think of a Gothic Arch as an A Frame building with curved rafters. Draw a line the length of the rafter on a floor or big enough work table and mark the center. Drive a nail at each end of the line. Place a batten against the nails and from the center push out the batten until you reach the desired curve. draw the curve on the inside of the batten and you have the inside of the arch. It is so simple any one can do it. Securely fasten blocks about two feet apart along the line and you have a building jig. The block spacing varies with the size of the arch. This method works for any arch from windows, doors to buildings. I have even used it to build boats. If you want a different curve, push the batten out at different points. It is fun to see how many shapes you can make.

[@bravo3541]

Your Formulas are great , but I got confused as to where the new number (R-radius begins and ends) on the drawing; at the span line or the top of the arch depth. Video is a saver.

[@sofiamahajan6717]

This is really helpfull.... Thankyou for this video

[@apprenticemath]

Glad it was helpful!

[@thalesnemo2841]

Graphically connect the top of the arch with the shoulder then bisect that line segment . Then draw perpendicular bisector and draw a line towards the central line that is the center of the correct circle.

[@apprenticemath]

It works, of course. The difference between doing math vs. geometric construction is that a geometric layout produces work that can be out by 10 mm on this scale. Math is accurate to several decimal places.

[@abscomm]

Human errors can be made in the measurements of your mathematical solution, so no option is better than the other as far as accuracy is concerned.

[@das250250]

Thales Nemo maths = speed and accuracy , the incredible language of math and geometry axioms

[@chadburke852]

The Kaveman Not in the building trades.

[@danprice7504]

Thank you! This video has helped me very much. Very simple and straight forward. Awesome!!

[@padraigharrison6919]

Do the formulas work for all different arch types? what arch is this?

[@E-E.ADVENTUREGEARS]

IS IT POSSIBLE IF YOU MAKE A PDF VERSION OF ALL THE REQUIRED MATHS FOR APPRENTICES

[@padraigharrison6919]

Is 637.5 the location of the striking point for a semicircle arch

[@robp1245]

Brilliant! Thanks, just what I was looking for, good explanation.

[@padraigharrison6919]

Do these formulas work with other arches. Or are they just for segmental arch

[@muppetbrother]

Clear as mud.

[@ryanb1874]

How to do it just using trig, need to know how to calculate where the center would be in any situation

[@kotteeswarankotteeswaran5007]

How to find area for semi circular conical arch kindly tell me

[@UmAr-ft6ze]

Sir by this we found radius now how to find curve length

[@chiller19100]

Great explanation. Thanks

[@atubeviewer4942]

Why was the left tape measure, on the corner at the 120 cm? Where did 120 come from?

[@apprenticemath]

Just a number that fit the sheet of paper

[@tomryan9616]

The standard formula for finding the radius of an arch is. 1/2 Span squared ,divided by Rise, plus Rise, divided by 2.

[@LiaqatAli-fk4mx]

yours formula is totally wrong dear friend

[@giovannitidona658]

In trade school we were taught to first find the center by overlapping 2 circles with protractor where the 2 circles meet draw a line through give you a long straight center line

[@piee683]

Thx for this..this solution has been bugging me 4 a while

[@nramos137]

Nice, does this work in inches as well?

[@apprenticemath]

Oh yes, same way

[@selvamlakshmanan8170]

thank you very much

[@kimmimaxwell7826]

I have a 13 foot opening with a 38 inch rise .. whats my swing ? thanks

[@apprenticemath]

You do the work

[@oilcanshawn4918]

99.05 inches if I learned this right

[@bradwatts8222]

a is half the chord , b is half the chord , c is the rise measured at the centre of the chord ........a x b divided by c = d ......d + c divided by 2 = radius , simple in mm , if your using inches god help you or just buy a metric tape measure 🇦🇺 straya 👍🏻

[@apprenticemath]

Works either way, units can be alien feet or Martian's hands, same logic works.

[@artistpw]

For an excel formula it is "=SUM((A1^2 + A2^2)/(A1 * 2))"where a1 is the arch height and a2 is half the opening distance

[@masterwelder65]

Great.

[@civilengineeringepu9263]

Good

[@petercrossley1069]

Just show how to derive the simple formula for the radius. Far quicker.

[@user-sj1tt3ie3z]

A squared + (B divided by 2) squared ----- then ----- divided by (A multiplied by 2) = answer. You didn't show to divide B by 2 in your equation at 10:00.

[@apprenticemath]

Right, not shown as at 9:13 I say "half the opening", then that number (510) is written down. b = half the opening, ergo the full opening is 1020, shown full scale at 5:28.

[@rauldeleon6524]

You don't use feet and inches

[@harrygirgin9093]

Ohh my God. Seriously I am lost.🙄🙄

[@brianjames5343]

Why is Jean claude van dan doing a Arch .

[@apprenticemath]

Fun, eh?

[@isaacrobles1764]

sorry there r 2 diferent easy ways to do it

[@richardbailey2001]

Why didn't you give people the formula for finding the arc .. It's pretty difficult to use these ideas in the real world without math ....

[@apprenticemath]

Formulas clearly given at 9:03

[@MrTjp420]

where are you from lol 20 inches that is 25.4mm bloody hell my work sent me to trade school and i feel they are gearing me up to build rockets.............

[@oilcanshawn4918]

I just wish you used inches

[@philquinn73]

Two thumbs up!!

[@davidburns1753]

I cannot find anyone to help me solve what I think must be simple for smarter people that me. I am just barely smart enough to look for answers. Let me try to ask my question without the benefit of pen and paper. Imagine that you know the width (chord) of an arc and you know amount of rise or deflection you want to achieve over that length ... let's say one foot. Is there no way to make a measurement, or many of them over the length of the chord to measured points along that chord thus defining the desired arc? If This makes no sense, forgive me. I can see clearly in my own mind what I am asking, however, that does not mean that others can understand what I want to know. If anyone can help, it will be much appreciated. Likely the answer is simple and I should know it, but guess what ... I don't. One more item ... you may wonder why I do not get a string, a nail and a pencil and do a trial and error method ... that would work, but not with the amount of space available in this and in many circumstances which I come across. HELP!!! PLEASE!!!

[@apprenticemath]

Yes, an arc can be defined by different chords starting from the same point. To get to radius, the lengths of chords need to be known and the angles between them,

[@جمالالعبد-ف4ج]

جيد

[@zully756]

Ellipse

[@imranchohan9478]

Horrible way to explain

[@LiaqatAli-fk4mx]

tooooo bore

[@apprenticemath]

I'm not treating your attention deficit disorder or care to hear about it

[@JulioHernandez-gt5hs]

you talk to much keep it concise