Woodworking Angles Building A Chair - Geometry Tip (Part 1)

[@davidnickell9381]

If I had watched this before I started woodworking, I would have taken up stamp collecting. Now that I'm already committed, I'm glad I found this video.

[@DsHardWoodCreations]

Lol absolutely

[@studiohost]

😂

[@lana-hd1gs]

I LOVE these videos where you use geometry. I am a math teacher and assign your videos for homework in my geometry classes where students need to explain the theory behind what you are doing using definitions, postulates, and theorems. Thank you so much!

[@ChadStanton]

Thank you so much. I’m glad that kids can see practical applications to use math in the real world verses just a book example.

[@igtbtk8]

First of all, thank you for making this video. It’s fascinating to see how a craftsman would solve problems like this. I’m a math teacher. My solution to this problem involves three applications of trigonometry and a use of the Pythagorean theorem. Your elegant geometric construction of the required angle is really beautiful. I wonder where this originated. For anyone curious, the mathematical description of the resultant angle I wrote down was R(s,r) = arctan(sqrt(tan(s)^2+tan(r)^2)) where s is the splay angle and r is the rake angle. Not an easy formula to remember or even calculate reliably (you need a calculator for sure). In fact, even though I just finished deriving it, I still almost forgot the square root!

[@TheFincaAdventure]

Whoa very cool! Thank you! How about the Sight Line Angle?

[@Kunfucious577]

I love KZbin cause you can find an answer for anything you need. I’m having and issue with my chair angles and found this channel. Thanks

[@ChadStanton]

I'm so happy to hear that my video was able to help you.

[@texsox]

Chad, as an educator my hat is off to you. That is a great lesson. I can’t wait for part 2.

[@TimTurner115]

I never understood geometry. But in a way that makes a lot of sense. What I do not understand I will hand it to my wife she's the mathematician of the family. Thank you for the information I've always wondered about it. And it wasn't boring at all

[@dusannikolic8635]

great lesson Chad, thx for sharing the wisdom from old master craftsmen! rgds to Denis as well!

[@ChadStanton]

Thank you. Dennis is a world of knowledge. I am lucky to know him. So i try to pass on his knowledge to everyone

[@wb_finewoodworking]

Wow, Chad that’s awesome. Someday when I have time I’ll do as you suggested and work with this video and the subsequent videos and make a bench using your information. That’s something I’ve never attempted. Thanks.

[@saulpenilla778]

Thanks Chad for confusing me more, I mean for clearing that up. 😀 I'm looking forward to the video to rewatch this to hopefully understand it better. Roy Underhill has an episode that he explains it too.

[@shortliner68]

Great information! I also used this method to figure all four angles of the seat back posts or stiles on an antique style pedestal mounted school desk chair I want to re-create. I have the antique iron seat pedestal...just need to rebuild the missing wood seat. Thought it would be an interesting project.

[@chancebralley5613]

Chad I always enjoy the education videos. 👍

[@pdcro1247]

Exceptional video So well explained Should be used in trade schools

[@ChadStanton]

Thank you very much. I truly appreciate your comment.

[@scottlouis7785]

I remember some geometry after 65 or so yrs but i know i will need a refresher course if ever

[@andysims9184]

Great stuff. Looking forward to the next video

[@suzannewilliams1214]

Great video! Thank you for this information. Question: How did you decide where you wanted the hole placement to be? I'm looking to build a bar-stool height seat and want to make sure I get the right angles to avoid tipping.

[@timdoyon1964]

I always enjoy your videos Chad. Boy, you were right when you said we would need to watch this a few times to really grasp it, but I think I'll watch part 2 before I do so I understand how the angles will be applied. I've been a woodworker for a long time, but have yet to build a chair, because I don't know how to properly design one. There's also angles that the seat sits to the floor, and the back angles backwards from the seat. 😵‍💫 It's all so confusing!

[@ChadStanton]

Oh yes. A chair is the most complicated thing to design properly. I was told you have to build at least 12 chairs before you get a good idea of comfort and ease. I did a few other chair videos. They might help you.

[@timdoyon1964]

@@ChadStanton Thanks Chad, I’ll watch them right away!

[@Uncle_Buzz]

Chairs have always been a scary mystery to me. Good stuff Chad. Cheers & Merry Christmas! Chris.

[@dwightl5863]

Thing is now you know why it is a scary mystery, I think?

[@thomastittlemier2104]

ZZZZZ, What's that Mr Stanton, no I wasn't asleep. Will this be on the final exam? Ah High school. Great video Chad.

[@peterfitzpatrick7032]

Tom ... Just draw it on yer hand like I did !! 😂😂😂

[@poofypoopy8838]

Just built a dining room set that had plans by the time this video ended😉 But thanks all the same!

[@andoovellayan]

Boss, its cool. Thank you. Like to give it a try.

[@mr.gawronski9355]

What I need to know is where is that circle in relation to the stool?

[@DmitryKopytine]

Let's use some math guys :) Resultant angle = atan(sqrt(tan(splay)^2+tan(rake)^2)). Sight line angle = atan(tan(splay)/tan(rake)). This comes to resultant angle = 13.488, sight line angle = 54.132 with the initial splay=11 and rake=8. Just be sure that tangent and arctangent functions are calculated in degrees, not radians. Check that tan(45)=1 and atan(1)=45 to be sure that it's set up correctly. Sqrt function is a square root, ^2 is a second degree. IMO, it's much faster than the geometric or sketch up version (if you have a proper calc). See links below for results and replace 11 and 8 with your numbers.

[@ChadStanton]

Thank you for that. I was never good with remembering equations. But it's good to see another way of coming to the same results.

[@peterfitzpatrick7032]

What sort of witchcraft is this ?? 😓 GET THE HELL OUTTA HERE !! 😂😂😂

[@DmitryKopytine]

@@peterfitzpatrick7032 I'm just too lazy for drawing geometric interpretations :) And before this video I thought it's not accurate enough. But since Chad received so fenominally precise results, I no longer think that protractor is for approximate results only.

[@kishorekrishnan9085]

Nice. Very simple explanation

[@R2d2koko]

I m layman for woodworking , This is what I wanna know n learn , from the drawing i totally confused and do not understand 😅😅 thank you for yrs teaching

[@americooneight4361]

Sweet info thanks

[@discgolftrainnut]

That brought back high school memories (45 years ago).

[@jettkeyser9909]

A lot....Thank you

[@waynemorrison9905]

Now I know why I leave chairs up to my friends Chip and Dale. Still enjoy your stuff.

[@peterfitzpatrick7032]

Okay.... no chair-building for me... boxes only... & square ones at that !! (Well , maybe the odd hex one ) 😂 Thanks Chad !!

[@chancebralley5613]

Peter Fitzpatrick LOL rolling in the floor laughing. My dog came to check on me.

[@bradsoulchin5334]

QUESTION : When you said "the height of the chair didn't matter", is that for figuring out the 3rd and 4th angles because you already figured the splay and rake angles using the height of the chair and had those numbers to start the calculations for 3rd and 4th angles?

[@ChadStanton]

I said it didn't matter because i was just concerned with degrees. However if i scaled it (using the height) i could figure out the exact length of the leg.

[@bradsoulchin5334]

@@ChadStanton is this going to be part of the process? (Length of the leg) or is this only for the angles to drill the holes?

[@peterfitzpatrick7032]

Brad , when I started to read your comment.... I thought it was like...."Is this going to part of the test ? " ... 😂😂😂😂

[@bradsoulchin5334]

@@peterfitzpatrick7032 lol...I hope so. That would suck to get the hole right then have to make numerous attempts at the leg to get the chair the right height.

[@ga5743]

All I know about a chair is I like to sit on them.......this is way confusing to me. You are a smart guy Chad.

[@Gig81]

Here in Italy we call this kind of things "supercazzola"

[@byhammerandhand]

Seems like you are going off on a tangent. (tan=sin/cos)

[@sethbracken]

Keith Mealy lol you beat me to it.

[@cobberpete1]

And we thought Rocket Scientists were smart. You beat them hands down Chad :D

[@barronguy]

Anyone know an easier way to do this?

[@tedsobocienski787]

Good grief, my worst subject in high school was geometry. Now it's come back to haunt me.

[@mralabbad7]

This is waaaay more complicated than it needs to be

[@Terentii175]

Bad news for me, because, I can't visit your site. ( So please, Chad, don't delet all your videos about tips with geometry in youtube. Sorry for my English.

[@squareswing]

Screw this! I'm going to "eyeball" it, or make a folding chair, maybe a Viking chair.

[@kenkirkland1056]

OK I'm confused......Is anyone else out there understanding all of this ?????

[@ChadStanton]

I'd like to help you. Can you clarify at what point you got confused? Maybe i can clear it up for you.

[@peterfitzpatrick7032]

ALL of us.... except you Ken... 🙄😏😂😂😂😂

[@drochon6672]

Well, that was easy enough.....I think.

[@DsHardWoodCreations]

Man i wished id listened better in math class.

[@Honedfinefurnishings]

Ummm newbie here. You lost me at “let’s draw a chair”. Where is the chair? Back vs seat. I’ll watch the recommended few times. Then, watch it (3) more times. Maybe I’ll see it somewhere in the middle. I’ll find my angle of that middle relative to the beginning and end, and make a chair out of it. 🤣😳

[@diederichabels8119]

I prefer to build with Woodglut plans.

[@chrischurch4551]

So, you taught me not to make chairs.

[@mjlly1]

OK, I will never be any good at woodwork.

[@jessicasommy1741]

I prefer to build with Stodoys plans.

[@lestergrayson3049]

I'm glad you labeled all that I'm color blind

[@johno6861]

You have made it awfully complicated without even having attitude for the seating. A chair is not level and if you really want a good looking chair all the lines would be pulled off perspectively. We use to do this without computers. Yankee workshop shows you how to do this in 15 min without confusing you.

[@ChadStanton]

It's not complicated to me. Level of the chair is not just splay and rake but also the length of the leg. I do not use a computer i use a compass and protector. I can do it under 15 minutes. (11:14 to be exact) So i guess that takes care of your issues.

[@johno6861]

Yankee does it without paper, geometry or power tools .

[@ChadStanton]

@@johno6861 Now that is amazing. Ill have to check it out. Thanks for the suggestion