Chairmaking Question

[Howard gorm]

I am making chairs for a kitchen set and by looking at other chairs it looks like the angle of the back leg that rises above the seat is 102 degrees. I know this can vary so I'm looking for an average angle, appreciate comments on this. Thanks

[Gary Ragatz]

Stuff I've read on chair ergonomics suggests 95* - 105*, so it sounds like your 102* is on target. Personally, I don't like a dining chair with a back that's too close to vertical.

[Tony Leonard]

I can't give you an average, but ironically, I am building a set of chairs for our breakfast room. Just finished gluing up the backs and fronts today (assemblies). I measured every chair in our house when I was working on my design. My chairs have no straight lines (almost), but the back angle comes out to ~98° (its a curve). Its really a personal preference thing. We have chairs we know are comfortable to us, so I stayed close to those dimensions. My prototype chair sits pretty comfortable for us, but we are short, so they may not feel good for others? I built a prototype out of poplar to figure out dimensions and how to make all the various parts.

These things have been the biggest woodworking challenge I have ever taken on. I made them more complicated because I didn't want straight backs (my backs are compound angles). Oh well. I do like the look. Just hope I can pull it off. Mine are cherry. I'll be working on assembling the fronts to the backs this week. More angles!

Tony

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[Thomas McCurnin]

According to a posting in the old Fine Woodworking Blog, the most common among all was 105 degrees from the seat top to the back. https://www.finewoodworking.com/forum/standard-angle-for-back-of-dining-chairs

(https://www.finewoodworking.com/forum/standard-angle-for-back-of-dining-chairs)According to Kevin Rodel's plans for a Craftsman Dining Chair, Fine Woodworking April 2007, the angle is 7 degrees.

According to Tom McLaughlin's article in Fine Woodworking in June 2020, there is no stated angle, but an offset or splay of 3 1/2" whatever that equates to in degrees, and he did a slightly different chair for May 2011 for Wood Magazine and the offset was 3 inches.

According to Paul Kemner, Building Craftsman Furniture (Rodel Press 1997) there is no stated angle, but the offset is 3" and this is from The Craftsman magazine from the 1920s, I think a Number 306. Note that Stickley made the rear of the dining room chair lower than the front, so you butt sinks lower into the chair, and that angle is slightly less than 2 degrees, I think Kemner stated it was 1.75 degrees, which really complicates the rear leg joinery. But with full size plans or a templates and a custom bevel square, it is doable.

According to Wood Magazine staff, the back angle is about 5 degrees. https://www.woodmagazine.com/must-have-measurements-for-comfortable-seating

(https://www.woodmagazine.com/must-have-measurements-for-comfortable-seating)According to Paul Sellers, for the Sellers Craftsman Chair that I built in April, again, we did not use angles set in degrees, but numerical inches in splay. So from the top of the seat rail to the top of the chair, it was 3 3/4" inches difference, whatever that equates to in degrees. The plans for this Sellers chair can be found in Wood magazine December 2004 or in his Master Class blog which is not free. I just took that class a couple months ago, so I am fresh from chair building. I do recommend a good set of MDF templates. Some joints are honestly easier made by hand, and others easier using power tools.

I have collected no less than 10-15 plans for chairs and can pass them along if you care to receive them by email. Let me know.

I do recommend Jeff Miller's chair book, Chairmaking & Design (Linden Press 1997)although when it was written in about 2004, he was fixated on router and router jigs (but now seems to have gone partially Neanderthal), and there are about six different jigs to build to build his dining room chairs, a chair postioning jig, a tenon jig, a mortise jig, a custom bevel square (to set compound angles), a rear leg flush trim jig, and others. If you are building a set, Jeff recommends that you build a plywood mock up and check it for comfort and to insure it fits under the table you are using.

[Alex Zeller]

I would start off by watching how people eat. The people who eat at my house don't use the back while eating. They lean forward slightly. Once done eating they lean back to relax. If the back is too close to 90 they will slide their butt forward to compensate. At 102 degrees their butt seemed like it wasn't close to the back of the chair. This lead to me concluding that the shape of the seat plays a role in the angle of the back. The chairs I was using to gauge had flat seats making easy for the butt to move to make the angle work. My plans were to make contoured seats until I realized that a lot of dining chairs avoid this as it makes moving the butt to adjust the comfort level harder. It's also why having a curved back is helpful. Those who want more angle will slide their butt forward and use the higher up, more of an angle back of the chair while those who like closer to 90 will keep their butt closer to the back. In the end I figured curved going from around 100 (at the first point someone will make contact with the back) to 105 looked like it would work. Now if I can get the wife to decide on what species wood she wants I'll start working on it.

[Mike Henderson]

I've built a number of chairs, both dining room chairs and rockers. You don't want the back to lean back too much on a dining room chair, but neither do you want it straight up. I'd have to check mine, but 100 degrees sounds about right.

Jeff Miller's book is good.

Mike

[Howard gorm]

Tom, thanks for such a full reply, would love to have the plans if it's not too much trouble my e-mail is woodcontours@gmail.com

[Howard gorm]

Thank you all for the advice I am going to do a poplar mock-up with a 102 degree angle for the back and see if that works.

[Randy Heinemann]

I am attaching a diagram which shows the standard specifications of chairs made by Michael Fortune. It was supplied as a resource from an online live Fine Woodworking demo/presentation by Michael Fortune. Given his chair experience I's assume that the measurements produce great chairs. The drawing shows that the seat is angled 5 degrees up from a line parallel to the floor and the seat back is angled an additional 103 - 108 degrees (total of 108 - 113 from the line parallel to the floor). The angle of the seat is important also as strictly parallel with the floor may not make a chair comfortable. Anyway, this is just another resource, but it is from an expert chair maker.

[Gary Ragatz]

I am attaching a diagram which shows the standard specifications of chairs made by Michael Fortune. It was supplied as a resource from an online live Fine Woodworking demo/presentation by Michael Fortune. Given his chair experience I's assume that the measurements produce great chairs. The drawing shows that the seat is angled 5 degrees up from a line parallel to the floor and the seat back is angled an additional 103 - 108 degrees (total of 108 - 113 from the line parallel to the floor). The angle of the seat is important also as strictly parallel with the floor may not make a chair comfortable. Anyway, this is just another resource, but it is from an expert chair maker.

If I'm reading the diagram correctly, that angle for the back is 108* - 113* from horizontal, not from the pitch of the seat. That would make the back 103* - 108* relative to the seat, which is pretty consistent with the numbers suggested throughout this thread.

I would imagine that a slight pitch on the seat is a good thing to help keep the diner's butt from sliding forward - if it's a solid wood seat. If the seat is going to be padded, I think you could make the seat parallel to the floor and the padding would accomplish the same thing.

[Bob Riefer]

For some unknown reason I decided to "design-on-the-fly" (as in no research, no drawings, nothing) a set of 5 chairs for the dining table in our sunroom. I wish I had added more 'tilt' to the backrest vs. the about 5 degrees that are present now. It's a bit more "upright" than I would like. To mitigate, I shortened the height of the backrest and will be contouring. It will be fine, but it was wise for you to think through it, and I will add a few more degrees next time around. From last night:

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[Phillip Mitchell]

I just built a set of 10 dining chairs (8 sides + 2 arm chairs) and found Jeff Miller’s “Chairmaking and Design” book to be of immeasurable assistance and important as a reference and confidence builder. I loosely based my design off of a mix of his chapter on the slat back chair as well as a couple of different chairs in my own house that looked and felt right to sit it.

As others have said, there is no magic number of seat back angle but instead a range that different people will find comfortable. I don’t know if I ever did the math of that particular angle (seat back compared to vertical or horizontal) but I’d say it’s in the 10* off vertical range. The angle along with the arched crest/back rails are very comfy and inviting to lean back and settle into. Very supportive.

With my seats, I built the frame flat/level/horizontal (no compound joinery from side rails into legs) and then shaped / scooped the seat itself to be about ~ 3/8” lower at the deepest part of the scoop for just a bit of backwards tilt in the seat itself as opposed to the entire chair seat frame. Feels very nice on the rear/legs.

This is my first real set of chairs, so take this with a grain of salt but Jeff Miller’s book is worth it’s weight in gold for a beginner / novice chair builder.

I’ll see if I can dig up some photos of both the chairs as well as some in process photos that may show the angle a little more clearly.

[Randy Heinemann]

Yup. I think that's what I said.

[Mike Henderson]

For some unknown reason I decided to "design-on-the-fly" (as in no research, no drawings, nothing) a set of 5 chairs for the dining table in our sunroom. I wish I had added more 'tilt' to the backrest vs. the about 5 degrees that are present now. It's a bit more "upright" than I would like. To mitigate, I shortened the height of the backrest and will be contouring. It will be fine, but it was wise for you to think through it, and I will add a few more degrees next time around. From last night:

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I like the way you put that seat portion together with dovetails. Good idea - and good work, they're very tight fitting.

Mike

[Thomas McCurnin]

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Living in a 122 year old home, we happen to like Craftsman-Mission-Stickley type chairs A really great resource is Paul Kemner's book on building Stickley furniture, including a large section on a single chair design that Stickley used for 3-4 chairs, a 306, which could be a slim dining room chair, modified with arms, or attached to a rocker. Its all the same chair, although some modifications have to be made for the arms and rocker ones. The book is Building Arts and Crafts Furniture by Paul Kemner and Peggy Zdilla. Here is a photo of the basic chair design. Its lightweight, graceful and very adaptable to a variety of designs, as proven by Stickley.

[Mike Henderson]

When you build your chairs, remember that chairs with arms may need to be a bit wider than the armless chairs.

Mike

[Howard gorm]

Ordered the book yesterday. Looks like I don't have permission to launch the images.

[Phillip Mitchell]

When you build your chairs, remember that chairs with arms may need to be a bit wider than the armless chairs.

Mike

This is an important point that is worth highlighting. With my recent set of dining chairs (including 2 arm chairs - posted photos on the previous page) I was able to make the standard size chair width at the rear work with some front legs that curved out quite a bit from the seat height up to the arms. It’s a comfortable sit and entry into the arm chair, but next time I may consider making the arm chairs 1-2” wider overall at the backs / crest rails than the side chairs to help accommodate a wider opening between the front legs a bit easier. Design goals also play into this decision, and I actually like the “curved open” look compared to more rectangular design in this chair, but that’s all up for debate and personal preference once you have moved beyond the simple function/comfort.

This variable kind of depends on the size of the person sitting in the chairs; I am 6’1” ~200 lbs, so not small but not huge and it fits me well like a slightly large glove. If you want the chairs to be a size large then wider overall is better but typical side chair width can be workable with some flared out front legs like this.

[Thomas McCurnin]

Yes, and Paul Kemner covers this as well for arm chairs, as well as making the legs a little shorter for a rocker, not too short, because a tenon is needed to attach them to mortises within each rocker.