In preparation for ultimately building a far
more complicated FLLW 'Origami' (Butterfly) Chair,
I thought I would try a simpler piece for 'practice'.
The Yemassee Side Chair, shown below from a 1982 exhibit at the Metropolitan, is almost completely rectilinear. No compound angles. The sides, while they appear to have a slight splay - could also be left parallel - eliminating any back support bevels.
Plus its a nice looking chair.
While I was unable to find actual drawings for this chair, there are numerous photos available of similar chairs - such as the Eiffler chairs at Seth Peterson. To me the key dimension was the angle of the seat. The seat angle of the Peterson chairs measures 11 degrees. I believe the same angle is used in at least one version of the Origami chair, but in that the back does not appear perpendicular to the seat. There is a slight backward tilt.
I decided, for this 'practice chair' to base everything around a 12 degree seat tilt, with the back perpendicular to it.
Following is some info on the chair I built. As always, this information is 'as is where is'. No 'guarantee of fitness for purpose', that it won't fall apart tomorrow, that it will be comfortable etc. etc. But use the info anyway you wish.
Before constructing anything, I usually make a rough sketch and cut sheet - the following PDF is that:
You can see why I got a 'D' many years ago in 'Engineering Drawings' at RPI. Here summarized is the text for the Side View sketch:
1. From 4 x 8 3/4 A/C 'lumberyard' $30
plywood, cut two pieces precisely 30 inches square. (sides) (I tacked two pieces
together with A sides inside and cut both pieces at the same time)
2. Cut two pieces precisely 22 x 26 (seat and back)
3. Take tacked-together side pair, mark bottom edge at 10 1/2 inches from left,
and 3 inches from right
4. Put a point 12 3/8 inches vertically up from the 10 1/2 inch mark
5. Mark right edge 16 1/2 inches up
6. Connect Point 4 to the right edge 16 1/2 inch mark
7. Draw line perpendicular at Point 4 to the line just drawn in 6 - off top edge
8. Draw line from the top intersection of Line 7 to the bottom left corner
As Built Change: I rotated (moved) line 8 2" to the left to give more meat in the back support - and to not bring it to a sharp point
9. Draw line from 3" in from right
bottom to 12" up from right side edge.
10. Using square, 'square off' front of seat drawing a line perpendicular to
the front edge of the seat, moving in about 1" so the drawn line is
about 4 1/2" where it intersects line 9. (This
is where front stretcher will be placed flush)
As Built Change: To make the chair sit better on a non-level floor, I cut a small relief on the bottom sides. Mark bottom about 4" in from left, and again about 4" from right. On the left mark, place a mark 1/2 inch up. Draw 1/2 " vertical line. Connect the endpoint to the right bottom point 4" in.
Breaking down a 4 x 8 sheet by myself, and making the cuts needed for the sides, is something I would not even have attempted without my Festool TS-55 Plunge saw.
Both for precision and safety, I found this tool, with its aluminum guide, to be indispensable.
If you are comfortable doing so, you might be able to use a good worm-drive circular saw with a fence. But for me doing so never seems to give me a straight edge, and more than once I've experienced binding and/or kickback.
With the TS-55, you glide comfortably through both 3/4 inch pieces simultaneously. And you will not believe the edges you get - until you see them. Even with the standard blade. The saw is really worth its exorbitant $400+ price.
Here is the setup I used:
The 3/4 sheet of A/C sits on top of a 'sacrificial' sheet of 5/8 CDX. You will slice this up a little as you make the through cuts on the A/C. Set the Festool for a 27 mm plunge depth for a single sheet, and 47 mm for cutting two sheets together.
Clamp Everything! Clamp the plywood together with the CDX, clamp the guide rail at both ends to the underlying A/C and CDX as well. I NEVER rely on 'carpet tape' or a 'router mat' etc. Here the nearest hospital is 40 miles away.
Above 2 pcs of rough cut 32 x 32 are about to be flipped over so inside is to inside - they will then be tacked together with 1 1/4" brads mostly in off cut areas.
Flipped and tacked. You might have two good square TS-55 cut sides at the point that you can match up as I did with fence here.. Then you only have two 47mm cuts to end up with 30 x 30. But if they don't match, just recut.
Getting set to make one of the two 30 x 30 finish cuts. The plywood was NOT cut square from the lumberyard.
Above is the cut you get with the TS-55 through two thicknesses of 3/4 ply They are SMOOTH... and completely chip-out free.
Above - Side is marked per sketch and ready to cut
Ready for cut D on front
Completing stopped cut for rear of seat. Remember the end of the cut will be an arc - not square. It would have been a lot easier to use a plain manual ripsaw following the TS55 kerf rather the jigsaw with its narrow blade needing a fence. I hate jigsaws.
Above - dry fit. With $15 WALMART cushion. The seat will be trimmed down later to fit.
Above - now we are getting ready to drill Kreg pocket holes on the C sides for the seat, back, and stretcher. I only have a mini-kreg here in the Adirondacks, so I clamp it with a 1" thick length of maple strip. Its at an angle - so clamp it TIGHT - or it will 'walk' as you start to drill. DO NOT attempt to hold the mini-kreg by hand! Clamp it!
Above - getting ready for gluing and final assembly of right side to the Back. The 1" maple strip is used this time as a fence to keep the side square to the back. (After the strip is itself clamped to the Back). Wax paper is between the maple strip and the side to keep glue off the strip. I put Titebond III on the back and side edge, then clamp as shown, then drive home pocket screws. Immediately unclamp and clean up. The screws provide clamping force.
The inner edge of the sides is about 2" from the edge of the back.
Above - opposite side of right side clamp up.
Process is repeated for the left side.
You now should have the two sides and the back be able to sit level on your table.
Same from another angle
Cutting seat to fit before gluing/fastening. Front edge is flush with the front edge of the stretcher
Chair completely assembled with seat and front stretcher.
You can't see the pocket screw holes underneath, but the ones on the back are pretty ugly. You could plug them, but since I had plenty of leftover ply I simply covered them with two glued ply cleats:
The cleats are about 2" wide and end at the chair bottom. I think they look better than the holes. Plus they should add a little more rack resistance. Also, since I may use the chair outside, the cleats are likely to survive better than plugs anyway.
That's it for now. Next I have to decide how I will finish it. I may just paint it, regardless of what FLLW thinks about that. But the wood doesn't seem to look that bad. Probably a varnish. Several sprayed thin coats.
Before that, I may put a coat of System 3 Marine epoxy coating on the bottom edge and couple inches of the bottom sides for rot resistance. The product is: 'Silvertip Laminating Resin' - I've used it on plywood boat transoms. After it cures, you overcoat with Marine Varnish for UV resistance..
Finally, some kind of treatment to help prevent the outside veneer splintering near the floor that we see on a lot of these chairs after they are dragged around. I have a bunch of small 2" brass hinges. Rather than use as a hinge, I might just fasten one plate to the bottom edge and the other to the inside side.
Any and all comments and suggestions appreciated! Suggest making them at the Save Wright BB, this thread:
http://savewright.org/wright_chat/viewtopic.php?t=2791
Regards,
Chris
6/12/2008 - Now that everything is cured, I finally had a chance to try it out with the WALMART cushion. I am almost 6' 2" - and the height, seat depth, and angle seem comfortable to me. I will go with 12 degree seat angle and likely similar seat heights on my Origami. If anything, the seat back, for a lounge chair, could use a bit of backward slope. You do sit pretty much upright. But as a side chair, porch chair, lawn 'party' chair - I think its OK.
I was concerned that the back of the seat - at only 12 3/8" off the ground - would be too low, making it difficult to get out of. It isn't. With the added cushion height and the 3/4" of the seat ply - it seems fine
Since its not going into the scrapwood pile and might be used outside, I did go ahead and coat the bottom edge and sides up about 1.5" with the System 3 'Silvertip Laminating Resin'. The stuff is horribly expensive, but you don't need much of it.
System 3 offers a 'Trial Kit' of stuff for $29. It includes enough laminating resin to probably do 3 or 4 chairs. Plus you get a $20 coupon to use on a 'real' order - should you to later buy a larger size - or something else.
Here is the link to the trial kit:
https://www.ndic.com/systemthree/trial_kits.asp
What I coated shown below:
6/13/2008
Well, a word of caution on the Silvertip Epoxy. While it soaks in, and seems to make the bottom edge as hard as a rock, it also soaks in under the masking tape. Even though the outsides are sanded to 220. So when you pull back the tape, you are going to see an irregular edge, as below:.
Prior to this I've only used the Silvertip to cover an entire piece - like a transom. This was the first time I've masked it off.
I guess I could have tried to seal the surface first - but part of the idea was for the epoxy to soak in. That it did. Probably enough that I won't bother with the bottom edge 'hinge treatment' mentioned above.
You can see I'm getting ready to spray it. Since its going on either the porch or outside, I didn't want to use anything with linseed oil in it - like Danish Oil - because of mildew. Likewise, I really wasn't enthused about a thick film that would start to peel in a bit.
So I decided to use a 'wiping varnish soak it in' approach. Marine Varnish cut 50-50 with mineral spirits, sprayed on and left to soak in. Not wiped.
After a couple spray coats the epoxy line is not quite as visible. No 'thick film' yet. I'll likely do a couple more light coats - until I start to get a light film.
6/14/2008
The top of the Walmart cushion had a loop in back. Convenient to put a 'Boat Cover Snap' thru to secure on back rear. Seat is kept sliding around by velcro:
Chair done. On porch (cushion off center. Not velcroed yet :>):
9/10/2008 Update
The chair has been on our camp porch now for almost 3 months. While people sitting in it say its comfortable - it gets little use. They prefer our conventional Adirondack Chairs - with arms for their drinks and snacks.
So - though it may look like h--- - I 'pasted' on some arms. Details here
Wife now claims it as her own :>)
4/16/2009 - "What I would do differently..."
I hope to be back in the Adirondacks in a couple weeks. Thinking I might build a set of three similar that can be placed side-by-side to replace a falling-apart junk quality sofa.
If I do, even though the Yemassee chair has the veneer grain running vertically, I'll run the fir plywood grain horizontal this time. Should make it appear lower and 'less of a throne'.
While I'll keep the pocket-screws on the underside where they really can't be seen - they sure are ugly in the rear of the back. Yet the way the sides rise up the back, and are tied to it, provides much of the chair's strength and rack-resistance. I may just compromise with narrower less-intrusive cleats to cover them again - maybe 1/4 in stuff. Possibly I'll switch to biscuits there.
I will buy the cushions before I finalize the dimensions. Here in FL we have 'Pottery Barn' which has racks and racks of cushions - no such store in Adirondacks. Maybe buy them in FL
I may keep the 12-degree seat angle, or possibly reduce it to 5 degrees or so for the 'sofa' use. But I will keep the seat back at the current 12 degrees off vertical. (Back 97 degrees to seat if I go with seat at 5 degrees slope)
Questions or suggestions always appreciated! You can email me at: chris 'at' aii.com, replacing 'at' with @.