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  1. #16
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    Quote Originally Posted by auscab View Post
    one thing I would recommend John, is to draw the chair you want to do full size , all true and square . I do them on a large board of the one straight edge at the bottom with a large square . One of the most important thing to draw is the plan view of the seat through the joints , specialy if the back of the chair is narrower than the front. Then the front and side elevation are transferred from that. All the templates and joint angles can then be taken off that to cut the wood . When I made these chairs, Going from the drawing to the real thing showed proportions that I didn't like, that I couldn't see in the drawing . If I did them a second time around they could have become 20% better than they came out, Proportionally . The third time around they may end up 95% right . And the last 5% you never get. In the old days they did cheap timber prototypes and that solved the 20% problem from the drawing. The chairs are standing on the full size plans that the client was happy for me to go ahead with.

    Rob
    Thanks Rob,

    Did the full size drawings on sheets of 3 mm MDF yesterday, made some small modifications and am happy with the look. Some of these will be cut out to make the templates.

    The plan is to make one chair first. If that needs some refinement, I'll make another ... until I am happy with it. Then the other seven will be made. As you suggested, for a new design, its a good idea to try to prototype and test the design before charging off into the final job.

    Need to decide how to upholster the seat. Still tossing up between steel coil/zig zag springs and elastic/rubber webbing and etc. The design I have selected (so far) does not have posts on the legs, nor does it have a vertical frame over the legs (as in your pics), the legs and the rails is all there is. This has a bearing on how the upholstery is attached. Any suggestions?

    I made a 900 X 900 mm coffee table recently as noted in these pics.
    IMG_2025.jpgShelly Mitch 4.jpg

    I like that table, and the current plan is to make a square eight-seater that is essentially a pumped-up version. Essentially, the coffee table is the prototype. Love the slipper feet ... pity they can't go on the chairs. Again, no posts on the legs and no vertical frame over the legs and rails.

    Cheerio!

    John

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  3. #17
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    Quote Originally Posted by John Samuel View Post
    Need to decide how to upholster the seat. Still tossing up between steel coil/zig zag springs and elastic/rubber webbing and etc. The design I have selected (so far) does not have posts on the legs, nor does it have a vertical frame over the legs (as in your pics), the legs and the rails is all there is. This has a bearing on how the upholstery is attached. Any suggestions?



    John
    Nice looking table John , She's shiny ! and looks good for it .

    I dont understand what no posts on the legs means John .

    The woodwork in the back is to be polished ? and no upholstery to fill in the hole ? just Upholstery in the seat ?
    I would be doing a drop in seat for that and make a seat frame and get the upholsterer to do mine .

    Rob

  4. #18
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    Well I sit corrected Rob. Thanks for the post!

    I'm not sure I like the style but I can see the chairs would be very stable
    and that the four cabs sort of work.

  5. #19
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    Quote Originally Posted by artme View Post
    Well I sit corrected Rob. Thanks for the post!

    I'm not sure I like the style but I can see the chairs would be very stable
    and that the four cabs sort of work.
    No worries about the post and I'm being corrected all the time as well artme .
    I just happen to be doing a bit of chair research this week because of a chair job, so have had my nose in the books .
    Ive been buying books on the subject[ Furniture] for 35 years so have a bit of a library happening .
    I couldn't be without it.
    A tax deduction as well

  6. #20
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    Quote Originally Posted by auscab View Post
    Nice looking table John , She's shiny ! and looks good for it .

    I dont understand what no posts on the legs means John .

    The woodwork in the back is to be polished ? and no upholstery to fill in the hole ? just Upholstery in the seat ?
    I would be doing a drop in seat for that and make a seat frame and get the upholsterer to do mine .

    Rob
    Rob,

    The post is the vertical extension from the leg to which rails can be attached. See pic. The legs on your chairs have posts, but mine do not. My chairs will use the same construction method as the coffee table posted earlier. I am trying to keep the lines of the chair smooth and always rounded ... no straight lines at all. The rails attach directly to the side of the leg rather than to the post, so the rails have the same curved profile as the top of the legs.

    At this stage the design calls for the back to be polished with no padded insert. Did some tests over the weekend. The plan was to have the chair only 820 mm high, instead of the more normal 900 mm, a bit like a Danish chair. My tests indicate that if the horizontal member of the back is 150 mm deep, that it supports the back of the person using the chair quite well, again, like a Danish chair. I have Royal assent for this design, given that LOML was one of the test subjects in my mock-up chair.

    I was hoping to have the padding extend over the tops of the rails and the inner corners of the legs, but remember I have never made a chair before. Also, my experience with upholsterers is that they are anything but cheap, and was thinking of doing it myself, but that depends on the final design. Current thinking is to make a drop-in frame that is a bit like the pic below.

    The purple line is either ziz zag springs or elastic. The light blue is foam. The red is fabric and the black is the rectangular drop-in frame.

    Any thoughts or ideas would be appreciated.

    Cheerio!

    John

    EDIT: Can anyone point me at a good upholstery supplier in Brisbane?
    Attached Images Attached Images

  7. #21
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    John, what are you doing about corner blocks to stabilize the corners?

    I repaired and refurbished a set of chairs Ana shipped over from Brazil.

    They had been badly repaired some years earlier with steel corner brackets - externally!!!

    I pulled them apart and had to do some minor repairs to the mortice and tenon joints ( seat rails to legs )
    but when it came to cutting new corner blocks I had a couple of problems: old and fairly brittle cranky grained
    timber and no two angles the same!! The back angles were different to the front angles anyway.

    What I did was to cut and glue as large a square section piece of pine as possible, several inches long, and glue and screw this to one rail. I did the same thing on the adjoining rail, butting it as close as possible the the first piece. I had to cater for the fact that the inside of the rails were not vertical. A pest of a job!!!

    I finished of with triangles of ply glued and tacked top and bottom to the pine pieces.This gave a very strong and stable bracing for the corners.

    I don't expect you to have that problem with new joinery but it might be worth a thought to get all angles correct and not to have a sloping inside to your rails. It will save you a lot of hassles!!

  8. #22
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    Quote Originally Posted by John Samuel View Post
    Most chairs are about 900 mm high, but I think I'll keep mine to about 800 mm high, a bit like a Danish chair.
    I may have more time to comment later, but for now please be aware that there is a simple (and at the same time complex) relationship between the seat height of a chair and a table's top and apron.

    if a seat is too high your legs won't comfortably fit under the table

    if the seat is too low using the table -- in your case eating your dinner -- is uncomfortable.

    Joints
    I agree with Alex, floating tenons
    regards from Alberta, Canada

    ian

  9. #23
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    Hi, I'm sorry if this has been mentioned but is there any way of having the back and the back legs one solid piece as in more simple chair designs, or will this make everything too complicated?
    Kiwi.

  10. #24
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    Quote Originally Posted by artme View Post
    John, what are you doing about corner blocks to stabilize the corners?

    I repaired and refurbished a set of chairs Ana shipped over from Brazil.

    They had been badly repaired some years earlier with steel corner brackets - externally!!!

    I pulled them apart and had to do some minor repairs to the mortice and tenon joints ( seat rails to legs )
    but when it came to cutting new corner blocks I had a couple of problems: old and fairly brittle cranky grained
    timber and no two angles the same!! The back angles were different to the front angles anyway.

    What I did was to cut and glue as large a square section piece of pine as possible, several inches long, and glue and screw this to one rail. I did the same thing on the adjoining rail, butting it as close as possible the the first piece. I had to cater for the fact that the inside of the rails were not vertical. A pest of a job!!!

    I finished of with triangles of ply glued and tacked top and bottom to the pine pieces.This gave a very strong and stable bracing for the corners.

    I don't expect you to have that problem with new joinery but it might be worth a thought to get all angles correct and not to have a sloping inside to your rails. It will save you a lot of hassles!!
    Part of the plan is to block the corners ... and this may complicate the upholstery. Blocking the corners will be relatively easy because the design avoids the angles you mention. Some years ago I did a test for a table design using off-cuts. Two 30 X 90 mm rails were double biscuited to a 90 X 90 leg. Then the corner was blocked as noted below with timber pieces that were the full height of the rails. The black triangles were glued and screwed. So was the yellow brace, which was also dowelled into the rails and leg (dowels in white). I destroyed the timber trying to get the joint to fail. Eventually, I split the brace and the timber at the top of the leg, but the joint held. Says something about blocking corners.

    Corner of table blocked.jpg

    This time, tenons will be used, but it seems wise to block the corners, with particular reference to the rear legs. Next pic is sketch of new table.

    New Table.jpg

    Have fun!

    John

  11. #25
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    Quote Originally Posted by Kiwi75 View Post
    Hi, I'm sorry if this has been mentioned but is there any way of having the back and the back legs one solid piece as in more simple chair designs, or will this make everything too complicated?
    Kiwi.
    Kiwi,

    I fiddled with designs that made the sides of the back and the leg one piece of timber, but did not like the lines that this produced. So, it's a "looks" thing.

    The current design has the back fastened to the rear rail with a floating tenon that is 10 - 12 mm thick, about 450 mm long and which protrudes into both the back and the rail by 30 mm. This floating tenon also joins the bottom section of the back to the sides of the back. In this way, the sides and bottom of the back and the rear rail are all joined with the one tenon. I am confident of making a very good fit for the tenon, because all the mortices will be cut with a dado blade before assembly.

    If I am missing something, I'd love to hear it.

    Cheerio!

    John

  12. #26
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    Quote Originally Posted by ian View Post
    I may have more time to comment later, but for now please be aware that there is a simple (and at the same time complex) relationship between the seat height of a chair and a table's top and apron.

    if a seat is too high your legs won't comfortably fit under the table

    if the seat is too low using the table -- in your case eating your dinner -- is uncomfortable.

    Joints
    I agree with Alex, floating tenons
    I bought a rectangular table and 16 chairs years ago during a sale. Having determined that the table and chairs were a comfortable fit I built a square table for the formal area (the rectangular table was in the family room) copying the height and apron size of the existing table. It worked, of course. The new table will be the same height, the apron will be the same depth, and the chairs will be the same height as those currently in use.

    A floating tenon will be used to join the back of the chairs to the rear rail. However, the current plan is to cut tenons for the chair rails because the rails will not fit into my morticer and because I have never cut mortices with a router ... don't really want to start right now.

    I understand the comment about repairability, but am more focussed on building the chairs so they don't need repair. The existing chairs are 12 years old and apart from a few vacuum cleaner marks on the legs, are in perfect shape. I'd like to think I can do a better job that the shop in Asia that made those chairs.

    Have fun!

    John

  13. #27
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    Two other ways of doing the upholstery that differ from your drawing on the right.

    In the first picture the rails for the chair are rebated before assembly to take a seat frame ,the tops of the legs have to be chiseled or routed out. The frame is usually made from roughly 48 x 19 timber and sits in a 19mm rebate

    The second cheaper method is to upholster a 12mm plywood board and fit it to the top of the chair frame . You could screw it with holes through the rails .
    Attached Images Attached Images

  14. #28
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    Hi John

    some more considerations

    Normally a chair's back seat rail (frame member) is shorter than the front one
    Normally the back of a chair seat is lower than the front
    This leads to the need to cut angled tenons (in two planes) on the side rails -- don't try to avoid this "complication" as it adds to the look and comfort of a chair.

    also, design to avoid using corner blocks,
    you can add them to help support a slip in seat -- just don't design yur joins to rely on the corner blocks for strength

    enjoy the journey
    regards from Alberta, Canada

    ian

  15. #29
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    Quote Originally Posted by auscab View Post
    Two other ways of doing the upholstery that differ from your drawing on the right.

    In the first picture the rails for the chair are rebated before assembly to take a seat frame ,the tops of the legs have to be chiseled or routed out. The frame is usually made from roughly 48 x 19 timber and sits in a 19mm rebate

    The second cheaper method is to upholster a 12mm plywood board and fit it to the top of the chair frame . You could screw it with holes through the rails .
    Trying to avoid the second method, which is how the existing chairs are made.

    48 mm wide timber for the upholstered frame is a lot more than I was considering ... that means the backside sitting in the chair would feel these timbers, does it not ... or am I missing something?

    Cheerio!

    John

  16. #30
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    Quote Originally Posted by ian View Post
    also, design to avoid using corner blocks,
    you can add them to help support a slip in seat -- just don't design yur joins to rely on the corner blocks for strength

    enjoy the journey
    Ian,

    Agree completely that the design should not rely on blocking of corners. Well made M&T joints should do the primary job. However, will likely sit the upholstered frame on corner blocks because it is a quick and simple way to add a bit of strength. The geometry has the tenons closer to the outside of the rail than to the inside (so that in the leg there is wood between the two tenons approaching each other at right angles). So, my guess is that when I look at the moments and fulcrums (and where the joint would be in compression or tension) in the joint that the weakest part of the joint between the rail and the leg will be the inside of the joint. Corner blocking would likely add strength where it will do the most good.

    Still struggling with how to cater with the angled tenons. I could cut the tenons on an angle, or I could angle the edges of the leg and leave the tenons square. However, the latter exposes angled joints ... does that matter?

    Have fun!

    John

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