Friday, November 16, 2012

Glueless

For years now I've thought and taught that glue should be a back up for already solid joints. It's a belt and suspenders approach. But there has always been a nagging curiosity as to how a chair would hold up without the glue.
So as I went about finishing up a chair that I started during my demonstrations in Rochester, I figured, why not give it a go. And even without knowing the long term results, I have already realized some benefits of the attempt.






In making the joints, I use air dried mortises and kiln dried tenons so that the joint benefits from the swelling of the tenons as the moisture contents equalize.
When I started to put this chair together without the glue, I found my focus on the fit of the joints slightly elevated. Not profoundly, but I suppose that driving the joints all the way home without the glue made for a different experience. The ring that wood on wood joints make when seated is very gratifying.
There is also that little space that generally has to be allotted for the thickness of the glue film, but in this case, I went for the absolute tightest joint that I could manage without blowing out the mortise.

As I turn my attention to the top of the chair, I am thinking a great deal about the joints where the short spindles pass through the thin continuous arm. Without the glue, I am definitely going to make each one a sort of "hammer eye" joint by having a subtle shoulder on the spindle so the arm can't shift down and flaring the top of the mortise so that the wedge will spread the spindle enough so that arm cannot move up.
It may seem like a silly esoteric exercise, but I am thoroughly intrigued as I think and rethink each of the joints and what it takes to count on them without glue. Of course, time will tell which joints loosen, and it will be fun to live with it, watch and learn. I think I'll paint it blue.

9 comments:

ChrisHasFlair said...

Peter,

That's a very interesting experiment. Thanks for sharing your thoughts.

Chris

Caleb James said...

Pete,

try using your cello reamer for the spindle joints. I have a custom "sharpener" matched to the cello reamer. You will find that if you drill the spindle hole at 5/16" then the bottom of a typical arm bow will be almost exactly 3/8" once it has been reamed. This works perfectly for sizing the spindle to 3/8" then just "sharpen" the spindle down to the shoulder of the tenon. Try it, I think you will like it.

By the way this works really great for the blind spindle as well. Your reamer may be different but mine has a tip that is just shy of 5/16".

Robert said...

Peter that is amazing. I was thinking of doing something similar.I am building the rails for my log cabin in Colorado is there a ratio between how much drier will be the tenon versus the mortise? If the difference is too much, will the mortise piece split?

Pagie's Boats said...

Watching with interest. Blue means no glue.

Bern said...

Pete, I think it must be a profoundly gratifying experience to go glueless, though I do wonder if the chair wouldn't become like an arthritic old man through the change of seasons. Unlike a drawbored joint I can imagine wedged tenons having annual dance parties. Or not.
I like it a lot though.

Anonymous said...

Hi Peter,
I follow your blog because I am addicted to chairs and I find your design flourishes beautiful. I'm contemplating building some of my own just for fun. I've notices some builders orient the seat board grain side to side and some front to back. What is the thinking behind this?
Peace,
Harlan Barnhart

chairs said...

for me wood furniture is more beautiful when painted with varnish, it show natural look of the wood.

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greg said...

Harlan,
Seat grain orientation has to do with limiting how wide the boards have to be, as far as I know. Ideally the grain would run front-to-back on all chairs; but boards don't typically come wide enough for some of the wide seated chairs to be build that way. You will generally find sack backs and settees with their seat grain running side-to-side because of the width of the seat. For braced chairs front-to-back grain orientation is even more important because the thin cross section of the key stone shaped piece that comes off the back of the chair for the brace requires it. A braced sack back will always have the brace's extension morticed into the seat to get around this. Plus with this morticed add-on the boards don't have to be as wide as if you cut the piece out as an intregal piece of the board.

Then there's the answer: "Just because that's the way they do it."