A buddy came into my shop the other day and thought this jig was the craziest thing he had ever seen, but when I told him what it does, he took a picture so he could use it at his shop...

Can you guess what it does?  Hint: I'm making chairs.





I'll post the answer tomorrow.

I like that ball on the end of the rail. It makes me think you've encountered sensitive parts of your body with that rail from time to time and finally got tired of it.

Hey Don,
As you can tell, the shop needs a good cleaning before I take shots.  After I finish this batch of chairs maybe.
Jess

What about some pics of finished chairs   

Woodguy.

A third hand during assembly; you clamp legs/back to the vertical to hold them there while you finish the assembly.

I like the cabinets in the background.  Look like spalted maple with big trunk hinges.

I prefer to think of tennis when I hear the expression, "the ball's in your court."       

I'm going with the "third hand for assembly" idea and the three sided shelf comes into play also somehow -- it's on the wrong end of the MFT (& backward?) for a saw rest.

Lots of good answers!  Rob-GB's was the most complete.

When I make a chair, I finish and glue up the rear assembly (rear legs, rear stretcher, back splat or spindles).   There are lots of tricky compound angles in most chairs.  The rear legs splay outwards for stability.  The back of the chair seat is lower than the front for comfort.  Half a degree off here or there can make a big gap, so I cut the last pieces to fit.

The jig holds the finished rear assembly vertical with the front legs and stretchers dry fit.  I then fit the front stretcher to the gap between the front legs and scribe the front legs against the edge of the mft to find the final length of the legs.




All the joinery is done while the pieces are square or rough.  After a successful dry fit, I will finish the pieces, glue the front assembly up and then glue the assemblies together with the side stretcher.  Then corner blocks, a slip seat, and leather upholstery and I'm done.... some day

Thanks for playing the puzzle - great answers.

Ooh, thats evil. I love it! Lets move it off by 1/2 a degree?

@Chris and David - you guys are evil!

@Woodguy - Yes, the backsplat is laminated.  Plain maple in the middle, curly maple veneer on the show faces.  The interesting part was getting the negative space in the curved piece.  I used the template for the laminating form to make a 'cutting board' with the same shape, made a router guide out of a scrap piece of laminated curve and routed it with a couple of different sized bits.   I will do the upholstery myself on this one, just a simple slip seat.  Will take pics if anyone is interested, the good part is that there is no sewing, just a cool air stapler.

Thanks for looking.
Jess

Wow, I watched the video and Joseph Walsh is incredible.  Wish I had that kind of creative imagination.  Be sure and post some pics when you get back to your figure of 6 chair.   BTW, I never learned how to stitch leather, maybe if I ever get wood figured out.

Hey Jesse,

I think you mentioned at the advanced routers end-user training that you were using dominos in your chairs.  If this is correct, which part(s) of the chair in the picture is assembled using dominos?

Nice chair by the way... it's giving me some inspiration to build a dining set... especially if the domino is involved, which I still need to purchase.

Thanks,
Corey
U.P. of Michigan

Hey Corey,
In this chair, the only dominoes are those that connect the crest rail to the tops of the rear legs.  And oh yeah, the backsplat enters the rear stretcher at a 15 degree angle.  Made that mortise with two side by side cuts with the domino.  Next chair I do, I think I will use the Domino for all the joinery.  Will probably use twin dominoes with one pair going in higher than the other, say the pair connecting the rear stretcher could be above the pair connecting the side stretcher.

One thing for sure, glad I'm not trying to make a living building chairs!   

Jess

The new avatar is from an exhibition of Henry Moore's sculpture in the Denver Botanical Gardens.  They have 18 large pieces spread throughout the garden, many in the middle of water features with great reflections.  Well worth a visit if anyone is in the area.