Saturday, May 30, 2015

Dining Set Tutorial #1 - Design Process and Back Chair Legs.

A dining set is quite an undertaking for any woodworker, but I seem to enjoy the challenge. There's a few folks who requested that I blog my process so this my attempt to oblige. Now, this won't be completely comprehensive, but it will show each step and point out things I think important. That said, I try new methods and learn new things with everything I build, you'll get to see some of that too.

Design...


Here we go. After getting a good idea from my aunt and uncle (whom I call "clients" for the rest of the blog, to keep it all professional-like) of what they'd like as far as wood species and design, I set out to designing the rear chair legs. My clients fancied the chair legs in this picture:

Photo from Branchhill.com



Which is cool, because I'm fond of these chairs too. On later entries I'll delve into custom design features of the set I'm building for them, but here's some to give you an idea:
  • All solid wood, mortise and tenon joinery. Sorta Amish in style. 
  • Solid sculpted seats. 
  • The set will have a natural two-tone look. Black walnut on everything except the tabletop and chair back slats. They will be cherry.
  • The table with be 48" square without the leaf. Add an 18" leaf to make it about 66". I'll likely get the leaf mechanism from Osborne Wood products. 
  • Six chairs total, two of them captain with armrests. And a kicker, the captains chairs will have a more sculpted back. My uncle must have the Westfall curse too- a bad back. 

Now, onto chair design. No matter how crazy folks like to get designing a chair, we're all still locked within the confines of ergonomics and comfort for the average human being. Just like Terry Moore's diagram in Fine Woodworking shows (below), you really need to get the seat height between 16-18 inches, and so on.



Yep, you can splay the legs all crazy, do whatever you want aesthetically, but if you don't stay within these perimeters, the chair won't be comfortable. Some furniture makers/designers get into trouble this way. They try to shake things up with an innovative designs. While their chair make look awesome, it feels like sitting on two logs.

Realizing these parameters makes it easier than one would think to design a chair from just a picture. I brought to my bench a copy of that dining set, my calipers, dividers, and some old chair leg templates. This is what I came up with:



This might not be the exact back leg design as the chairs in the first picture, but I'll bet its pretty dang close. I realize designing a chair is not going to be as simple for everyone. If this is you first attempt at chairs, I recommend working with a plan like Kevin Rodels in Fine Woodworking. After you've built a few, you'll get confidence to branch out from plans.

And Build...


Ok, I'm happy with the design, let's get to work.

First I selected sections of nice, straight grained (preferably riftsawn) 8/4 walnut stock and milled it all down to 1 5/8". (this is thicker than most furniture mart chairs, but most of their chairs fail in time). I laid the pattern out and traced with an orange wax pencil so it would be visible on the dark wood. Then I carefully cut them all out on the bandsaw.



Then it's on to some pattern or "template routing." Deep down I wish there was an efficient way to batch out large curved parts with hand tools, but it doesn't exist. Template routing is very efficient so I keep coming back to it.

Sure wish this bugger was a spiral bit. I had some minor tearout issues.

There are lots of articles and tutorials out there template routing so I won't go too in depth. You can see in the picture above that the bearing guided bit just follow my template. The piece of walnut is held in the pattern with some temporary screws that are strategically placed where future mortises will be. The screwed side is down so the template won't move.

Then I remove the pattern and bust out a edge trimming bit for the waste on the side. The picture below is staged just to convey the idea:



A few thoughts on template routing:
  • All the safety rules of routers apply. Use push sticks and understand feed direction. 
  • Get as close as you can with the bandsaw. Re-trim after your first cuts if needed. If you try to remove more than 1/8" with the router, you'll run into trouble. 
  • Going against the grain can and will cause tearout. "Climb cuts" are a spicy option if you want to look that up. However, spiral bits really are the solution, albeit a pricey one. You can see in the pictures I had a spiral bit for the second half of this operation, and after some frustration yesterday I ordered this beast(below) to help with the curved backs. At $135, it's not cheap, but neither is tearing up a bunch of expensive hardwoods.
Big Daddy spiral bit by
William Ng Woodworks



If it's your first time template routing out a bunch of parts, cut yourself an extra part or two to begin with. Your bound to botch one. I did yesterday. But, after about three hours of work I've got my rear legs. Eventually they'll be cleaned up and smoothed with hand tools.




That's it for now. May not seem like much, but making a nice and uniform set of rear chair legs are nothing to shake a stick at. Up next milling a bunch of parts and more more parts, including rails with angled tenons.

Shoot me any questions you might have in the comments below.

Take care,

Dan Westfall






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