Wednesday, October 30, 2013

Danish Modern Chair Joinery - Using the Slot Mortiser

I know that when you look at a Danish modern chair there are a few kinds of joints that we are not familiar with in our western chair making. The rectilinear cylindrical shaped cross rails as well as multiple rails entering at the same height 90˚ to each other on a relatively small post. I think the only perspective most of us have is what Sam Maloof did with some of his chairs when joining the arm rest to the front leg post. Though that is not the joint I will be discussing now. I think it is no coincidence, by the way, that his chairs reflect the Danish design movements considering he made his chairs during the period of the mass production of Wegner and in particular Møller chairs. 

Since I mentioned Sam Maloof then I think something I recently read about him in the Los Angeles Times said with regard to his thinking about sharing his knowledge that I can completely agree with and reflects my thinking as to what motivates my blogging. It is a paraphrase of something he said- "'He didn't believe in keeping trade secrets and was eager to share knowledge earned through trial and error to save what he called "a struggling craftsman" hours of frustration.'" Hopefully this post saves you some time.

So here is how I cut the joints for a rectilinear cylindrical cross rails ( Not sure if that is the right way to describe that shape?).  I think a video is appropriate to show this. This blog post is a long time in coming as I did this video about two years ago and it just sat on my computer until now. This is a leg for my Elbow inspired chair but is the same for any other chair of this type. Notice how I use my angle gage to orient my leg to the angle that I want to mortise my rail in relation to my rung mortise.

This is not how the joint is made in the factory. I didn't know this when I started making Wegner chairs. The factory chair have a specialty shaped shaper that cuts a tenon that is narrower than the rail and it leaves a shoulder that conforms to the shape of the leg. It is great because it leaves more material for the post and it also simplifies assembly. The method I use lets me be more flexable in my design because I can change the designs without worrying about getting a new custom shaped cutter head. If I were doing mass production then that would be a different story. The drawback in my method requires that a joint without a shoulder be cut exactly dead on otherwise there will be a gap in the joint. The assembly is also a bit more tedious. Maybe I will change someday but it is how I like to work for now.

Here is a video that I found on You Tube that shows some of the joinery being made at the factory producing some Wegner chairs. It gives some great insights to their processes and the "shop made" type jigs they use. It is pretty cool. There is some unique tooling I have never seen before. Click here to go straight to the joinery part of the video discussed or I encourage you to watch the whole video below.

The joint for the weaving rungs are cut in a similar way in the factory produced Wegner pieces. This makes the angle of the rung set exactly during assembly. However, I simply use a round mortise and tenon and set the angle during assembly.

I will follow with a discussion on how to make the joints for rails that meet at the same height on a post 90˚ to one another.



  1. Your wood work is good. Chairs are looking stylish and reliable also. You people Use the Slot Mortiser in creating your chairs, which is the new thing.