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.

Enjoy!

Drilling - Post and Rung

Yet more on drilling... Lets look at how I approach drilling for a Danish Modern chair frame. Naturally the tooling that was in vogue during the time a chair was designed and produced will often suit the production of that style the easiest even if other means are developed later on. I find that especially true of windsor pieces. That is why I will do almost all drilling free hand on those pieces but for the Danish Modern pieces most holes will be done on a drill press or even slot mortiser. I will cover the latter method in a future post, which is a must have tool for Wegner designs.

So lets look at my drill press set up. I use a jig that without would otherwise make drilling a post and rung chair a real fumbling awkward mess. I have seen a number of descriptions of ways to do this but none that don't require something that is specific to each chair design. This jig is just a platform that I can set a specific angle on. It will drill anything from 0º-25º.

Here is how it works. A round dowel is drawn forward or backwards by a treaded shaft. The dowel makes contact with an angled bracket pushing the platform up or lowering it.

I use a cordless drill to drive the shaft, for the sake of speed. 

Here are a few photos of a post beginning prepared to drill. The pictures are pretty self explanatory on the order of set up.

The angle is set by a simple gravity/plum bob type angle gage that you can purchase at any home improvement store. I compare the chuck or bit angle to the platform and just adjust the platform to the angle in relation to it.

 I use an additional platform with a "V" groove to hold a round part stationary. Square it to the platform edge. Add a clamp to hold it still. (not shown)

Center it on the groove.

Drill!

For posts that are tapered, leave an end on your turning that is equal to the diameter of the largest portion of your turning. This will allow you to base your angle of the hole being drilled on the center line of the part rather than any angled taper.

I will almost always start by drilling the front and rear post and assemble a right half and a left half of a frame. Then follow by drilling the remaining holes on one of the assembled halves at a time then complete by mortising or drilling for the back rest/supports. Now assemble the two halves into a whole. Doing it this way makes the assembly more accurate than trying to drill all the holes and then assembling. 

This is the simplest most versatile method I have come to use so far. I will follow up with some discussion of how you can use this jig in connection with sighting angles to drill compound angles. This is really useful for drilling the holes in the back of an elbow chair or something similar.