An important part of chairmaking is knowing how tight to make a joint in order to get a proper fit. How tight I make a joint will depend somewhat on the type of wood used but, essentially, I want it as tight as possible without splitting the joint - and having to use a little force to bring it together is not necessarily a bad thing.
A good rule of thumb for testing a windsor chairmaking mortise and tenon joint is if you can put the joint about half way together with only hand pressure then you are about perfect. Then during assembly you can force it togther with a few hammer blows.
In windsor chairmaking, you are not often putting multiple joints together at once so a tight fit like this is possible without complicating a smooth assembly. On the other hand, with a post and rung assembly, I will back it off just a hair so I can have a bit more control on an assembly. When you add up a lot of joints that have to come together at the same time on one of these chairs then the extra give can be the difference between success and a struggle or failure.
Here is a short (and very out of focus) video of how tight I try to make the joints for a post and rung chair joint.
I wanted to give a little sample of a glue up of a post and rung assembly. This is not the entire process but my hope is to share some little details about applying the glue and how to clean it up as you go along. These things are not often discussed in books but it is helpful to see how it is done so that your process goes cleanly and smoothly.
I use hot hide glue exclusively in chairmaking. Using PVA glues, or just about anything else, is simply madness if you plan to have well fitted joints. PVA glues will bind up in a split second in a really tight joint and will stop it from going together completely. On the other hand, hide glue will actually lubricate a joint making tight fitting ones come together more easily
You'll notice the first tool of the trade here is a good stiff bristle brush for wiping away the excess glue. This is just a cheap natural hair brush from a hardware store with the bristles cut way back near the base. Removing the majority of the glue this way keeps you from smearing it around and then worrying about getting it all wiped off. Also, try to avoid adding any water to the surface as you clean so that you do not dilute the glue and spread it around even more. That said, slightly damp cleaning tools may help lift the glue better.
Your next tool is going to be paper towel for cleaning the joints. This may prick your eco-friendly conscience but a clean surface each time to remove the glue is, in my opinion, the only way to go. Using a wet rag will only spread it around for you to fuss with later before finishing. Plus, a paper towel will pick up the glue off the surface better than a rag.
Lastly, be sure to use something like an old magazine under your work so that you don't damage the side that is on your workbench.
I first learned most of these methods from Peter Galbert. If you have heard about his upcoming book from Lost Arts Press and are wondering what to expect, this is the sort of detail that he covers. It seems nothing is left to guesswork.
Even though I read and helped edit most of the text early on I can't wait to get my hands on the finished copy. Chris and Megan did a really great job of compiling the book into a super easy to read style that is a hallmark of LAP publications. Plus, Pete went back and reworked a lot of the drawings and I haven't seen all of those yet. Very eager. Come on Chris, get that thing to the printers!!!!!
When it comes to making certain moulding profiles you have to take into consideration how the sole of the plane will hold up to heavy wear. If the profile focuses a lot of friction on a relatively small area then it will likely not hold up very long.
A very good example is the quirk of a beading plane. You simple don't see beading planes without boxing. The quirk would very quickly wear away without it.
There are other places that you would see boxing used in profiles and even boxing for fences. I talk more in-depth about boxing in a post here.
I thought it would be interesting to share my approach to installing boxing via a video. The process is essentially to make strips of boxing. It is not easily described how I rough out the boxing strips but it involves a slot cutter. All the strips are roughed out over size and then individually fitted to the groove cut in the plane body. I cut this groove at the table saw.
The process is involved but when done right it can be glued in with hide glue and just tapped into place with a hammer and that is it. I do not use any clamps to secure the boxing while it drys. Even without the glue the boxing would be difficult to remove just on the friction needed to tap it into place.
This is an approach I learned while fitting mortice and tenon joints in chairmaking. If you could push the tenon in about half way and it stops without using more force (hammer) then you have a perfect fit that glue only adds a bit more confidence in the joint withstanding stresses in use. The hide glue also acts as a lubricant to make tight joints slide together, unlike a PVA which would bind and lock up in this situation.
You'll notice that the video ends suddenly since my memory ran out right at the end but you get the gist of the process from this video. :)
