So I’m cruising along on my little Byrdcliffe-inspired cabinet and I run headlong into the door, specifically the mortise and tenon joints on the door frame. The carcase of the cabinet is all glued up, nice and square with nice night joints.
But the mortises for the door frame are giving me fits. I’ve made a handful of mortise and tenon joints – a small enough number that I can probably count them on my fingers – over the past two years. Generally I’ve used a router or drill to clear the waste and squared things up with a chisel. On a few I’ve chopped them directly, which felt pretty good. There is a joint on the Blacker House sconces that makes a L-bracket to hold the sconce body, I chopped a pair of mortises for that joint that came out pretty nice.
I know from experience that if the mortises on this door are just right the door won’t be right either. The mortises need to fit the tenons nice and snugly so there is a reliable glue surface, and they need to be exactly true or the door don’t lay flat on the bench. Ask me how I know that, go ahead…
So yesterday I ended up chopping bunches of mortises for practice. It wasn’t much fun, kind of frustrating because I don’t seem to be progressing past a point.
My initial problem was glowing out the end, but I can avoid that by making the stiles over-long and then trimming them to length after the door is assembled.
I tried pre-drilling the mortise, but on this particular mortise that just gave me a sloppy, wallowed-out slot. The drill bit wanders a little, and truthfully it didn’t really seem any faster to me.
So I practiced chopping mortises with both a regular 1/4″ chisel and an English-style mortise chisel. I think there is something wrong with the geometry of the mortise chisel as it tends to stick in the mortise. I’ll have to check it with some calipers, but I think it’s wider behind the cutting edge. It’s a lot harder to keep it aligned too, the shaft isn’t as true and my LN chisel. I suspect that is a factor in my difficulty in getting the mortises truly plumb.
Here is what I’ve found so far. Having the workpiece (and mortise) oriented so it is straight in front of me make it loads easier to keep the chisel plumb and have the mortise end up mostly straight. But none of my mortises so far have been straight enough. I have a piece of scrap that I test fit in each, and it’s never quite right. Generally it leans away from the rabbeted shoulder slightly, which isn’t going to work. I can pare the mortise to get it to stand straight, but then it’s too loose.
The other thing I’ve found is that it’s relatively easy to get a 3/4″ deep mortise, but getting to a full inch across the whole mortise take a lot more work. I don’t know if that’s technique or what. I’ve been using the “Central V” approach, I’ll have to experiment with other approaches. In fact, as I write this I’m remembering a blog post by Chris Schwartz that talked about his struggles with mortising, and I’m already feeling better. In his article, he mentions another site that has a number of great articles on hand mortising, I’m going to read all of those articles today, and do some more practicing tonight.