I described how to hand chop a mortise in a recent comment. Another LJ member asked if I would do a blog with photos on it. I learned this technique some years ago from an article in Woodworker’s Journal by Ian Kirby a master English woodworker who immigrated to the U.S.A. Some time ago. His method is quick and accurate.
I hand chop mortises when I have so few to do that it isn’t worth the effort of setting up my mortiser attachment to my combination woodworking machine and/or when I have real long clumsy pieces that aren’t easy to clamp onto my mortising table. For those who use routers for mortising, you might want to hand chop when you don’t have a bit that is long enough to do the depth of mortise you desire.
Here is what you need to do the job. Please note that I have used a bench chisel with beveled side edges on the blade. A better choice would be a mortise chisel which is thicker and without beveled blade edges. However, they are hard to find in Norway, and expense. The bench chisel works pretty good, but you will just have find it’s limitations through experience.
The first thing is to select a chisel that will be the same width of your mortise. This is important unless you want to use a lot of time chopping and shaving the sides of the mortise.
Here I am making the first cut. Note that the flat side of the chisel is facing the middle of the mortise. Keep the chisel vertical. When you strike it the bevel will make the chisel cut in the direction of the mortise center line.
Here I’m making the 2nd cut from the other end of the mortise. The chisel has been again positioned with the flat side towards the middle.
This is the result of the first cut. You have to lever he chips out with the chisel’s bevel and the hole edge acting as the fulcrum.
Repeating the sequence of the first cut gives the results of the 2nd cut. The board has been turned around end for end, Looks a little confusing, sorry.
After the 3rd cut.
After the 4th cut. Note that I stopped about 1/16” short of the end lines. This way you don’t ruin the finished edges while levering the chips out.
Now the mortise ends are being chopped vertical to prepare for the fine chopping to the end lines.The idea is that when you chop to the line there will be so little material left that you won’t have to lever it out and ruin your nice fresh ends.
Final Chopping or the mortise ends and some cleanup on the bottom and the corners. You will probably notice that there are levering marks on one end of the mortise. I put those there to show what happens if you lever against the end edges(LOL). If you have done a good job of holding your chisel straight while striking it you won’t have to do much on the sides. If you are a little incompetent like me you might have to take a few shavings there as well. This is not a fine woodworking mortise, but it isn’t too bad either. I had to do a fast and dirty job on this today due to a few small catastrophes. My computer router went out late in the day and had to be replaced. and I also wasted a lot of time on a scrollsaw job that I messed up and have to do over again. In other words, just a normal day at my house. I haven’t been scroll sawing lately, so I guess I really need some practice as I have gone from bad to worse.
Marking up for the tenon.
The tenon marked out. It’s length is about 1-3/4”, a little under the depth of the mortise.
Quick freehand cut on the bandsaw (not particularly recommended).
Trial fit. Not too bad, the tenon needs a little shaving. I like to cut the tenon a little oversize so I can make sure to get a good fit with small adjustments.
Ok. Here’s the final joint. Ignore the lever marks on the one end of the mortise. YOU are not allowed to do this!
A proper tenon should have a shoulder on the ends too, but I didn’t bother with it for this blog. Granted this is not Fine Woodworking Magazine quality appearance, but I’ve been doing it for some years. I hand chopped mortises into the wall supports for my timber rack which is pine, and I have been storing quite a lot of weight on it’s 3 shelves for 7 or 8 years and the shelf supports which are tenoned into wall supports are just as solid as when I joined them.
Well, another windy blog. For you old hands who can do it better than me and wonder why I have put so many words and photos in, I just want the novice woodworkers who are interested to get the whole lowdown. I remember when I started out there was always some essential info missing which made me go wrong more than once, so I wanted to cover it as well as I could.
Thanks for reading this. If even only one woodworker gets some good out of it I will consider it worth the effort.
-- Mike, American in Norway