[OP]
Member
I tried to do it on a project I was working on and I did not have a good time. My very sharp chisel could cleanly cut into the into mortise, but I couldn't get the waste to clear from the sides. It would just pull and splinter and crack.
Is there a technique to it or is this another case of a novice learning an important lesson through error?
Contributor
It may be dependent on the wood you were using.
After all, a dado is a type of cross grain mortise.
The sides are usually saw cut or knifed.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Guest
Drill and pare.
Contributor
I'm no expert but I've worked some of these like a short wide mortise. Chopping perpendicular to the grain to make 2" mortise that's 1/4" long.
-- Dan Rode
"We are what we repeatedly do. Excellence, then, is not an act, but a habit." - Aristotle
Contributor
Be careful with cross grain mortise and tenon. The end grain does not glue well, even to long grain. You'd do better to make two mortise and tenons in the piece and go with the grain. You want long grain to long grain on the face of the mortise and tenon.
Mike
Go into the world and do well. But more importantly, go into the world and do good.
Member
+1 On the divider below drawers it is very common to make a double mortise & tenon for exactly this reason.
Member
I use slip tenons in such a case. It works.
Member
+1 on this.Originally Posted by Jim Koepke
What species are you mortising?
Contributor
I did it on this spalted maple stool. Drill and pare is the key. Make sure your chisels are razor sharp and take light cuts.
Sharp solves all manner of problems.
Member
And make sure you create a knifewal in the sides first where you would get splintering otherwise. It's a lot more work then a normal mortise, because you have to tend to the sidewalls too and because the waste doesn't come out so easilly.
Member
Just an observation: on that table top gravity and wedges hold the tenons into the mortise, the strength of the glue is largely irrelevant.
I did it on this spalted maple stool. Drill and pare is the key. Make sure your chisels are razor sharp and take light cuts.
Contributor
Perhaps I'm nit picking but I would not use a wedged tenon parallel to the grain. The wedge, AFAIK, should be perpendicular to the grain to avoid potentially splitting the mortised piece.
-- Dan Rode
"We are what we repeatedly do. Excellence, then, is not an act, but a habit." - Aristotle
Member
I miss read the question.
When I built the bench that Rob showed, I chopped the mortises with a chisel. Of course I was using pine. Some more brittle woods might present a problem.
In such a case, I would drill holes and clean up the edges with chisels.
Last edited by lowell holmes; 11-21-2014 at 4:19 PM.
Contributor
I think the wedges are more effective than the gravity, but correct on both counts. No glue at all used on this stool except for the dowels that hold the side gussets in their mortises. It's rock solid. I've used this technique on a couple other projects too, including the hall table below. The lower shelf is mortised into the ends. I used some oak wedges there, and they pretty much just disappeared once I applied the finish.
Wedged or pinned tenons have kind of become my MO. I still use glue where it makes sense, but I like the belt and suspenders approach in addition to the aesthetic.
Sharp solves all manner of problems.
Contributor
Jared,
As I was working on a tea cabinet for the LOML, this thread came to mind.
This is one way that works for me.
First the area is marked out. I set the width of the dado/mortise to a chisel. Then a wide chisel is used to deepen the scribe lines:
Cutting the Scribe.jpg
Do this before cutting the ends of the dado/mortise with the grain to avoid splitting. For this shallow dado the deepening of the scribe lines had to be repeated three or four times before reaching the desired depth. For a through mortise one would want to carefully mark from both sides and cut the mortise from both sides.
The wedging action of the chisel's bevel will widen the dado/mortise a hair.
The marked lines should be just a hair wider apart than the chisel used to pare out the waste in order to avoid tearing out the top surface when removing the waste.
Curling the Waste.jpg
If material is cut below the scribed lines you get this:
The Fuzzies.jpg
Hope this helps.
jtk
Last edited by Jim Koepke; 11-23-2014 at 8:32 PM.
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
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