I cut notches in the edge of 1/2″ maple box carcass last night. These were to receive wooden latch pieces glued in. On the first notch (1/2″ wide by 1/4″ deep) although I used the inset latch piece to mark the sides of the notch somehow (Beats me) it still was too wide at the top by 1/16″. I was hoping for a real tight-looking fit. Is there a reliable way to get this kind of fit when doing this with a chisel?
I also noticed that it is very difficult to know when the bottom of the notch is flat and level? Any suggestions on this? I wound up fitting the latch piece into the notch and looking at it from about 6 different views to try to see where the high spots might be. I finally lucked out and hit the high spot but it was only by luck that I found it.
Replies
As a general rule, when chiseling to a marked line, you want to work toward to the line gradually, rather than starting right on the line. If you put the edge of your chisel on the mark, and give it a whack, the chisel acts like a wedge, crushing wood fibers on both sides of the line and elongating the notch (or mortise, or whatever). Ideally, the final cut on the line should be a light paring cut, removing just a thin shaving of material. Clamping a guide block over the mark helps also.
If I'm visualizing your stiuation correctly, it might be best to saw the sides of the notch first, then pare to fit with a chisel.
Thanks, Kent. You are probably right in your diagnosis. I did try the mallet to chisel approach for the first effort on the first notch. Quickly realized that I was not going to get far with that method in the maple. So switched to small Japanese saw and moved in toward the center to cut kerfs just short of depth and then used chisel to break debris out and then pare and shave my way to a flat bottom. I then pared the ends of the notch using the first strike mark as my starting point so that was probably how I got it too big. Thanks again.
Chopping the slot...
Chop little 'V's' while increasing the depth along the length of the slot. Keep the back edge of the chisel toward the middle except for the paring cuts at the end of the mortise.
I also noticed that it is very difficult to know when the bottom of the notch is flat and level? ..
I use a small wooden stick as a depth guage and a sokozarai nomi (bottom cleaning chisel). I do not have a picture of it but it is just a chisel with a sort of hook on the end like a scraper.
Also something I use from Making Shoji by Toshio Odate..
A small dish filled with cotton and vegetable oil. Dip the chisel point into the cotton and oil it often to lubricate the cutting edge.
Thanks Will, that looks like a good method to follow. I'll try that next time.
Are you marking from the hardware with a pencil or knife? Are you using a narrower chisel than 1/2"? If you're using 1/2, it's too easy end up with the slot wider than 1/2" - I'd use a 3/8 and gradually work up to the side lines.
The depth aspect is a little tough to get right. If I'm having trouble, I sometimes take a 6" combo square and a straight edge and set the square's blade to project the thickness of the straight edge plus the thickness of the hardware. Then straddle the straight edge across the notch, set the square on it, and see where the square hits to figure out where to go deeper. You can do the same thing with the depth rod on a dial caliper if it's one of the locking types.
If you build it - he will come.
I marked with a .5mm pencil and then cut inside the line. Thanks for the combo square suggestion - I'll look at that.
To all who answered, thanks for your help. Your various suggestions/instructions have given me better insight for the future. I think one thing, I should definitely do is make the notch in a piece of 1/2" scrap first and verify that it fits like I want and then clamp that to my project as a fixture/jig(?) to give me a hard guide for the chisel. Thanks again for your help!
You might get a little better results if you trace with a sharp knife. I still take a 0.5mm pencil and darken the knife line just so I can see it better. But the knife line cut will act as a guide for your chisel and help make your initial chisel cuts more accurate.
If you build it - he will come.
Pat, to 'Bed' the cabinet lock body, after excising the bulk of the mortise,use a soft blunt pencil to lightly shade the bottom of thelock body.(Case) When the lockcase is rubbed against the incised area, some of the 'Highspots' are indicated by the carbon black.
By continiously paring/chipping and shading, the mortice will arrive at the right depth.
It's important when mortising a small box to clamp it down or at least place the box upon a thick slab of metal. You'll find less bounce due to the damping effect.
Also,better control of the chisel. Steinmetz.
Edited 3/14/2005 10:35 pm ET by steinmetz
Thanks, I have used a similar method for other applications - don't know why I didn't think of it here.
Pat,I forgot to mention using a small router plane
to excise the lock mortise
It has to be continously adjusted
'till you reach the final depth, BUT, If you set the iron to full depth,
you can add shims in 1/8" increments,
then remove the top one, rout, remove one shim,
rout, etc etc.
The shims have to have a center hole of 3/4" or so, to admit the iron. Steinmetz.
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