Sunday, May 28, 2017

Chopping Mortises

I'm making a side table for the girl child, The top will be a frame and substrate to hold one of MsBubba's ceramic mosaics. The base is some near 8/4 Sapele I had in the shop.

The top is made, it just needs cleaning up and the legs are dimensioned but not shaped. The aprons are dimensioned waiting to saw the tenons once I finish chopping the mortises. I'm half way through chopping the mortises, two legs finished and two to go.

While chopping the mortises I thought about making a post about technique. My guess is everyone has either tried and discarded this technique or they are currently using it and it is no big deal because I have a history of riding the short bus. Anyway one of the problems I've always had with chopping mortises is keeping the hole straight. To fix that I've started knifing the reference mark, the one on the face side and then coming back and undercutting the knife line. This gives a nice "v" grove on the reference mark that give a positive stop for the mortise chisel. Angle the chisel slightly, drag it to the reference mark, when it stops stand it upright and square, give it a whack. Lever and repeat until you have removed everything that doesn't look like a mortise hole.

A couple or three photos, I don't know if you can see but click 'em to big 'em and whatever, one is of the mortise.

Knifing the reference mark.

Cutting the grove:

The mortise hole:

One other thing I happened to find today. My favorite pig sticker it turns out is 5/16", I never knew that. I just knew it was smaller than 1/2" and larger than the 1/4" which made it perfect for table leg mortises. I usually clean out the mortises with a LN 1/4" mortise chisel just because I don't worry about braking it and because it doesn't really need to be that sharp. Today I wanted a sharp chisel, in other words a bench chisel to clean up the ends of the mortise. Lot of luck bubba, out of the hundred or so bench chisel on the walls of the shop there is not one 5/16" chisel. As luck would have it the new Pfeil chisels I bought the other day had a 8mm in the set. 8mm is just a thin red one larger than 5/16"so all was not lost but damn you would think out of all those chisel there would be a couple of 5/16" ones somewhere. But no joy.

Off to Mexico tomorrow AM for a couple or three days of beer, beach, tacos, and watching the dogs swim and grin from floppy ear to floppy ear. It doesn't get much better.



  1. I am amazed that among all those chisels there is not a single 5/16" one. Please post a complete inventory for our comments. BTW, you have the same Lee Valley mallet I do. How do you like it? It seems a tad heavy to me.


  2. oh surprises, the 5/16 chisel is the most often used size in furniture if you use 3/4 in thick stock. If you don't have a 5/16 bevel chisel, modify one slightly wider (EG Metric) As you find out it is not a common size... :-(

    Have fun on the beach, try to grin ear to ear wider than the the dogs :-)

    Bob, who can finally breathe from both nostrils this AM

  3. Andy,

    After trying to find one online, either 5/16" or 8mm, I've figured out why there isn't one in the chisel racks. The only two I could find were LN and Pfeil. Even the Japanese don't make 'em and/or the sellers do not stock 'em. BTW, LOL my making an inventory of the chisels....Oh look squirrels.

    It is, I usually choke up on it when chopping. I also use a Vaughn nylon face hammer and a Wood Is Good 32 oz. Of the three I use the Vaughn more often because it is lighter than the others.


  4. Bob,

    Like I posted, I pay little attention to sizes. I just look for a chisel that fits and the 5/16"/8mm size fits. Strange to have a mortise chisel but not a bench chisel....go figure.

    Glad the cold is going away. I've master the grin, it's the tongue hanging out the side I can't do. :-)