How come my hand cut mortis holes are so sloppy?

[Alex Gauthier]

Looking for some specific technique pointers, I guess.

I'm trying to use bench chisels to cut them which works ok, I'm using a mortis gauge and marking knife to layout the holes first. I carefully start at one end, making a shallow cut and work my way across the length of the mortis cutting deeper until I get to the far end. I don't trim or clean the walls as I work but I tend to have pretty "fuzzy" holes and the final product isn't consistently wide. I'm using the width of my chisel to set the width of the mortis. Does this just boil down to practice or are there little tricks to make it go faster and more accurately?

[Nick Stokes]

Be very cognizant and careful with your chisel placement on the first strike, all the way down. Pay attention to the holding your chisel vertical as well as you make that first strike... if you are tilted, you will chop down under the line, which will leave a jagged edge.

One solution is to use a paul sellers style mortise guide. works great for maintaining vertical. Can also be used to substitute marking out the mortise if you want to be clever about it.

But absolutely with practice your mortises look cleaner. Good thing they're hidden. I would suggest chopping mortises first, so that if you bugger them up, you can just cut a fatter tenon, and trim to fit.

Don't believe the guys that tell your their mortises are always perfect, square, with smooth edges...

[Prashun Patel]

1. A mortise chisel with straight sides helps keep the walls smoother.
2. Yes, it boils down to practice. For all chisel work, I find it comes down to your ability to work up to a line, and antipating how far the chisel will move away from bevel with each strike. The sharper your chisel, and the more precise and deep your knife marks, the easier it becomes. However, once your eye and hands improve, it becomes quite straightforward.

PRACTICE!

[Alex Gauthier]

Hmm, I think I'm trying to do what you suggest. So I must just need to try harder, or pay closer attention. Luckily, I thought to cut the mortis first so there's that. Also, mine are meeting in the middle somewhat accurately which I'm grateful for.

I had to google the mortis guide you describe but that looks worth a shot as well so thanks for that tip!

[Brian Holcombe]

Bench chisels are not great for mortising. Use a mortise chisel.

In addition to that, lots of practice, I cut a good number of mortises before I could get to the point where I chop them by hand without much paring work, but it was worth it.

Don't bother with a guide or other gimmickry, just practice. When you know it's vertical by your eye you'll chop a mortise in a reasonable amount of time and make a nice looking mortise. If you need to rely on guides you'll find that the process takes forever and that the results are so so for any number of reasons...the guide moved, the chisel moved off the guide, etc, etc.

[Jim Koepke]

Hi Alex, what Nick says is correct.

My addition is to not start at the end. Start in a bit and save the ends for last. This keeps the ends crisp and free from the effects of levering out the waste.

As to the fuzziness of the side walls that is seen even if using a chisel made specifically for cutting a mortise (mortis or mortice depending on native spellings ).

Depending on what chisels you have at your command you can use the thickest flat sided chisel of the correct size to help a bit. Also you can start with a slightly smaller chisel and use a wide paring chisel to smooth the sides.

It is true a bench chisel can cut a mortise. The geometry of a mortise chisel (pig sticker) aids in keeping the chisel on path and lessens the fuzziness of the side walls.

jtk

[Pat Barry]

Is your chisel sharp? Really sharp? If not or not sure then sharpen it. Have you tried to drill out much / most of the waste first or are you just chopping away? Bulk removal should be done with an auger or drill - it can really make the job easier. How much practice / experience have you had?Don't set your expectations too high until you are working to refine your technique, not just learn it. What type of wood are you chopping? Is this new and different than material you've had success with before? Some woods are much friendlier than others to work with. Are you chopping into face grain or edge grain or end grain? It can be a whole 'nother process depending on grain - you need to adapt to the situation at hand and this comes from experience.

[Bill McDermott]

Nick, For most mortises, the fuzzyness does not matter thanks to a shoulder that is fatter, allowing joint inspectors to flatter. Sorry.
Bench chisels twist and catch. Mortise chisels stay parallel, due to their thickness. That does help a lot.
The pound down and then thrust forward actions cut across the grain when the edge is slicing down and then with the grain as the face/sides of the chisel are shearing forward (or back). Mortise chisels make that easier and more effective than bench chisels.
For what it's worth, I know exactly what you are going through. Very same learning curve here. Practice does make a difference. A light, precision cut at the top, followed by surprisingly powerful blows once you are into it is not natural until after you have arrived there. They go faster and look better with practice. Try different woods. That also makes a big difference.
Chopping mortises is cool, eh?

[Simon MacGowen]

Bulk removal should be done with an auger or drill - it can really make the job easier. How much practice / experience have you had?.

As a teacher of mortise & tenon classes, I must disagree with the suggestion that drilling away the waste would help a beginner trying to do M&T joinery. It is more difficult for beginners to place their chisels on a partially drilled surface. Also, it is a myth that super sharp chisels are needed for mortising work. One would constantly try to sharp one's tool edge than spend time on chopping as the tool edge would dull quickly when working with hard wood, like oak or maple. Reasonably sharp is all that is needed.

For practice, start with a thinner scrap, say, 1/2" thick and then work your way up after you are happy with the practice results. If you get poor results with, say, a 2" block, go back and practice. If you learn mortising by trying to cut a through mortise on a 4" thick block, you are asking for frustrations.

Simon

[Alex Gauthier]

Good info above, thanks all. I guess I will try it with a mortis chisel even though I've been trying to do it the Paul Sellers way with just bench chisels. I have cut others in thinner material (with varying degrees of success). So far, everything I have cut holds together fine once glued and others were tight enough that glue seemed like overkill. I'm building a workbench at this point and the legs are indeed about 4" thick so it's a pretty large jump in thickness. I have all weekend to practice so hopefully then I'll have it reasonably dialed in. Then I can work on making straight cuts with a panel saw!

As a teacher of mortise & tenon classes, I must disagree with the suggestion that drilling away the waste would help a beginner trying to do M&T joinery. It is more difficult for beginners to place their chisels on a partially drilled surface. Also, it is a myth that super sharp chisels are needed for mortising work. One would constantly try to sharp one's tool edge than spend time on chopping as the tool edge would dull quickly when working with hard wood, like oak or maple. Reasonably sharp is all that is needed.

For practice, start with a thinner scrap, say, 1/2" thick and then work your way up after you are happy with the practice results. If you get poor results with, say, a 2" block, go back and practice. If you learn mortising by trying to cut a through mortise on a 4" thick block, you are asking for frustrations.

Simon

[William Fretwell]

I had two splendid mortising chisels before they were stolen. They do make the task easier, especially with a sharp corner. You do need to start carefully, cut down along the scribed lines on the long sides then chisel out from 3/4 or more of the mortise backwards. That gives you a steady method and stance for a large part of the mortise. A mortising chisel can twist in the mortise and guarantee the mortise will be too wide, hence starting carefully. With practice you will be surprised how hard you end up whacking the chisel after the mortise is started.
For very large mortises, beyond your mortise chisels, drilling out the waste can help speed things up, especially in difficult woods.

Keeping the sides parallel and straight takes practice, but when they are, you can trim the tenon to fit tightly. Practise with a good wood such as cherry, money well spent as you will learn faster.

[David Eisenhauer]

Everything they have said about going straight "freehand" and using a mortise chisel is good advice. Paul Sellers could probably build anything with a bench chisel and a #4, but I need all the advantage I can come up with. I chop mine with my body positioned behind the chisel on the long side of the mortise so that I can visually confirm/correct my "east/west" alignment and rely on feel to achieve a vertical "north/south" alignment. For whatever reason, I have always been fairly able to come up with "plumb" by feel. I concentrate on the initial positioning of the chisel tip to be square across the mortise, just kissing the mortise lines, take a smallish bite, and then easy strikes (mostly hammer weight) to the chisel that fall directly down to the top of the chisel. As I recall, two strikes usually does it before I hear the sound of a bottoming out chisel. In other words, I don't allow my hammer strikes to cause me to slightly twist or otherwise move the top of the chisel. I don't try to achieve maximum depth on each blow, just work on alignment and let the depth come as it will. The depth comes quicker than one might think at any rate. I can't recall having to pare sidewalls on typical furniture-sized mortises but do so if I have drilled out deeper/larger mortises as in a bench build. I don't drill out furniture sized mortises, but others may very well do so with great success. Sharp at 35* bevel works best for me. It will get easier fairly soon. Now sawing on the other hand................

[Nicholas Lawrence]

As a teacher of mortise & tenon classes, I must disagree with the suggestion that drilling away the waste would help a beginner trying to do M&T joinery. It is more difficult for beginners to place their chisels on a partially drilled surface. Also, it is a myth that super sharp chisels are needed for mortising work. One would constantly try to sharp one's tool edge than spend time on chopping as the tool edge would dull quickly when working with hard wood, like oak or maple. Reasonably sharp is all that is needed.
Simon

I don't teach beginners (or anybody else), but I get good results without drilling. Paul Sellers has a decent video on how to chop a mortise without drilling, and I found it to be pretty helpful. It took a couple of tries to get the method down, but once you figure it out, the work goes very quickly. I think he has it posted on his YouTube site, where you can watch it for free.

ETA: Here is the video I found helpful.

https://www.youtube.com/watch?v=q_NXq7_TILA

[Paul Sidener]

There a lot of ways to chop a mortise. People use them because they all will work, some better than others. I agree with what others have said, use a mortise chisel and practice. This video might help you too. Jeff Miller is a furniture maker in Chicago, and has a good way to clean up the walls. I have seen him do this in his shop, when he hosted Lie Nielsen Tool Event. Sometimes the simple way is to add a step. His way works and doesn't add much time. It will give you the cleanest walls

[Joel Thomas Runyan]

Use a proper mortise chisel, as others have said; and strive to use the straightest grained stock available. If you are trying to cut a straight and square mortise in a piece that does not have straight and parallel grain, it will fight you, and has good reasons for doing so.