How Do You Chop Wide Mortises

[JohnM Martin]

I've been working on a project that calls for 1" wide mortises. I don't own a lot of tools, and I'm pretty new to woodworking so the intuitive thing to do is go out and look for a 1" wide mortise chisel. However, I cant seem to find any that are made that wide. The only reason I can come up with is that pounding a 1"+ wide chisel through hardwood may take a lot of force? After searching the web and finding a couple of different approaches, I thought I'd ask here. What would be the preferred way to chop 1" wide mortises? I do see that you can purchase framing chisels that wide and of course bench chisels but wasn't sure if either of these were the best option.

One method I've seen online was to drill out most of the waist using a drill press then pair along the mortise walls using a bench chisel to square it up. Is that an acceptable method or does that open the door to accidentally widening the mortises by pairing along the walls?

Please help a newbie out.

[Robert Engel]

One method I've seen online was to drill out most of the waist using a drill press then pair along the mortise walls using a bench chisel to square it up. Is that an acceptable method or does that open the door to accidentally widening the mortises by pairing along the walls?

Please help a newbie out.

Use of a pairing block will ensure a straight, square wall and prevent widening.

[lowell holmes]

You can chop that mortise with a 1" bevel edge chisel.

https://paulsellers.com/2012/07/chop...chisels-video/

There are some on this forum that do not particularly like Paul. I took classes from Paul and
I can tell you his methods absolutely work.

I've chopped many 3/4" and 1" wide mortises with sharp bevel edge chisels.

You also can drill most of the wood out and square the edges with bevel edge chisel.

[James Pallas]

I would probably drill and pare. I have cut twin 3/8 mortises with a mortise chisel then cut out the middle. And I have cut them with a bench chisel. All methods work, drilling and paring is possibly a little faster but not much because you still have to deal with a paring block to get the walls clean and straight.
Jim

[Jerry Olexa]

Bevel edge but carefully..Measure first

[Jim Koepke]

Mortise chisels larger than 1/2" are not common. For larger mortises what are often called timber framing chisels are used.

My question would be why such a large mortise?

If you will be doing a lot of these, then getting a large chisel might be a good idea.

If it will be a one time project then learning how to drill and pare may be a better approach.

One of my projects was to make a mallet of ash. My 1" bench chisels just didn't work as well as experience taught me a heavier chisel would. A friend's estate among other things left me an old beat up timber framing chisel. It was rehabilitated and worked much better than a standard bench chisel.

When cutting larger mortises it helps to have a piece of scrap trimmed to the intended tenon size for use as a gauge while cutting the mortise.

Here is a post on my big chisel rehab odyssey:

http://www.sawmillcreek.org/showthre...-For-Mortising

As with many procedures in woodworking there are many ways to get to the same end.

For some drilling and paring a mortise is the preferred method. For others whacking a chisel through a large hunk of wood is like driving a fine tuned racing machine.

jtk

[William Fretwell]

Drill with 1" drill & chop out with 3/4" chisel to start. The holes act as a guide. I do it often, works just fine. Use a 1/4" chisel in the corners to start.

[Joe A Faulkner]

I'd struggle with precision using a 1" drill for 1" wide mortises, so I'd use a 7/8" bit and then clean up with paring or bench chisels. I've also done it the hard way - multiple passes with a chisel that is narrower than the mortise. For me, I feel it is faster to drill then pare than it is to chop everything, but YMMV.

[William Fretwell]

I love the 1" drill for precision. The drill hole at the side of the mortise is a very precise guide for paring, you pare down between the holes until just a sliver of the drill hole is left. It works brilliantly.

[Warren Mickley]

What ever you do, mark both mortise and tenon with the same mortise gauge and cut to the line for fit and efficiency.

Generally we use different methods for mortises that are over 1/2 inch than we do for those under 1/2. Mortise chisels are most efficient for these small sizes. However one can use the same mortise technique for a larger mortise using a wider chisel.

More commonly if the mortise does not need great precision we bore holes and then chop out the remaining waste. For precision mortises I like to mark out the mortise with the gauge and make a 1/4 mortise along each gauge line, then chop out the center with a chisel like 5/8 or 3/4.

[Roger Nair]

A have spent years as a restoration carpenter and in the case of mortised locksets, the mortise is first rough drilled and finished with a chisel. Practically speaking a wide mortise in seasoned hardwood-stress on hard-drilling seems to me to be the best option. Wider yet in green wood, 19th century timber frames were roughed out with a hand cranked boring machine with a depth stop or by a tee auger for the more modestly equipped carpenter.

[JohnM Martin]

What ever you do, mark both mortise and tenon with the same mortise gauge and cut to the line for fit and efficiency.

Generally we use different methods for mortises that are over 1/2 inch than we do for those under 1/2. Mortise chisels are most efficient for these small sizes. However one can use the same mortise technique for a larger mortise using a wider chisel.

More commonly if the mortise does not need great precision we bore holes and then chop out the remaining waste. For precision mortises I like to mark out the mortise with the gauge and make a 1/4 mortise along each gauge line, then chop out the center with a chisel like 5/8 or 3/4.

Thanks for summing it up. Learned something today.

[lowell holmes]

I needed a 15/16" mortise for the through arm mortise on a rocking chair.

I took an old bevel edge chisel, ground it to 15/16" width. I then used it to chop the through mortises on a chair I made for my first great grand child (grand daughter) to be rocked in. I still have the chisel and often use it. I still have 1" wide chisels.

[david charlesworth]

A method We used on a hollow chisel morticer, was to cut 1/4" or 3/8" slots down either long side and then remove the middle.

Worked very well on some 1 1/4" through mortices in hard African timber.

These were used in my bench design.

best wishes,
David

[Peter Gee]

To expand slightly on David's suggestion, you can do much the same using hand tools by chopping out two trenches to the full mortise width, taking care to leave a central spine, which can be removed later. It is important to make two separate trenches so that the chisel doesn't wander over, making the side walls slope. You can use a small mortice chisel for the trenches as the trenches themselves will act to define the side walls of the finished mortise - as well as making that initial chopping much easier and quicker, of course.

In bocca al lupo.