Is there a good way to chop mortises squarely?

[Frederick Skelly]

Cut 8 mortises last night with a 1/4" mortise chisel. I had to widen 4 of them and widen the corresponding tenon. Thats shameful, even for a beginner. I think whats happening is that, while Im getting them straight, Im not getting them "square" in the vertical.

Constantly checking with a small square helps, but its tedious and really slows me down. Does anyone have a better technique for keeping them square?

Thanks for your help folks!
Fred

[Brian Holcombe]

Clamp a visual reference to the board and sight it.

[Pat Barry]

Cut 8 mortises last night with a 1/4" mortise chisel. I had to widen 4 of them and widen the corresponding tenon. Thats shameful, even for a beginner. I think whats happening is that, while Im getting them straight, Im not getting them "square" in the vertical.

Constantly checking with a small square helps, but its tedious and really slows me down. Does anyone have a better technique for keeping them square?

Thanks for your help folks!
Fred
How deep were you going Fred? Also, type of wood were you cutting?

[David B. Morris]

I had the same problem the first time I cut mortises by hand. They were over an inch deep and about 3 inches long, and I coinsistently leaned left with the chisel. Brain's suggestion for a visual reference is correct. I clamped a bar clamp onto my bench in line with the workpiece, making sure it was plumb, and that solved the problem. Derek Cohen's excellent tutorial on M&T includes this suggestion as well.

[Mike Henderson]

Drill out the majority of the waste on a drill press and then just clean up the sides with a chisel. The drill press will guarantee that the mortise is square to the face.

Mike

[george wilson]

Practice,practice,practice.

Fine tune the Mk.1 eyeball gauge.

[John Schtrumpf]

In many cases, I clamp the board so it is going lengthwise straight away from me, and sit down to chop so the board is closer to eye height. Then I use the board itself as a reference.

[Kent A Bathurst]

Drill out the majority of the waste on a drill press and then just clean up the sides with a chisel. The drill press will guarantee that the mortise is square to the face.

Mike

But, if you do that, don't you have to turn in your Neander Secret Decoder RIng?

[Chris Hachet]

But, if you do that, don't you have to turn in your Neander Secret Decoder RIng?

Shhh....sometimes I chop mine with a hollow chisel mortice machine and then touch up the mortice with a hand chisel.

[Kent A Bathurst]

Shhh....sometimes I chop mine with a hollow chisel mortice machine and then touch up the mortice with a hand chisel.


Heretic............

[Zach Dillinger]

Practice,practice,practice.

Fine tune the Mk.1 eyeball gauge.

Bears repeating. For effective practice (and as others have suggested) try sighting a try square while chopping. Eventually, if you do it enough, you will develop the muscle memory to do it squarely.

[Frederick Skelly]

How deep were you going Fred? Also, type of wood were you cutting?

9/16" deep, in poplar. Mortise is 1 1/2" long a 1/4" wide.

[Patrick Harper]

It really helps to sight down the length of the mortise as opposed from the side. It doesn't really matter if you undercut the ends of the mortise very much. It really just needs to be tight throughout the thickness.

[Daniel Rode]

Like a lot of had tool woodworking, time and lots of practice lead to a feel for it. I'm not quite there yet but I keep practicing. I had a heck of a time with some small 3/16" x 3/8" deep mortises the other day. I had to toss a piece and start over. Having the piece laying in the right direction helps me as does going slowly and methodically.

Sometimes, when it absolutely positively has to be right, I mill up a nice square block and clamp it to the piece as a guide for the chisel. It'll insure a perfectly straight line and allows me to register the chisel against it for a perfect 90 degrees.

It feels like cheating but sometimes I just don't want to risk ruining the piece for the sake of practice.

[Frederick Skelly]

Thanks guys. Yeah, I know just what youre all saying - it really should be a matter of practice, just like learning to use my planes was. I was looking for these kinds of tips to help me last long enough to get there.

Mike, I'm with you. I was sorely tempted to use the press last night. But Im trying to resist using that just long enough to develop my muscle memory. I may get to using the press long term. I just feel like I should learn to add and subtract before I start using a calculator. (Since Ive never used M&T joinery, this is a chance to start with the basics and move to machinery later if needed.) You tech this stuff, so Im guessing you can relate. On a different matter - I thought of you last night as I used 2 of your "home made" Buck Brothers skewed chisels to finish up some half blind dovetails. THOSE DTs came out pretty well, thanks to your suggestion!

To all of you, thanks for teaching and helping me. I get a great deal of hand tool learning by reading this forum and asking questions.

Merry Christmas to all!

Fred

[Robert Hazelwood]

There are a variety of jigs you could use, from a bar clamp to a square set on the bench, to an actual guide that the chisel's side can rest against. But eventually, you'd like chopping mortises to be a fast, fluid operation...which means you'll need to be able to intuitively feel for square and not rely on jigs. I think at your stage (which is basically my stage as well, I only have about 50 hand chopped mortises under my belt), a good way to go would be to set the chisel on the marked out mortise as though you're going to chop, and eyeball it for square. Now hold the chisel still and grab a square, and check your "eyeball" square against the real one. If it's off, make a note of which direction you need to adjust, lay the square down and re-set the chisel by eye, then grab the square again. Once you've got it right by eye and confirmed with the square, proceed with the chopping (concentrating on maintaining square as you chop and also keeping it from twisting in the mortise). When you reset for the next chop, do the same thing with eyeballing square and checking. I my mind, it's important not to actually set the chisel plumb using the square, but to set it by eye, only using the square to confirm. Eventually you should reach a point where you are normally very accurate by eyeball, so that the square almost always confirms you've set it correctly by eye. That would probably take a while. At that point you could omit the square. The same basic idea can be done with sawing square lines, chiseling dovetail baselines, etc. I try to do this when I have a clear head and am not rushed...I think it has definitely helped some, and I do trust myself more to make an accurate cut, although I still feel the need to use a square on critical work.

Just an idea.

[Harold Burrell]

Shhh....sometimes I chop mine with a hollow chisel mortice machine and then touch up the mortice with a hand chisel.


Heretic............

Stone him!!!

[Jim Koepke]

As George posted, practice, practice and more practice.

Plus calibrating your eye. Robert mentions his 'eye calibration' technique.

For me it is having the work piece clamped and then sighting the length of the work with the sides of the chisel. If the work piece is squared and straight, it can be you reference.

My tenons are usually cut to be tight. If there is an off square lean, one side of the tenon can be pared to true it to square. It usually doesn't take much.

The benefit of taking the time for doing training exercises to calibrate one's eye(s) can not be overly endorsed.

jtk

[ken hatch]

Using a good mortice chisel i.e. an English Bolster chisel aka a pig sticker will help. Then follow George's advice. Like almost any thing, you get better the more you practice.

[Mike Henderson]

Practice,practice,practice.
That reminds me of the story of the stranger in New York City who goes into a subway station and asks a drunk, "What's the best way to get to Carnegie Hall?"

The drunk looks at him hard, tries to focus and says, "Practice, man, Practice!"

Mike

[Jim Matthews]

I took a 9 day course with Paul Sellers.

We used a guide to keep the mortises perpendicular
to the top face, and avoid just the problem you've described.

The natural tendency is to pull the chisel toward your body,
just as you strike with the mallet.

We used what looked like an overlarge "button" for holding tabletops down.


The guide is clamped to the side of the workpiece, and on the knife line for the side of the mortise.

302584

[Stanley Covington]

It may not be the cause, but if the chisel's sides are not square with the flat, or especially if the cutting edge is not square with the blade, it can make it more difficult to keep the mortise square.

Stan

[Zach Dillinger]

Do it whatever way works for you. A better man than me (can't remember who now) once said to me, "Ain't no Merit Badge for hand tool woodwork, man." Might have been T-Mac.

[Mike Holbrook]

Charlesworth "Chisel Techniques for Precision Joinery" uses a wood reference, as tall as the chisel. I think an engineer's/adjustable... square is easier and simpler to position.

[Don Jarvie]

Use a marking gauge to mark the first line on the outside of the piece. Put your chisel against the line and mark the other side and use the marking gauge to scribe that line. Use the marking gauge again to scribe the 2 ends. Take a regular chisel and clear out a bit so you have the mortise then chop away. Once you chopped out the mortise you can square it using some of the techniques others have mentioned. Then make the tenon.

When you make the tenon make sure you use the outside face as your guide so they match up. Use the marking gauge to scribe all of the lines on the tenon then saw away. You may need to pare the tenon to get it to fit snug. One trick is to bevel the inside of the tenon so the outside of the tenon face is slightly higher than the inside.

[Andrew Hughes]

Surprised only Stanley mentions the cutting edge square to the sides of the blade.Maybe the smaller chisels are more forgiving if a bit skew.
I also use a square behind my work to get started.

[Derek Cohen]

The picture tells the story ...

http://www.inthewoodshop.com/Furniture/MorticingByChisel_html_26dd5384.jpg

I may also stand a 12" square alongside the chisel. With these two visual aids you won't go wrong. Within a short time you will develop a sense of vertical.

Tutorial: http://www.inthewoodshop.com/Furniture/MorticingByChisel.html

Regards from Perth

Derek

[Jim Matthews]

I may also stand a 12" square alongside the chisel. With these two visual aids you won't go wrong. Within a short time you will develop a sense of vertical. Regards from Perth Derek

So the upright bar of the F clamp is the visual guide - that's elegant.
I can never fathom how you make so much furniture, yet your
shop is free of the shavings, offcuts and sawdust that makes mine
so inviting, underfoot.

Do you keep a picture of a basement behind a curtain, that looks like a dungeon?

[Frederick Skelly]

Once again, thank you all. I really appreciate all the advise, drawings, photos and tutorials!. Ive got many new ideas to try out and NOW I should be able to get it right.

Best wishes and Merry Christmas!
Fred

[Kees Heiden]

So the upright bar of the F clamp is the visual guide - that's elegant.
I can never fathom how you make so much furniture, yet your
shop is free of the shavings, offcuts and sawdust that makes mine
so inviting, underfoot.

Do you keep a picture of a basement behind a curtain, that looks like a dungeon?

I think you just discovered the truth behind the myth Derek. He isn't actually doing any woodworking himself. There are some hired professionals in the dungeon behind the curtain who do all the work and then Derek displays the items in the staged shop, makes pictures and writes about them.

[Winton Applegate]

Ha, ha I don't have anything constructive to add except to say relax and enjoy your self.

I would encourage you to watch more Roy Underhill Woodwright episodes . . . his rustic results can make you feel pretty good about the fit and finish of your joints.

In the same breath it is probably best TO AVOID watching Frank Klausz cut mortice and tenon joints . . . could cause you to lean toward an enthusiastic bout of hara-kiri.

[Jim Matthews]

I think you just discovered the truth behind the myth Derek. He isn't actually doing any woodworking himself. There are some hired professionals in the dungeon behind the curtain who do all the work and then Derek displays the items in the staged shop, makes pictures and writes about them.

I knew it!


https://www.youtube.com/watch?v=WXh1tW16V-8

[Derek Cohen]

Do you keep a picture of a basement behind a curtain, that looks like a dungeon?

:)

Photoshop is great!

Regards from Perth

Derek

[Adam Cruea]

The picture tells the story ...

http://www.inthewoodshop.com/Furniture/MorticingByChisel_html_26dd5384.jpg

I may also stand a 12" square alongside the chisel. With these two visual aids you won't go wrong. Within a short time you will develop a sense of vertical.

Tutorial: http://www.inthewoodshop.com/Furniture/MorticingByChisel.html

Regards from Perth

Derek

This is what I do, except I use a K-Body Bessey (sometimes two if the piece getting mortised is long).

Also, make sure the edge doing the cutting is perpendicular to the sides (if you have the type of mortise chisel).

By the way, it slightly bears mentioning, if you're a hulk and/or going through particularly dense wood, try to do the chopping over a bench leg. While it's pretty negligible, you'll get a more solid whack out of each swing, and you'll transfer the energy directly down to the cement pad your bench probably sits on.

Not hugely important, but hey. . .

[Derek Cohen]

By the way, it slightly bears mentioning, if you're a hulk and/or going through particularly dense wood, try to do the chopping over a bench leg. While it's pretty negligible, you'll get a more solid whack out of each swing, and you'll transfer the energy directly down to the cement pad your bench probably sits on.

Not hugely important, but hey. . .

Adam, that is important .. and even more so if the bench top is not the thickest - a thinner top may flex.

For those that did not register this from the photo - the chisel is positioned at the centre of the chop of a leg vise ...

Regards from Perth

Derek

[Tom M King]

Have a helper do the holding, that can make adjustments to counter your out of vertical mistakes, especially with $27 bd. ft. boards 20 feet long.

[david charlesworth]

Of course the mortices don't have to be perfect.

If they are glued and clamped, (or pegged), the shoulders will pull up tight.

This puts a slight bend on the tennon, but the glue or pegs will hold a pretty good position. At least this is what happens on furniture scale work.

best wishes,
David

[ken hatch]

Of course the mortices don't have to be perfect.

If they are glued and clamped, (or pegged), the shoulders will pull up tight.

This puts a slight bend on the tennon, but the glue or pegs will hold a pretty good position. At least this is what happens on furniture scale work.

best wishes,
David

Yep, pretty much.....It's one of the reasons I love draw boring, if the shoulders are good the M/T joint will be good. Not an excuse to be sloppy but a pin or two can make up for a lot of errors.

ken

[Michael Ray Smith]

Not if you use a hand-powered drill press. I have an old Millers Falls -- or maybe its Goodell-Pratt. Don't recall at the moment. Not nearly as precise as modern drill presses -- much more runout. But good enough for this purpose. It seems to reduce the wobble some if you use a forstner bit, at least if you have the wood clamped down tightly.

[Michael Ray Smith]

I have the same problem, and I'm still working on that "practice, practice, practice" part. Clamping a straight board or something similar along the edge of the mortise, as others suggested, is the most helpful thing I've tried. I also drill out a lot of the waste, but I use a bit that's smaller than the width of the mortise, but maybe I should try more often with a bit that the same width as the mortise and the side of the drill hole to get the side of the mortise straight. It's also helpful if I sneak up on the edge of the mortise by slicing away the last few millimeters with a paring chisel, a little at a time, rather than just chopping away all the way to the line with a mortise chisel. But that's just me. You mileage may vary.

[Brian Holcombe]

I knew it!


https://www.youtube.com/watch?v=WXh1tW16V-8

And the sacrificial thumb to help legitimize the the story :p

[Winton Applegate]

I am not a big old dog when it comes to M&T but pre drilling the mortises . . .
for me
is a night mare. Paring out the middle the chisel twists unexpectedly one way or other driven by the interaction of the bevel on the sides of the holes. Paring the sides of the mortise with a wide chisel gets more out of hand than just chopping out from scratch (no drilling at all) with a mortising chisel.

My mileage is a flat tire with no spare by the side of the road.

PS: I love my nice floor model drill press and Forstner bits though. I can happily play with those all day.

Oops . . . that was not very Neander of me was it.

[Prashun Patel]

Always looking for a guide and short cut, I've found that the key to straight mortises is indeed tedious practice. My mortises too started out v-ish. After a few, my eyes were able to anticipate what the tenons were going to say about the mortises. My problem is mortising is like drywalling. I get good at it by the last one of the job. By the time the next job starts, I'm rusty.

A guide actually slows me down in mortising.

Also, try a wider chisel. It's easy to set a wider chisel once than a 1/4" chisel vertical many times.