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Step Stool #6: Hand-Chopping a Mortise (with Video)

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Blog entry by Eric posted 07-21-2008 04:29 AM 2479 reads 1 time favorited 12 comments Add to Favorites Watch
« Part 5: First Hand-Cut Tenon Part 6 of Step Stool series Part 7: I Don't Need No Stinkin' Jigsaw »

After I posted about doing my first hand-cut mortise and tenon, Scott wanted to see how I chopped my mortise. He said, “The only time I tried to chop a mortice I left most of a 1/4” chisel broken off in the wood.” Well, when I read that, I kind of freaked out because I hadn’t considered that I could have broken my blade! But I decided to trust in what I was taught, and to remember that I had, indeed, done one successfully. So I decided to keep at it for my second mortise.

First, I marked out the mortise. I figured out where I wanted it, and then measured the top line with a pencil (exactly 3” down from the base of the pins). I marked that spot with the chisel by pressing it firmly into the wood. After measuring the height of the tenon, I did the same thing on the bottom. Then I connected those outer borders with a marking knife:

mortise 1

I then positioned the chisel slightly in from one of the edges, with the bevel facing the other direction.

mortise 2

Next, I raised the chisel to 90 degrees and gave it a good strike with the mallet. I levered the waste out by lying the chisel down toward the bevel. Here’s a pic:

mortise 3

And here’s the video of me doing it:



After going the whole length of the mortise, I turned the chisel to face the other way and went back, doing the same thing. Then I flipped the board over and started on the other side of the mortise, doing two passes. Before too long I punched through:

mortise 4

At this point, it’s probably safe to hog out the waste by chiseling down the side walls, although I just kept going as I was, ending up with this:

mortise 5

You notice that the side walls need to be cleaned up, and also the length of the mortise extended all the way out to my marked lines. In the next pic, I’ve cleaned up the sides and just needed a little more on the top and bottom.

mortise 6

And there’s my mortise! You can see in the last pic below that it’s far from seamless perfection. But considering that the tenon will be wedged, and that decent-sized dovetails are securing the sides to the top, I don’t think this joint will experience much stress.

mortise 7

Thanks for following along!

-- Eric at http://adventuresinwoodworking.com



12 comments so far

View steveosshop's profile

steveosshop

230 posts in 2322 days


#1 posted 07-21-2008 04:45 AM

Thanx for the video post. I do my mortises in a similiar fashion. Sometimes though on large mortises I bore out some of the waste with a very slow drill or most times a hand auger.

-- Steve-o

View Scott Bryan's profile

Scott Bryan

27251 posts in 2518 days


#2 posted 07-21-2008 12:21 PM

Thanks for the post, Eric. It was informative, straight forward and you presented the process in a clear manner.

Well done.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View PurpLev's profile

PurpLev

8476 posts in 2344 days


#3 posted 07-21-2008 03:09 PM

Nice Post, I’m sure it’ll serve many people!

Thanx.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Betsy's profile

Betsy

2914 posts in 2592 days


#4 posted 07-21-2008 03:20 PM

Thanks Eric. Interesting post.

-- Like a bad penny, I keep coming back!

View Callum Kendall's profile

Callum Kendall

1918 posts in 2399 days


#5 posted 07-21-2008 08:26 PM

Thanks for the video, very intresting!

Tahnks

Callum

-- For wood working podcasts with a twist check out http://thetimberkid.com/

View ChicoWoodnut's profile

ChicoWoodnut

904 posts in 2511 days


#6 posted 07-22-2008 05:15 AM

Thanks for the video Eric! That looks like fun. Now I must explain myself.

When I broke off my chisel I was trying to chop a 1/4” mortise 1” deep in a stile. I had just read all about how to do it in a FWW article. Of course the author of the article was using a nice (and expensive) 1/4” mortise chisel. Magazine in hand and full of foolish enthusiasm I went out to the shop thinking “Who needs one of those fancy mortise chisels. I’m going to try this out with my 1/4” bench chisel”. I pulled out a scrap of white oak from a cabinet I had just finished. The article wanted you to give the chisel a really good whack so that’s what I did. Then I went to “lever” out the waste. Knowing full well that the chisel was made out of hard steel I was a little apprehensive about this move. When I reached the amount of force I thought was deadly to the tool, I stopped and tried to pull it out of the wood. It wasn’t budging. So I figured I would try to rock it out. Rock rock snap dohhh.

This looks like a technique I might attempt again. Since most of my mortise work is for making panels (and thus deeper mortises), I’ll likely either try to be a little more judicious in the severity of my initial whack, or just give in and buy the right tool.

Thanks

-- Scott - Chico California http://chicowoodnut.home.comcast.net

View Roper's profile

Roper

1363 posts in 2409 days


#7 posted 07-22-2008 06:30 AM

scott you will not regret buying a good motising chisel they are the only tool for deep clean mortises. also drilling out some waste is a good idea, makes cleaning out your waste easier. good luck.

-- Roper - Master of sawdust- www.roperwoodturning.com

View Woodshopfreak's profile

Woodshopfreak

389 posts in 2438 days


#8 posted 07-22-2008 09:08 PM

thanks for the video. I have never really heard of levering the chisel to remove the waste. You learn something new every day.

-- Tyler, Illinois

View Dorje's profile

Dorje

1763 posts in 2693 days


#9 posted 07-24-2008 03:06 AM

Nice work Eric. Fun post. Great pics and video.

Are you going to use one wedge or two?

-- Dorje (pronounced "door-jay"), Seattle, WA

View Beginningwoodworker's profile

Beginningwoodworker

13345 posts in 2369 days


#10 posted 07-24-2008 03:34 AM

Nice progress Eric.

-- CJIII Future cabinetmaker

View teenagewoodworker's profile

teenagewoodworker

2727 posts in 2464 days


#11 posted 07-26-2008 08:48 PM

cool eric! i have been practicing hand chopping mortises lately too and i have been doing it that same way. not through mortises though regular ones about 1/4” wide, 1/2” deep, and 1 1/2” long. thanks for the post and the video!

View jeanmarc's profile

jeanmarc

1886 posts in 2412 days


#12 posted 07-27-2008 07:51 AM

Nice work Eric. Fun post.

-- jeanmarc manosque france

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