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Hand Chopping A Mortise Tutorial

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Blog entry by stefang posted 10-23-2009 09:22 PM 23930 reads 20 times favorited 67 comments Add to Favorites Watch

I described how to hand chop a mortise in a recent comment. Another LJ member asked if I would do a blog with photos on it. I learned this technique some years ago from an article in Woodworker’s Journal by Ian Kirby a master English woodworker who immigrated to the U.S.A. Some time ago. His method is quick and accurate.

I hand chop mortises when I have so few to do that it isn’t worth the effort of setting up my mortiser attachment to my combination woodworking machine and/or when I have real long clumsy pieces that aren’t easy to clamp onto my mortising table. For those who use routers for mortising, you might want to hand chop when you don’t have a bit that is long enough to do the depth of mortise you desire.

Here is what you need to do the job. Please note that I have used a bench chisel with beveled side edges on the blade. A better choice would be a mortise chisel which is thicker and without beveled blade edges. However, they are hard to find in Norway, and expense. The bench chisel works pretty good, but you will just have find it’s limitations through experience.

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The first thing is to select a chisel that will be the same width of your mortise. This is important unless you want to use a lot of time chopping and shaving the sides of the mortise.

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Here I am making the first cut. Note that the flat side of the chisel is facing the middle of the mortise. Keep the chisel vertical. When you strike it the bevel will make the chisel cut in the direction of the mortise center line.

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Here I’m making the 2nd cut from the other end of the mortise. The chisel has been again positioned with the flat side towards the middle.

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This is the result of the first cut. You have to lever he chips out with the chisel’s bevel and the hole edge acting as the fulcrum.

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Repeating the sequence of the first cut gives the results of the 2nd cut. The board has been turned around end for end, Looks a little confusing, sorry.

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After the 3rd cut.

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After the 4th cut. Note that I stopped about 1/16” short of the end lines. This way you don’t ruin the finished edges while levering the chips out.

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Now the mortise ends are being chopped vertical to prepare for the fine chopping to the end lines.The idea is that when you chop to the line there will be so little material left that you won’t have to lever it out and ruin your nice fresh ends.

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Final Chopping or the mortise ends and some cleanup on the bottom and the corners. You will probably notice that there are levering marks on one end of the mortise. I put those there to show what happens if you lever against the end edges(LOL). If you have done a good job of holding your chisel straight while striking it you won’t have to do much on the sides. If you are a little incompetent like me you might have to take a few shavings there as well. This is not a fine woodworking mortise, but it isn’t too bad either. I had to do a fast and dirty job on this today due to a few small catastrophes. My computer router went out late in the day and had to be replaced. and I also wasted a lot of time on a scrollsaw job that I messed up and have to do over again. In other words, just a normal day at my house. I haven’t been scroll sawing lately, so I guess I really need some practice as I have gone from bad to worse.

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Marking up for the tenon.

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The tenon marked out. It’s length is about 1-3/4”, a little under the depth of the mortise.

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Quick freehand cut on the bandsaw (not particularly recommended).

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Trial fit. Not too bad, the tenon needs a little shaving. I like to cut the tenon a little oversize so I can make sure to get a good fit with small adjustments.

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Ok. Here’s the final joint. Ignore the lever marks on the one end of the mortise. YOU are not allowed to do this!

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A proper tenon should have a shoulder on the ends too, but I didn’t bother with it for this blog. Granted this is not Fine Woodworking Magazine quality appearance, but I’ve been doing it for some years. I hand chopped mortises into the wall supports for my timber rack which is pine, and I have been storing quite a lot of weight on it’s 3 shelves for 7 or 8 years and the shelf supports which are tenoned into wall supports are just as solid as when I joined them.

Well, another windy blog. For you old hands who can do it better than me and wonder why I have put so many words and photos in, I just want the novice woodworkers who are interested to get the whole lowdown. I remember when I started out there was always some essential info missing which made me go wrong more than once, so I wanted to cover it as well as I could.

Thanks for reading this. If even only one woodworker gets some good out of it I will consider it worth the effort.

-- Mike, an American living in Norway.



67 comments so far

View stefang's profile

stefang

13054 posts in 1992 days


#1 posted 10-23-2009 09:28 PM

My pleasure notottoman. I changed one wrong picture out. It was the results of the 3rd cut. I hope you find it useful.

-- Mike, an American living in Norway.

View HokieMojo's profile

HokieMojo

2101 posts in 2385 days


#2 posted 10-23-2009 09:55 PM

stefang. what about the sides of the mortise. Do you pare them out with a chisel? I assume they need to be smooth but that they won’t be just from chopping right? Just wondering. I’ve never cut a mortise by hand before. thanks for the tutorial.

EDIT: I think i missed it the first time. sounds like paring is not necessary.

View mtkate's profile

mtkate

2049 posts in 1983 days


#3 posted 10-23-2009 10:14 PM

Nice demo! I am sure some LJs who have never done this before will benefit from the step by step. I know it was a mystery to me the first time I did it.

View stefang's profile

stefang

13054 posts in 1992 days


#4 posted 10-23-2009 10:20 PM

Hey HokieMojo. If you do it well enough you will not have to shave the sides. This requires keeping the chisel square to the hole. Sometimes while chopping I get a little off square and then the sides need a little paring.

-- Mike, an American living in Norway.

View a1Jim's profile

a1Jim

112104 posts in 2234 days


#5 posted 10-23-2009 10:42 PM

good blog

-- http://artisticwoodstudio.com Custom furniture

View Scott Bryan's profile

Scott Bryan

27251 posts in 2479 days


#6 posted 10-23-2009 11:28 PM

Thanks, Mike. This was a pretty informative blog. You demonstrated the mortising technique well.

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

View Jim Bertelson's profile

Jim Bertelson

3664 posts in 1822 days


#7 posted 10-24-2009 12:17 AM

Thanks Mike,

I have never made a mortise of any kind, so this was very useful. Nice to know you really don’t have to have a machine.

I am chugging away on my benchtop downdraft table. Meaning, you set it on or clamp it to a bench. Down to pegging screw holes, filling some nail holes, and then the finishing. Hopefully will be able to apply finish tomorrow, display Sunday, but don’t hold your breath. Worked about 4 hours, but then my eternal infernal back infirmity gets the best of me and I have to rest. Born with the problem, but age has made it worse. Did get all the holes drilled, most of the screws pegged, and the panels with holes edge routed. This is classified a utilitariian project, and I want it to be sturdy, durable, and flexible. Built from plywood, some leftovers, some oak salvage for spreaders.

Now I am just hanging out baby sitting my bird…............

-- Jim, Anchorage Alaska

View Jimi_C's profile

Jimi_C

507 posts in 1892 days


#8 posted 10-24-2009 02:44 AM

The main question I have about this is, how do you gauge the depth of the mortise while chiseling? It looks like you’re going as deep as you want on the first and second cuts, and then the rest are all referenced off those, I just wanted to be sure that’s how you’re doing it.

-- The difference between being defeated and admitting defeat is what makes all the difference in the world - Upton Sinclair, "The Jungle"

View Chips's profile (online now)

Chips

199 posts in 2370 days


#9 posted 10-24-2009 02:57 AM

Thanks Mike! Got to try this.

-- Make every day the best day of your life. Chips, Mississippi

View nmkidd's profile

nmkidd

758 posts in 1830 days


#10 posted 10-24-2009 05:59 AM

Thanks for the great show and tell.

-- Doug, New Mexico.......the only stupid question is one that is never asked!........don't fix it, if it ain't broke!

View stefang's profile

stefang

13054 posts in 1992 days


#11 posted 10-24-2009 10:59 AM

Thanks for the positive comments all.

Jimi I didn’t pre-plan the depth on this one. I forgot to mention that you can mark the depth on your chisel with a piece of masking tape. Sorry, I was a little frustrated and hurried yesterday and I see now that I missed some details.

-- Mike, an American living in Norway.

View Jimi_C's profile

Jimi_C

507 posts in 1892 days


#12 posted 10-24-2009 04:36 PM

No worries, I think we got the gist of it :)

-- The difference between being defeated and admitting defeat is what makes all the difference in the world - Upton Sinclair, "The Jungle"

View TopamaxSurvivor's profile

TopamaxSurvivor

14753 posts in 2333 days


#13 posted 10-28-2009 08:53 AM

Nice job Mike!! Sorry to be late, I was shooting a match in Oregon over the weekend.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View TopamaxSurvivor's profile

TopamaxSurvivor

14753 posts in 2333 days


#14 posted 10-28-2009 08:55 AM

BTW, Any one interested in hand mortising can find mortising chisels on ebay. They’re on there all the tiime.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View stefang's profile

stefang

13054 posts in 1992 days


#15 posted 10-28-2009 10:58 AM

Thanks Bob. Good tip the mortise chisels available on ebay. I see you are active in the shooting world. The Norwegians are very active in this sport. A short time ago we hosted the Norwegian championships here in our little community of 13,000. A Norwegian just won an international title, but I’m not sure which nations were competing as I don’t really follow the sport. They always have the national competition on TV here in Norway. I went shooting with a friend at work once back in 1981 to a competition range. We used rifles they had there. I was amazed at how heavy they were, much heavier than an M1 for example and I found it very uncomfortable. I was raised with 30/30 lever action rifles which I feel a lot more at home with.

-- Mike, an American living in Norway.

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