Problems cutting Mortise/Tenon joins

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Forum topic by Willeh posted 02-06-2012 05:30 PM 2080 views 0 times favorited 6 replies Add to Favorites Watch
View Willeh's profile


228 posts in 2577 days

02-06-2012 05:30 PM

Topic tags/keywords: question walnut chisel joining

Good Morning Folks,

Relatively new to the art of hand cutting mortise and tenon joins. First few worked without a hitch and i thought I was getting a knack for it, however the last two i kept experiencing the same problem. I marked out the mortise, then started chiseling it out and about halfway through (Making a through join), I whacked the chisel and the whole piece of stock split, breaking off the end across the mortise. Working with walnut.

Is this just part of the nature of this wood, or, is this happening because i’m trying to go too deep on a pass, or does this mean i need to sharpen up the chisel again?
Any input is welcome,


-- Will, Ontario Canada. "I can do fast, cheap and good, but you can only pick two... "

6 replies so far

View RockyTopScott's profile


1186 posts in 3716 days

#1 posted 02-06-2012 05:39 PM

Consider drilling out some of the waste first with a sharp bit. Sharpening the chisel never hurts.

-- “When you want to help people, you tell them the truth. When you want to help yourself, you tell them what they want to hear.” ― Thomas Sowell

View HorizontalMike's profile


7770 posts in 3151 days

#2 posted 02-06-2012 05:40 PM

In my limited experience hand-cutting through M&T I did notice that you really need to work the mortise from both sides of the mortise in order to avoid splitting out the exit of the mortise. And chisels can never be too sharp. Just my 2-cents..

-- HorizontalMike -- "Woodpeckers understand..."

View handyrandyrc's profile


33 posts in 2542 days

#3 posted 02-06-2012 06:33 PM

Yeah, while I really wanted to do the whole “I did this project COMPLETELY by hand” thing, I realized there is a much better way to do it. I used a Forstner bit and drill press to hog it out first, then trim the rest by hand.

If you have a bit and brace, you could do it that way, and still be able to say you did the whole thing without electric machines. :)

View stefang's profile


16209 posts in 3572 days

#4 posted 02-06-2012 06:40 PM

H-Mike is right. You need to work the mortise from both sides. I suggest you mark-up the mortise and then using a small drill bit, say 1/8” drill, or the smallest drill you have that is long enough, drill all the way through at each of the four inside corners of the mortise. This should ideally be done in a drill press or some other way to insure that the holes are at 90degrees. Now you have the corners accurately marked out on both sides of your mortise and you just have to draw the connecting lines. Working from both sides also prevents blowout on the underside. Good luck. I did a blog on hand cutting a mortise you might find interesting.

-- Mike, an American living in Norway.

View BerBer5985's profile


445 posts in 2658 days

#5 posted 02-06-2012 06:52 PM

Check out and maybe think about getting his DVDs. He goes very into depth with mortise and tenon joints, dovetail joints, and housing dado joints all by hand. You have to work both sides but you need to be sensitive with the sound of the chisel. When you’re hitting your chisel and the sound changes to a dead sound, you’ve gone far enough and it’s time to move along. It’s hard to explain. He may have a free video on the website. I tried one for the first time last night and it turned out better than expected using that method.

-- Greg, Owner, Quality Carpet One,

View Loren's profile


10477 posts in 3885 days

#6 posted 02-06-2012 06:54 PM

Mortises near the end of a component are best cut before the
final crosscut is made. Leave 2 or 3” of extra wood there
to prevent splitting, then cut it off after the mortise is
cut. Not needed when machine-cutting mortises, though
when drilling and chiseling it still might be a good idea to
leave some extra.

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