Help w/thru mortise

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Forum topic by Juan1066 posted 03-11-2012 11:46 PM 1267 views 0 times favorited 12 replies Add to Favorites Watch
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6 posts in 1958 days

03-11-2012 11:46 PM

I was hoping that someone would be able to give me info on whats the easiest way to make this kind of mortise and tenon joint. I don’t have a mortising machine and will primarily be doing this w/hand tools. I have attempted them a couple of times, but everything seems to be a little off, or at times I get chippout on the back side. There has to be a easier way(i hope). Anyone know of any video references out there? I have looked on this site for something that would show the process, but have not had luck. Well, any info would be greatly appreciated. Thks

12 replies so far

View ShaneA's profile


6417 posts in 2017 days

#1 posted 03-11-2012 11:52 PM

Are you going half way thru, then flipping over and coming in from the other side? Should stop the chip out.

View ksSlim's profile


1203 posts in 2308 days

#2 posted 03-11-2012 11:53 PM

Remove most of material with drill bit using backer block. Clean up sides and ends half way thru from both sides using chisels. Drill press and forsner bits are prefered at my place. Super sharp chisels make it easy.

-- Sawdust and shavings are therapeutic

View Loren's profile


8158 posts in 3066 days

#3 posted 03-12-2012 12:23 AM

Mark it out on both sides. Lacking a mortise chisel
you’ll struggle to chop straight mortises by hand.
A mortise chisel and a good bench helps the work
go smooth and accurately.

Mortising with chisels isn’t a hard skill to learn but
there is a sense of the gravitational feel of plumb
you can train yourself into. A tri-square placed on
bench with the ruler part sticking straight up can
be helpful in learning this feel.

Of course doing some amount of drilling out the
waste is another way to go about it. If you
have a drill press, perpendicular holes are
easy to drill.

View Juan1066's profile


6 posts in 1958 days

#4 posted 03-12-2012 12:38 AM

Thks for all the info everyone. I will give it a shot.

View HorizontalMike's profile


7063 posts in 2333 days

#5 posted 03-12-2012 01:20 AM

Don’t forget to be patient. You tend to blow out the mortise if you get too aggressive. Take your time, it will come. Sneak up on the fit. IMO, it should take a while before the tenon will be able to fit the mortise. Too quick and you could over-shoot.

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

View Tootles's profile


779 posts in 1920 days

#6 posted 03-12-2012 11:32 AM

Remember that the shoulder of the tenon will cover the mortice on one side. So if there is to be any chance of blow out, aim for it to be on that side of the mortice.

-- I may have lost my marbles, but I still have my love of woodworking

View Marlow's profile


116 posts in 2090 days

#7 posted 03-12-2012 11:46 AM

I’ve only made this joint with a router, but if you cut half-way through on one side, then flip the piece over and cut the opposite side using a bit like this, you will get a perfect copy of the front side mortise. Need to drill an opening from the back side to start the cut.

View Juan1066's profile


6 posts in 1958 days

#8 posted 03-12-2012 02:40 PM

wow, thks for all the responses. What a great site.

View dbray45's profile


3147 posts in 2195 days

#9 posted 03-12-2012 03:07 PM

A lot of people when they start out drilling and chiselling holes through a piece of woord clamp it in a vise a go to it.

Always drill or cut with the piece clamped to a sacrificial piece of wood. This eliminates the blowout when you go throug the wood into the sacrificial piece.

-- David in Damascus, MD

View canadianchips's profile


2307 posts in 2416 days

#10 posted 03-12-2012 04:04 PM

Cut your MORTISE first ! If it is off a bit it is easier to make a tenon that fits than it is to make a MORTISE to FIT the TENON.
When chiseling a mortise begin with smaller then mortise needs to be (INSIDE your MARK) after you are through you can sneak up to the desired line you want.

-- "My mission in life - make everyone smile !"

View HalDougherty's profile


1820 posts in 2656 days

#11 posted 03-12-2012 04:29 PM

This maple bench project I made a while ago has a photo of the jig I use to cut mortises. I make the jig the thickness and width of the leg I’m using and use a router pattern bit to finish opening the mortise after I drill out some holes to get rid of the waste.

Click for details

I’ve cut mortises several different ways and with practice you can make a good joint with almost any of the techniques.

-- Hal, Tennessee

View dbray45's profile


3147 posts in 2195 days

#12 posted 03-12-2012 05:07 PM

Hal – if you were to cut the mortise at a little angle at the narrow two ends, about 1/8” wider at the top, and put a wedge in the tenon about a 1/4” in to fill the gap, the bench would stay tighter longer and give it a cool look as well. I have done this with good results

-- David in Damascus, MD

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