Mortising Jig - My Version

  • Advertise with us
Project by Sawdustonmyshoulder posted 06-29-2009 04:16 AM 11923 views 45 times favorited 11 comments Add to Favorites Watch

I always wanted to a jig for making loose or slip-tenon mortises and I didn’t have $800 laying around for one, so like true a Lumberjock, I set out to make one.

I wanted a jig for production work so I tried to make the jig easy to use and incorporate features that make repeatable cuts. I didn’t want a lot of c-clamps or a multitude of tedious alignments.

After much research on Lumberjocks and YouTube, I came up with my version. I won’t say “my design” because I really didn’t design it. I found Kent Shepard’s jig on LJ ( and I really liked the way he designed the front bar to hold the stile (horizontally) but I couldn’t see how he held the rail (vertically). I also liked the way Kent’s jig held the stile without a c-clamp. I also like Kent’s design of the part that limits the length of the mortise and I have to confess, I was too lazy to incorporate this design, so I had to look elsewhere for inspiration for the “router sled”.

The basic design for the “router sled” came from a YouTube video ( The only change I made to this design was to have my rail fixed and make adjustments from the top side of the sled with slots and knobs.

I guess the only things I can claim as mine (they are mine because I haven’t run across them in my research, fair enough?) are: (1) the blocks on the front of the jig to aid in holding the horizontal bar in place while it clamps the rails and also serving as stops to square the rail to the top of the jig. These blocks are adjustable with slots cut in the front of the jig. (2) the grooves cut in the router sled to align the router bit with the center of the mortise.

The basic materials used are 3/4” birch plywood, 1” Red Oak, black walnut runner, 3 – 5/16 knobs, 5 – 1/4” knobs, 2 – 1/4” thumbscrews, dual track from Rockler, plastic cutting board, rubber washers, several carriage bolts and pocket screws.

Thanks for viewing my latest project.

-- The more skilled you are at something, the worse you are at it when someone is watching.

11 comments so far

View a1Jim's profile


118296 posts in 4860 days

#1 posted 06-29-2009 04:19 AM

thats a beauty well done


View Christopher's profile


576 posts in 5203 days

#2 posted 06-29-2009 04:53 AM

Very nice. I will email you my address and you can mail it here first thing Monday! Can you give a quick rundown on how it works?

View Karson's profile


35279 posts in 5684 days

#3 posted 06-29-2009 05:11 AM

A great designed jig. Very nice.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

View jockmike2's profile


10635 posts in 5530 days

#4 posted 06-29-2009 09:19 AM

Great looking jig. Looks like it will work like a dream.

-- (You just have to please the man in the Mirror) Mike from Michigan -

View Sawdustonmyshoulder's profile


489 posts in 4911 days

#5 posted 06-29-2009 02:23 PM

Thanks all for you kind remarks and questions.

Christopher, I am going to work on a blog for instruction on use. May be fun making a video. Wow, I could be a video star!!! Not likely. Let me work on some refinements before I release it to the public.

DaveR, the cutting board doesn’t flex when I plunge. I guess because the cut is supported by the work piece and the router is positioned on the “sled” so the left knob (plunge lever) are over the jig table and not hanging out over the work piece. I usually put just a little more pressure on the left knob. I could add a couple of L-shaped additions to the horizontal bar to run up to the top edge of the work piece to add support. Got to buy more knobs.

I did initially put a washer on the trailing edge of the hardwood runner to catch in the T-slot of the track but I removed it after running into the fact that once the limiting washer was positioned, I couldn’t remove the router from the jig.

-- The more skilled you are at something, the worse you are at it when someone is watching.

View jim1953's profile


2744 posts in 5125 days

#6 posted 06-29-2009 02:42 PM

Nice Jig

-- Jim, Kentucky

View Kent Shepherd's profile

Kent Shepherd

2718 posts in 4569 days

#7 posted 06-29-2009 03:14 PM

Great job——Nice improvements

By the way, I don’t use mine for the the rail. I use a tenoning jig on my table saw.
I like the way you incorporated that into you jig. I bet everything works well. Very good build.
I flattered you use my concept.——-Thanks


View Splinterman's profile


23074 posts in 4645 days

#8 posted 06-29-2009 03:47 PM

Now that is a nice jig…..well done.

View Richard44's profile


10 posts in 4666 days

#9 posted 06-30-2009 03:33 PM

My next project.. thanks for the info

View Bruiser's profile


3 posts in 4570 days

#10 posted 06-30-2009 08:30 PM

Nice Jig, looking forward to your video an would like to see sa plan if possible

View Beginningwoodworker's profile


13345 posts in 4956 days

#11 posted 04-22-2011 05:11 PM

Nice jig.

Have your say...

You must be signed in to post the comments.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics