Loose Tenon Mortising Jig - Tested and Improved

  • Advertise with us
Project by Sawdustonmyshoulder posted 03-15-2010 02:38 AM 28570 views 70 times favorited 16 comments Add to Favorites Watch

This is the Loose Tenon Mortising Jig I posted earlier. I did test it and made a few improvements.

The major improvement was the addition of a “rabbeted” piece in the back of the jig (see the second photo) to keep the plastic sled from tipping forward during the cut. I made the rabbet shallow and put a small champfer on the hardwood runner so that I can easily remove the sled between cuts.

Another improvement was to rework the stops by using excess toilet flange bolts that I cut off to about 1 inch long and tighten the stops with brass knobs. These work better than the thumb screws.

I also made a couple of more wooden stops so that I could hold the “clamping rail” up while I made the cuts on the end of pieces.

Making loose tenon joint and lots of them is so easy with this jig. The third photo is some of the mortises I made this week. Cut 144 mortises in about 1 hour and 45 minutes. Lots of sawdust to clean up. Great fun!

I guess my next step is to make a set of plans.

I also spent a little time in front of the video camera and made a short video showing the use of this jig. See the video.

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

16 comments so far

View libraryman's profile


45 posts in 4831 days

#1 posted 03-15-2010 03:34 AM

Looking forward to your plans. I’ve been looking for a jig like this. Great work on the jig and video. Thanks!

View rbterhune's profile


176 posts in 4308 days

#2 posted 03-15-2010 03:49 AM

Ditto…looking forward to the plans.

View HuntleyBill's profile


127 posts in 4176 days

#3 posted 03-15-2010 04:05 AM

I’ll take a set too. Please let us know when they are ready. This jig is fantastic!

-- If you think you can, or think you can't...your right!

View donjoe's profile


1360 posts in 4117 days

#4 posted 03-15-2010 04:52 AM

Great job!

-- Donnie-- listen to the wood.

View bigike's profile


4057 posts in 4375 days

#5 posted 03-15-2010 04:57 AM

nice work

-- Ike, Big Daddies Woodshop, http://[email protected]

View rpete's profile


54 posts in 4101 days

#6 posted 03-15-2010 05:02 AM

+1 on the plans. Great video!

View Julian's profile


884 posts in 4612 days

#7 posted 03-15-2010 12:42 PM

Now that looks like a fun project! I’m with the others on wanting to see some plans.

-- Julian, Homewood, IL

View 559dustdesigns's profile


633 posts in 4254 days

#8 posted 03-15-2010 01:43 PM

This is an ingenious design, thanks for showing it off on video too.

-- Aaron - central California "If you haven't got the time to do it right, when will you find the time to do it over?"

View TJCROSS's profile


165 posts in 4084 days

#9 posted 03-15-2010 07:16 PM

Just the jig is a work of art!


View Sawdustonmyshoulder's profile


489 posts in 4714 days

#10 posted 03-16-2010 02:08 AM

I got a question over on the video blog page that I thought I would transfer over here.

Viking’s question was: Do you make you own tenons or is there a ready source for them? I have several projects that would most likely use 3/8” and 1/2” and possibly 1/4” tenons.

Viking, I make my own tenon stock out of what some call scrap and some call unassigned wood laying around the shop. It helps that I have a drum sander that sands in 1/128th of inch passes so that I can dial it just at the right fit. I round the corners with either a quarter round router bit or a appropriate sized bullnose router bit in my router table.

If I didn’t have the drum sander, I guess I could use the table saw to cut the tenons close and use sandpaper to fine tune the fit. I find that you don’t want the tenons too tight because the glue will swell the walls of the mortise and also the tenon. I am also going to add a saw kerf to the tenons to allow air to escape the mortise and not blow the glue out.

This ability to make your own tenon is really a great feature of loose tenon joinery because you don’t have to spend money on tenon stock or use expensive project wood to make tenons. Over the life of a project like I am working on now with almost 450 tenons at about 1 1/2 inch in stock length per traditional tenon equals about 25 board feet of lumber. And all of the tenons will be made from the stock that is cut off and headed to the trash.

I have some work to do on the chairs tonight but I will start on the SketchUp plans later in the week. I don’t work in the shop on Wednesdays (that’s the wife’s night with me) so I will do some “inside work” on the plans.

Thanks all for the kind comments!

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

View gmerteng's profile


122 posts in 4199 days

#11 posted 03-17-2010 02:00 AM

Great job on the jig, ingenious, cant wait for the plans.

-- Mert,Oshkosh WI,

View JimGo's profile


3 posts in 4071 days

#12 posted 03-24-2010 09:31 PM

This is fantastic, and great timing! I’m just about to do a bunch of mortises (not as many as you!); do you have an ETA for the plans you mentioned? I don’t mean to pressure you, just curious. Otherwise I’ll have to see what I can do on my own (which I doubt will compare favorably!)

-- - Jim

View iminmyshop's profile


379 posts in 3080 days

#13 posted 02-25-2013 05:18 PM

This is the best danged shop made mortising jig I’ve seen. Were plans ever made available to download or buy for this jig?


View tomk807's profile


2 posts in 2755 days

#14 posted 10-31-2013 12:23 AM

This is an excellent looking jig, and just what I have been looking for.
Can I obtain a set of the plans?

TomK in San Juan Capistrano

View tomk807's profile


2 posts in 2755 days

#15 posted 11-07-2013 07:43 PM

If you can e-mail the .skp file from your Sketchup drawing, it would be as good as a set of plans.


showing 1 through 15 of 16 comments

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