Horizontal Mortising Router Jig

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Project by WoodenSoldier posted 03-21-2011 04:38 AM 6732 views 19 times favorited 10 comments Add to Favorites Watch

Lately I keep starting projects and then reaching some unforeseen obstacle and putting the project to the side. I’m probably working on a total of 6 different things in the basement (does anybody else have this problem?) This weekend I actually started and completed something for a change! It felt pretty good too.

This is a horizontal router for mortise cuts, especially useful in end grain. I used one of these in a woodworking class I took and I couldn’t believe how easy it made the process.
A few weeks ago I started a small dog bed and stopped when I realized I had no reliable or easy way to cut the mortises in the rails so I decided to build one of these.
I had an extra router, and I sheared and machined a piece of 1/4 aluminum at work for the plate. Finished it in one weekend! I made the base a little proud so that I can clamp it to my router table and then I plug it into the same switch.
Unfortunately I was so excited that after testing it I decided to try the dog bed project again and I mortised the wrong piece! Oh well, I can make another rail.
I didn’t have any plans, I just looked at a couple of other ones on Lumberjocks.

I’m probably going to add some stop blocks, dust collection and measuring tape. I’ll post pictures when I do.
Thanks for looking!

-- Create something everyday.

10 comments so far

View Routerisstillmyname's profile


763 posts in 4046 days

#1 posted 03-21-2011 05:11 AM

Looks good. Still need to decide on the size of the router bit hole.

-- Router รจ ancora il mio nome.

View 489tad's profile


3663 posts in 3549 days

#2 posted 03-21-2011 02:26 PM

Thats nice, good job.

-- Dan, Naperville IL, I.G.N.

View SPalm's profile


5334 posts in 4419 days

#3 posted 03-21-2011 02:43 PM

Hey WS, it’s looking good. I love these kind of projects.

I have a couple of things that you could think about should you want to. One thing that always bugs me (like the riser rod of my thickness sander) is the backlash in turning the screw. I see two different leadscrew nuts in your pictures, so maybe you have seen this some (?). Anyway, a nice way to produce a lead screw nut is to thread your own through a bar of plastic (or even a hard wood), maybe an inch tall. The screw will be tight to turn, have no slop, and it also gives you an easy way to mount it by drilling through the sides. Much easier than using a T-nut or trying to weld a nut to a plate.

Another thing is the ability to mount some stop blocks. Routers have a way of grabbing a work piece and having their way with it. So a simple T-track or even overhang the top on the sides a little bit so you can use clamps and scraps of wood. If you ever do make a new top, add a couple of stiffeners, like a floor joist, to keep that particle board from sagging over time.

Anyway, it looks really nice. Compact and useful too.

-- -- I'm no rocket surgeon

View steliart's profile


2895 posts in 3225 days

#4 posted 03-21-2011 05:46 PM

very nice jig, i love it

-- Stelios L.A. Stavrinides: - I am not so rich to buy cheap tools, but... necessity is the mother of inventions !!!

View bobkberg's profile


439 posts in 3610 days

#5 posted 03-21-2011 05:50 PM

Very nice! Sometimes a good tooling piece is more satisfying than a project.

-- Bob - A sideline, not how I earn a living

View eruby's profile


79 posts in 3312 days

#6 posted 03-21-2011 11:02 PM

Very nice,
I have one of these somewhere on my to do list.

why do you have the quick clamps on the vertical piece?

-- Eric - Baltimore MD

View WoodenSoldier's profile


161 posts in 3482 days

#7 posted 03-22-2011 06:53 AM

That’s everybody.
Steve, I’m not sure what exactly you mean by back-lash. I guess I’ll have to play with it a little more to see if I notice any. I deliberately picked all thread with a very fine threading so that it would give me better adjustments with the knob.
As far as additions to it, I think I will definitely add a T-track and some stop blocks soon. You can see in the last picture I used quick-clamps as stop blocks.
I hadn’t thought about bracing the top, but maybe I should do that soon before it’s too late. I liked having the little space there to store the sled though.

-- Create something everyday.

View Sarit's profile


551 posts in 3677 days

#8 posted 03-22-2011 11:20 AM

SPalm, I believe the threaded rod is only for positioning the router before you start cutting. The mortise is made by sliding the workpiece horizontally by hand. Therefore the backlash shouldn’t be an issue with this design.

FYI, backlash is essentially the play between the nut and the threaded rod. When you reverse the direction that you turn the rod, you want the linear motion to also reverse immediately. In things like CNC machines, they must be eliminated.

WoodenSoldier, it might be helpful to draw or scribe a center line on the plate so that you can see where the bit is when its buried into a workpiece. This will allow you to mortise pieces that are wider than the table.

View SPalm's profile


5334 posts in 4419 days

#9 posted 03-22-2011 02:25 PM

Hey guys, I really am not trying to be too picky here, but this is what I meant. As Sarit says, backlash is the play when you reverse directions of the threaded rod. A lot of time it is not just the threads inside the nut, but how the nut is attached, and how the rod is attached to the router. I see that you have two twist nuts to lock the plate in its final position, so once locked, it does not matter. But you want the mortise to be precisely placed in the up/down direction. You will probably do this by trial and error on a piece of scrap. So you will raise it up a little, try a cut, oops too high, lower it a little, oops, etc. Having that little slop might screw up (pun) what you think a quarter turn will do. No biggy, just something to watch out for.

Also the “tap your own leadnut through a block” type nut is a lot easier to mount securly than trying to capture a standard nut in a block of wood with plates, friction, epoxy, etc.

But what you have done looks great and I bet it will work just fine.

-- -- I'm no rocket surgeon

View bigike's profile


4057 posts in 3826 days

#10 posted 04-24-2011 03:41 AM


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

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