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Router Mortising Jig/Fixture

14154 Views 14 Replies 6 Participants Last post by  HorizontalMike
I am in the process of designing/modifying a router mortising jig and after searching on the web and have attempted to build a SketchUp model from a single image of this Mortise Fixture I saw on Garage Woodworks and I am wondering/asking for any and all tips for improving this jig or in using it. FWIW, I overlaid my proposed Mortise Fixture on top of my 21st Century Workbench in the configuration that I built the bench.

++I want to mortise for floating tenons and desire the ability to use this jig for both END mortising and more traditional side mortising. I am thinking I could use my twin screw vise for leg support when mortising the sides.

++ My 2 1/4hp Triton router has a squared off fence attached to the base that will ride against front of jig but haven't figured out how to show that yet. I chose to run the fence on the front because the fence is nearly 2" deep and the jig is just 3/4" thick (3/4" plywood).

++My goals are for only 90degree M&T at this point.

++ Mortise Opening 2"x 6"

Am I missing anything? Better clamp height positioning? One enough?

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The block the clamp is attached to should not go up all the way or
should be removable to allow mortising in the center of a stile or
rail. This design would only be useful for mortising stock a fixed
distance from the stock face. Fine for cabinet doors, but not as
useful for making offset mortises in table legs and things like that.

I've found, with jigs like this, that the one clamp is inadequate and
the work will move when being cut. An additional clamp helps,
but but slow down setups for each cut.

You really need to plan to get a clamp head pretty close to right on
top of where the mortise is being cut. That's why many of these
sorts of jigs have holes in them for clamps.

The frame member will wiggle under cut load from the end mill, so
the solid clamping is pretty important to getting consistent mortise
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MIke I don't know how many mortises you need to cut. But I made one like this several years ago and I love it.
Thanks Leven. I seriously looked at building a Horizontal Mortiser, being the HorizontalMike that I am ;-) but really like the simplicity of a vertical mortiser for the moment (need to get some projects under the belt).

Thanks for pointing out some things I have NOT thought about:

"The block the clamp is attached to should not go up all the way or
should be removable to allow mortising in the center of a stile or
BINGO! Maybe I could just shorten the vertical fence to start just AT the beginning of the mortising opening and use one of my Veritas dog-hole surface clamps to hold the removable vertical clamp/board. That would make this setup more flexible.

"This design would only be useful for mortising stock a fixed distance from the stock face"
This is why I am making the opening 2in wide. I have depth adjustment abilities with the router fence, but just HOW MUCH MAX DEPTH ADJUSTMENT DO I NEED from the edge? 3-inches? 4-inches? Right now I am looking at building rather simple Mission style tables and such… but I am sure I will progress from that sometime in the future.

" clamp is inadequate…"
I'll add a second and use additional furniture clamps if needed.

"You really need to plan to get a clamp head pretty close to right on
top of where the mortise is being cut. "
I am thinking that making the vertical block clamp/board independently anchored to the front of the workbench MAY help me take care of this?
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Hey Steve, I promise to get out your way now that we are both back in-state. If I recall correctly (and that is often questionable), you had been either out-of-state or country and then I followed and spent 2 weeks on the bike riding thru the tornadoes/rain in Arkansas and Tenn on my way to Indiana late April and early May. Today looks poor in that the Hazardous Weather Outlook is calling for some real nasty stuff near home:


That 70mph thing jumped out there and grabbed my attention. We are on the south end of the affected area but who knows.

Anyway, I like the video link. But for starters, I will probably knock out the easy one first and then build the better mouse trap when I can.
I think that Loren is right. You will want some room for Legs, rails, or stiles. I built a jig like this and I use it all the time. I can post some pictures on Sunday if you want to see it. You are right, I like it simple and versatile. I think that you may want to consider trying to get 2 clamps on each board for more security. I only have 1 and I am constantly using a hand clamp to help secure the wood to the jig.

Thanks Tim, it would be nice to see what mods work well. I look forward to seeing them.
Mike, here's a photo of a horizontal mortiser that I made several years ago. I use it mostly for cutting tenons on the ends of long stock, but it works well for mortises too. Very simple and stable. The one that Steve posted looks a little unstable, with too much hardware. It's based on the one in the book "Making classic Joints with power tools" by Yeung Chan
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If you really want to get carried away, look at this.

Also go to his main page. He has some really interesting inventions.
That Pantorouter is something else! Way beyond my abilities at the moment, but WOW!

San Saba huh, ~20yr ago I remember landing my hang glider at the San Saba Airport after flying it some 30miles or so from Packsaddle Mountain near Kingsland, after foot-launching (running off the hillside).

I'll be out there this week.
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Here are some pictures of mine. I built it as a prototype a few years ago and just kept using it. The main difference is that mine uses a fence as the guide on the back and the fence can only move along one axis. With this I can mortise any thickness of stock with any thickness of mortise. It is nice to set up for repeatable mortises. I can clamp stop blocks in the fence track to have identical length mortises. I have even taped 4 degree shims to the face to mortise at different angles. When I make a better one I will improve the clamping. Maybe some t tracks with some type of clamps to go in them. The support wing screws off and it is not needed, but I like that I have it there to clamp things to.
I really debated between this type of jig and one with bushings. If I were to use bushings I would need more jigs for different thickness of stock. I can adjust my fence depth to stock over 3" thick (like bed posts).
I never considered using my bench vice. I may have to try that.
Yours looks good. The one thing I would consider improving is your clamping system. It is the one thing that I don't like about mine. At some point your vertical block that your clamp is on will get in the way. Mine does all the time and it is much smaller. Yours would be nice to have when cuting a mortise in the end of stock but I just use a line to line it up on and that seems to work.



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I'm thinking that 2 - 3 T tracks with some type of quick action clamp is the way to go. I like the toggle clamps, can they be mounted in a T track some how? It would be easier if you were only mortising verticle or only horizontal stock. The key is to get 2 clamps on both types.
Let me know how it goes.

I could make the Pantorouter, but I sure as Hell couldn't Hang Glide
It was one of those balls to the wall kind of things in that my FM radio (walkie talkie) died shortly after launch and my flying partner and our HS student chase driver lost contact with me within the first 5 minutes of the flight. I had borrowed my buddy's radio and he had forgotten to charge it. So before I got to a thousand feet (above the ground) the radio started giving out. I flew the first 10-15 miles by watching my flying buddy's location while working the thermals. Then at roughly the 15 mile mark I had to make a decision to either follow my buddy to the west and follow what he thought was good lift or continue heading north north west in what I thought would pan out (while still being reachable by road via chase driver). I chose to stay my course to the NNW and found a good thermal to work that got me back to 5k or so in altitude. My friend got shot down and landed within 2-3 mile after that and our chase driver picked him up. From that point I was on my own and that second portion of the flight was probably some of the best flying I ever had the opportunity to do.

Normally I would (should I say wood?) work the lift above 5 thousand feet before heading downwind looking for my next thermal (heading NNW), but with no one following me I needed to be more aggressive and would head out earlier at 4,500 feet or less sometimes. I would glide NNW feeling/listening (to my variometer/vertical airspeed indicator) and sometimes got lower than 1,000 feet which was normally a death nil indicator because thermals usually don't kick off below that altitude and you are left scratching out your last glide to landing (in other words looking for a place to land that doesn't have trees, etc.). I remember 3-4 of them before I came up on San Saba. Just south of San Saba I got down to just 900 feet and looking at my watch saw that it was after 5 or 6pm and knew it was late for thermals to still be active. Luckily, I caught what was probably the last thermal of the day just on the south end of town. It was weak, but as I worked it, it took me directly over town and I topped out at nearly 5,500feet above the town with the sun hanging low on the horizon.

My goal had been to try and get to Goldthwaite, TX but that was at least another 20 miles NNE and I couldn't even see it on the horizon. So I started looking around and saw the San Saba Airport. The lift was light but steady at 5,500ft but I started thinking as I looked at the airport,... NO radio, NO water, NO clear goal on the horizon,... so I started circling ever so gently over the airport. I figured the San Saba Airport was as far as I could fly that day and with gentle circles I managed to stay in the air for nearly an hour more, directly over town and the airport before finally landing, not on the airstrip but nearer the airport manager's trailer to the south of the runway (and in the grass). After landing, I unhooked from my glider and walked a couple hundred feet to the trailer and knocked. The gentlemen, a retired sheriff, answered and was amazed that he could not see any motor on my glider. After explaining where I was coming from, he let me call my girlfriend in San Antonio. My flying buddy and I had already arranged to use her as a contact point if and/or when we might lose contact with each other during our flight.

After making contact with the girlfriend, I went back to my glider and started breaking it down and packing it up for transport. Before I could finish with that task my flying buddy and chase driver rolled up at the airport honking and all smiles. They had continued north and had stopped in San Saba to check with my girlfriend in San Antonio, got the message and was nearly at the airport before I got there! It was a great flight that day! And one to remember! I flew nearly 50 miles that day.
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