# New DIY Mortising Jig



## WoodBrewer (Mar 4, 2009)

Thought you all might like this. Pics posted below in my reply.
TPro Mortising Jig:

I decided to build a custom mortising jig recently. I really like loose tenon joinery as its strong and to me easier than traditional mortise and tenons. As always, money for WW (at my place) is in short supply. So, buying a Festool Domino is not in my foreseeable future. More importantly, I’m a gadgeteer that really enjoys designing and building jigs & tools.
Over the past few years I’ve made many of the diy mortising jigs in the books and on the internet and haven’t been totally pleased with the results. So, I decided to build my own version. I may have overdone it a bit this time but it was fun and I think I’m set for now.

PICTURES:
1. Front view of jig with a piece of 1×4 pine installed and ready to mortise.
2. Back side showing router edge guide and top plate that router base slides on. 
3. Side view – see hardwood block attached to edge guide that runs in a slot also incra T-Track Plus and Stop blocks.
4. Work Piece Hold Down Fixture – removed from jig
5. Fixed plate – attaches to base of jig by 2 holes at top that have 5/16 brass threaded inserts installed. Back side of jig has holes for bolts to attach this plate. Dados indexes the slider plate (next photo).
6. Slider plate with hardboard guide that runs in the grooved of the fixed plate. Note: this plate does not need the dado that runs 90 degrees from the hardboard guide.

FEATURES:
Uses a plunge router loaded with spiral upcut bits. A guide rail slides in a groove on the backside of the jig. I use PC 690 with a plunge base, PC Edge Guide, and 1/4”, 3/8” and 1/2” carbide upcut router bits. 
With this jig the full length of the bit can be used for deeper mortising capability than some other jigs allow. INCRA T-Trak plus permits the lateral stops to be precisely indexed for perfect length mortises. 
The larger size of this jig makes for easy mortising setup for small and large work pieces alike. On hindsight a smaller version might be just fine. 
Large vertical base plate and vertical slider plate (18” square each) remove for easier storage. 
Jig top plate is made from a scrap of Corian solid surface material. It’s dimensionally stable and the router base plate slides very easily on it (and it looks cool to me). A piece of 3/4” plywood would work just as well as a top surface.
The Jig’s base clamping “wings” extend 2 1/2” on each end to permit easy clamping to a workbench. Note: a bench vice and dogs could be used to secure the jig as well. 
This Jig is not overly complex to build with normal shop tools (although there are plans for far easier jigs you can build out there).

BENEFITS:
The jig base is easily clamped to a work bench. 
Repeatable cuts in successive work pieces is a breeze following a few procedural guidelines.
Lateral stops (to limit router travel side to side) very easily set.
A hold down clamp’s is adjusted to permit assorted work piece thicknesses to be easily clamped tight near their centers. It is mounted on 3/4” thick piece of plywood and slides up (or down) to adjust where the clamping pressure is put on the work piece. 
Ability to cut mortises on the edge of a board as well as on the ends. 
Capability to easily cut mortises on a mitered 45 end (to be developed later). 
No additional base plate is needed to be attached to the router (only an edge guide). 
Can be set on a shelf or hung up when not being used (both face plates remove for storage).
Amazingly fast, accurate, clean, and repeatable mortises.

Cut procedures to follow; but my “hunt and peck” keyboard style leaves me weary for now.
No plans drawn up yet, but you would need to adjust for your router base and edge guide anyway.
Hope you like it.


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## dutchman 46 (May 23, 2007)

Very nice. Is the jig one that you designed? If you post it here, My guess is that there will be a lot of them around.


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## allthunbs (Jun 22, 2008)

Hi TJ: Nicely done. I see a bunch of uses for a setup like this, mortices, hinge pockets to mention a few but I'm trying to figure out which is a better method, guided like yours or guide bushings. I'm hoping your experience will guide me.

Allthunbs


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## AxlMyk (Jun 13, 2006)

Nice jig.
To post a picture, Click New Reply then scroll down till you see Manage Attachments. Click on one of the browse buttons, choose your picture, then click upload. Finish your message and you're done.


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## WoodBrewer (Mar 4, 2009)

Ok; thanks for the info on how to post pics here directly.
Here are a few of the jig.

Yes; it's mostly my design. The slider plate and guide track I got from a nother jig plan (but these aren't unique anyway). 

The reason I didnt want a guide bushings mortise jig (although easier to build) is it must ride on top of a plate that will reduce the depth that the bit can plunge into the work piece. That might be solved with long bits though. YMMV.


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## WoodBrewer (Mar 4, 2009)

allthunbs said:


> I see a bunch of uses for a setup like this, mortices, hinge pockets to mention a few
> Allthunbs


Gadzooks! I hadn't even thought of using this jig for hinge pockets. I am a box builder and have avoided those hinge types due to the complexity (at least to me) of getting them right! Now it will be downright easy. Thank you for the brain spark.


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## dovetail_65 (Jan 22, 2008)

WoodBrewer said:


> Ok; thanks for the info on how to post pics here directly.
> Here are a few of the jig.
> 
> Yes; it's mostly my design. The slider plate and guide track I got from a nother jig plan (but these aren't unique anyway).
> ...


Sweet jig WoodBrewer!


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## Ralph Barker (Dec 15, 2008)

Nice setup, TJ. It took me a few seconds to see the strategy of your design, but I like it. Using the edge guide to establish the ends of the mortise with stop blocks also adds more stability, too, I'd think - rather like an outrigger on a boat.

Do you have (hidden) guide rails on the bottom support to keep it (mostly) square?


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## WoodBrewer (Mar 4, 2009)

Ralph;
Yes there is a harboard guide that assures the slider plate that the workpiece rests on is square for both horiz. and vertical mortising operations.

Pics to help.


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## lmk (Oct 29, 2008)

Wow...this looks great and it looks fun to make. You mentioned that repetitive mortises are easy to create... what is your technique for doing so? For example, how would you cut several mortises in two sides of four table legs?

Thanks.


LMK


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## kolias (Dec 26, 2008)

Beautiful work TJ, that's what I needed

Nicolas


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## WoodBrewer (Mar 4, 2009)

lmk said:


> You mentioned that repetitive mortises are easy to create... what is your technique for doing so? For example, how would you cut several mortises in two sides of four table legs?
> LMK


Good question. 

I'll try to describe what I think the procedure is for cutting the 8 moritises needed for typical table legs. I don't have a lot of experience with this jig yet so take this all with a "grain of salt". Please feel free to add steps/revisions/comments.

IMPORTANT: This is only a guide about how I think I will do it. Follow all the normal safety guidelines listed in your power tools instructions. Safety is no accident! 

Carefully and clearly mark the 2 mortises needed on one table leg. Mark the outside of the mortises as well as the center of the mortices (both vertically and horizontally). One will be left side and on will be right side. If the mortises are not centered on the table legs mark the "lefts" and the "rights" on all the legs clearly. We will assume they are not centered on the table leg. Lets proceed to do the left side mortises.

Be sure the jig is securely clamped to benchtop. 

Put the router and guide assembly aside (off and unplugged). 

Set the T-Trak stop blocks for desired mortise length by using the ruler on the Incra t-trak plus. The hardwood runner (attached to the router's edge guide) is 7 inches long. So, by adding 1" out on each side from (3 1/2" to 4 1/2") will make a mortise 2" in length. Note: the ruler on T-Track reads out from zero on both sides making this a simple procedure. 

Adjust the hold down clamp bolt for stock thickness tighten nut and black knob. If available a short piece of scrap (the same thickness as the table leg) will make this an easier task. 

Set the workpiece horizontally atop the front slider plate. Adjust the slider plate (vertically) so the top edge of the workpiece is even with the Corian top plate. Note: if the mortise is not in the center of the table leg, it should positioned with the mortise closest to the jig. In other words - don't make the cut of the mortises overhang the jig more than it has to. 

Adjust the horizontal position of the leg so the center mark on the table leg and the center line on the Corian top plate line up. 

Adjust the hold downs plywood slider plate so it positions the clamp near center of the workpiece. Tighten the 2 knobs on the hold down slider plate and press the hold down lever to secure the workpiece to the jig.

Clamp a stop block to the left of the workpiece (to index for the other leftside table leg cuts). 

Set the router on the top plate with the hardwood edge guide runner in the slot on the back side of the jig. 

Set the routers edge guide laterally to position the router bit on the workpiece and your layout lines. With the router off (and unplugged) test plunge the router to ensure the bit is aligned with the work piece layout lines. 
Secure the edge guides lockdown bolts/knobs.

Set the router plunge depth. 

Mortises are ready to be cut. Plug in and turn the router on. Slide the router to the right until it hits the stop. Plunge the router to max depth keeping the routers plate firmly on the jigs Corian top plate. Unplunge the router an slide the router to the left side and repeat.

Plunge again about 1/8" moving from left to right across the workpiece removing waste. On subsequent plunges take about 3/16" and move from left to right continueing to remove the waste until the mortise is complete. 

Stop the router and set aside.

Unclamp the workpiece from the hold down.

Blow out any sawdust and wood chips from the edge guide runners track and in front of the stop block.

Repeat for the 3 other leftside table leg mortises using the stop block to index.

Unclamp the stop block scrap and reposition on the right side following the above setup procedure.

Cut the 4 rightside mortises.


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## Belg (Nov 2, 2011)

Tj, I'm looking to make myself a mortise jig and am wondering how this has worked for you? Any changes, threw it away and started with something else kind of things thanks Pat


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## TwoSkies57 (Feb 23, 2009)

Pat...

just a heads up. It doesn't look like TJ has posted in here since 3/2009. You might try his email. Right click on his name and use the drop down menu to access an email address. Have no way of telling if its still a valid address..but you can give it a try


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## Belg (Nov 2, 2011)

Bill, thanks a lot for the info. The post above mine was made on 03-23-2009 still a long time ago, lol. Will give the email thing a try.


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## TwoSkies57 (Feb 23, 2009)

OPS.. *L* my bad,,, date corrected...

your quite welcome Pat... good luck with your search..


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