Mortising jig V2 (WIP)

[Phil Thien]

You guys may remember my mortising jig project:

http://www.jpthien.com/mj.htm

It works great but I really wanted something a little more flexible, where I could use other routers and vary the size of the mortise.

So I'm back to making a unit that will use a 5/8" O.D. bushing and a template/fence with four different size slots. It works pretty well but the shortest slot is a problem because the vacuum holes in the sub-bases I've tried can't clear the mortise during machining. I've got a DW611PK and a DW618 with plunge base and have the same issue with both.

So I'll have to upsize the shortest slot by 1/4" I suppose. With the four different slots, and the ability to use 1/4", 3/8", and 1/2" router bits, you can get twelve different length mortises, from about 1-1/8" by 1/4" up to 2-5/8" by 1/2".

So I'll redesign and change the slot lengths. I really don't need that short a mortise, increasing the length 1/4" isn't a problem. Now I have to put more thought into slot lengths, any suggestions? Looking for flexibility.

The project is drawn in AutoSketch and cut with a CNC router I built from parts I got here and there.

The jig produces really terrific results using the other three slots, I get nice flush faces.

Now I just need to wait until I can get more funds for more 3/8" BB plywood, I'm completely out. My kid required some stuff for school so all my woodworking budget (so much for budgeting) went into that, LOL. Maybe I'll list the two I've got on eBay with an explanation that the short slot isn't ideal, and see if I can get enough money for another piece of plywood.

The fence design is pretty clever, if I say so myself. The first pic below shows one of the templates on a large fence that gets clamped into my woodworking vise. Then you just clamp your workpiece to that fence. The shorter fences allow me to just hold the wood and the template together and then squeeze the entire thing in my vise, it goes very quickly.

[Chris Fournier]

That looks like it will be a very servicable jig Phil. I made something like it some years ago but in the end I found that dedicated one offs for a given joint were better for me. I have had a slot mortiser for several years now and it really has taken over this sort of jig in my shop but every now and then there is an awkward set up that cries out for a jig like you have shown and off I go reliving my past. A router is only limited by the ingenuity of its owner, looks like you and your router bring out the best in each other!

[Phil Thien]

That looks like it will be a very servicable jig Phil. I made something like it some years ago but in the end I found that dedicated one offs for a given joint were better for me. I have had a slot mortiser for several years now and it really has taken over this sort of jig in my shop but every now and then there is an awkward set up that cries out for a jig like you have shown and off I go reliving my past. A router is only limited by the ingenuity of its owner, looks like you and your router bring out the best in each other!

Funny you mention that because before I went this direction I thought of making a slot mortiser. But I really wanted something small (doweling jig sized) that would allow me to do mortises.

[Phil Thien]

As noted, the dust extraction on V2's shortest slot wasn't great. So now I've eliminated the two shorter slots and replaced them with holes for doweling. So V3 is now a doweling/mortising jig.

The holes are spaced 3/4" center to center. The row with four holes and two slots was designed for 3-1/4" wide "dressed" two-by-fours (which I often use for work tables, tool stands, etc.). The slots provide a method to edge reference the 3-1/4" workpieces. It works way better than I thought it would, I can just eyeball it and get alignments as good as any doweling jig I've used.

I'm plunging the holes with my router, using a 3/8" spiral upcut bit. My current bit has a 1/2" shank, which limits depth to about 1-1/4", which is fine for most of what I do.

The plunge-action on many routers is very linear, and my DeWalt is no exception. I was surprised on my first test joint just how easily the joint slid together. Way, way better than any drill-bit based dowel jig I've ever tried.

It is also amazing how fast I can plunge holes, and the dust collection on the router is a welcome feature, too.

[Prashun Patel]

Elegant and versatile. You are the best, Phil.