MFT Router Jig

[JayStPeter]

One of my biggest disappointments with the MFT was using my router on the rail.  I have used simple t-square router jigs such as the one shown for years and still like them better.  The stability of the OF1400 on the rail and the positioning needing an offset just made the MFT less reliable to me.

But, the downside to the simple t-square jigs is repeatability.  They must be positioned for each part and without some sort of stop that is subject to error.  The MFT has the stop, so I decided to use a combination of the two.

I made the jig shown.  I made the top with one adjustable rail so the slot width can be adjusted (more below).

I started with the side pieces.  I mounted them to the rails using standard 1/4" hardware from woodpeckers.  I ran a shallow dado along both the rail support and the table mount and put a thin piece in there to keep the parts sliding in only 1 direction.  Then I cut some slots in the rail support so I can lock in the height with some knobs.  A support that would normally be the "fence" on a t-square jig was mounted to the sliding support and a small piece of t-track embedded to allow one of the top rails to slide.

To use, I mount it to the table.  Unfortunately, the stops for the guide rail keep me from mounting it in an ideal location, but it's good enough.  I drilled some holes through the outer sliding panel that allow me to tighten the mounts underneath.  It takes some effort to get square, similar to squaring the rails.  But, a good square piece of wood underneath helps as you simply align the fixed top rail to the square edge underneath.
Next, using the knobs on the side, I set the height by putting a piece underneath and setting a couple business cards on top.  Then I drop down the rails and tighten them up.  This allows the piece to slide freely underneath without having to worry about flex changing the depth of the dado.  You'll note my version has a knob and a bolt.  I ran out of knobs with short enough threads to avoid the table leg mount underneath.  The inner knobs can be longer since they clear the leg mount.
I then set the width of the slot.  You can use either a piece to set the width:

or use a guide bushing

I've used this thing for numerous operations, strangely almost none of them are what I had intended it for.  There are some things I would (and will have to) change.

First, I made the thing out of scraps.  The materials aren't the ideal solutions and my poplar rails have moved a bit and are no longer straight along the slot.  This will have to be fixed.  I intend to either embed some angle aluminum along the edge, or use some high quality BB ply.
Second, I'd try to modify the mounting so that the stops for the rails don't prevent me from positioning it where I want it.

Thanks for looking, Jay.

 

[mwhafner]

I love the jig, but I haven't experienced the same issues with accuracy with using a guide rail with the router. 

I do have a similar setup for use in creating sliding dovetails.

The solids that you used for the jig is mostly poplar, correct?  A wonderful wood to work with, if you understand it.

 

[JayStPeter]

yeah, the rails that the router rides on are poplar.  Poplar isn't the ideal wood in this application as it moves a little too much.  The edges are no longer perfectly straight and have a real slight bow.  Not severe (maybe 1/32" or so), but enough to render the jig useless for its primary purpose. 

 

[Dave Ronyak]

Jay,

Thanks for posting details of your routing jig.  It is certainly nicely designed.  Why did you feel it necessary to make rather than guiding your router with a Festool Guide Rail?  What problems did you experience with using a router on the Guide Rails as intended by Festool?

RE squaring up your jig, could you use the grid of holes in the MFT top to set your jig parallel to a couple of pegs placeed into the holes?
And a couple more pegs to define a reference fence at 90 degrees to the line defined by the first pair of pegs?

I noted your MFT fence in the photos.  Couldn't you use a large reference square, MFS or right triangle to establish a right angle (90 degrees) between the inside egdes of wooden guides of your jig and the MFT fence?

Also, I never concern myself with removal or relocation of the so-called factory set stops on the side rails of my MFT.  I just reset them wherever they need to be based on wherever I want my cross-cutting Guide Rail to be.  It's easy and quick to re-establish a square relationship between the MFT fence and the Cross-cutting Guide Rail using a reference square or triangle.  With that in mind, you can place your shopmade jig wherever best suits your planned use for it.

Re modifying the jig, or building a new one:  If the top and inside surfaces of the members that contact the bushing and the base of the router were covered with plastic laminate, or made of a very hard wood, life of the jig would be indefinite.

You could insert a couple of short T-headed or hex-headed bolts or elongated nuts or square nuts into the channels in the bottom edges of the MFT side rails and then modify your jig so the base plate is secured from underneath rather than through holes in the side plate.

Dave R.

 

[JayStPeter]

Dave,

First, the jig has the advantage that it can repeadedly do any width dado without having to readjust anything.  I've always liked that about the adjustable width version of the t-square jig.  Second, I've never been a big fan of the footie.  I've seen David dubyas solution and plan on implementing it someday to try out, but just haven't done it.  Finally, I don't like using offsets to do stuff, which is why I like the rail with the saw.  The combination of those things just led me back to my tried and true way using t-square jigs like the first pic. 

Squaring the jig is just like squaring the rail.  I definitely made it sound worse than it is.  I can use the same methods I use to square the rail.  When I use the jig, the part I'm going to rout is usually cut square already and can be used to align the jig instead of a square.  That's basically what I meant to say with that jibberish about squaring that I wrote  : ;D. 

Laminate is a good idea.  I'll keep that in mind when I redo the rails.  The top/bottom mount is also a good idea.  I'm hoping to build a large MFT sometime.  If I do, I might try that out.

 

[John Stevens]

Very nice work, Jay.  Thanks for sharing.

Regards,

John