Thursday, November 21, 2013

Intro to the Festool MFT

At the heart of how they work, power tools are all more or less the same thing: A motor, a rotary shaft, and something that cuts in a rotary motion. The band saw and jig saw are notable exceptions, and the lathe is basically the same process, but backwards, spinning the work instead of the cutter. But regardless of whether it's a router, shaper, circ saw, table saw, chop saw, drill press, milling machine, bench grinder, horizontal slot mortiser, Festool domino, or surface grinder... it's all rotary motion. The primary difference is in how the work is held, and how the work and cutter are presented to each other. It's all about the shape of the cutter, and how you to present the material to the cutter. And presenting the material is what jigs are for.

There are three primary components in any jig that I can think of: The first is a way to position the material in the jig, the second is a way to secure the material in that position, and the third is a way to accurately guide the material and the cutter past each other. A failure in any of these three things results in bad work. If the material isn't properly aligned, the cut won't be either. If the material has room to move around, the cut will move around, too. And if the motion isn't rigidly directed, the cut won't necessarily travel along the intended path. Which brings me to the Festool MFT, a work table that's been really making me re-think a few things.

The surface is an MDF top that's been perforated with a grid of CNC-drilled, 20 mm holes. There are three main components: The table itself, which is covered in mounting points, the fence, which aligns the material, and the track, which guides a tool. (circ saw, router, jigsaw) The fence can be mounted vertically, or flat to the table. The track is held in position at both ends, by mounting points that are height adjustable, to accommodate a variety of stock. Basically, the MFT is a big, modular jig. The main difference between this, and other stationary tools, is that the material is fixed in place, and the tool is moving, instead of the other way around.

For those unfamiliar with the Festool track saw, the edge of the track is a strip of rubbery plastic that gets cut by the saw on the first pass. Because of this, the user can simply cut to a line by laying the rail down on that line, and using the saw. Using the fence, or some dogs, the user can accurately cut a quick 90 degree angle on the table without needing to lay out anything more than a quick pencil tick on the edge of the board, to indicate where the cut needs to be. If you need to make repeated cuts, the stop on the fence will serve.

In hand-tool terms, this set-up is not too far removed from a bench hook, or a shooting board.

That's the beginning. Enter the after-market parts.

The green things here are Qwas dogs. Steve Adams has been making these things for a couple of years now, after a lot of conversations that took place on the Festool Owner's Group forum. His methods of work evolved around using the holes in the top as a way to accurately align and position the work, as well as the major components of the table. Paul Marcel details some pretty straightforward ways to calibrate, or re-calibrate the table components on his blog, and on YouTube, using the Qwas dogs. There are also rail dogs and mini rail dogs, for positioning the fence, or guide rail, or other things, using nothing more than the holes in the table surface. The dogs themselves can also serve as quick-use guides in lieu of a fence, at 90 degrees to the guide rail, or 45, or a few other angles, as allowed by the hole pattern in the surface.

Because I'm using the MFT as an out-feed table, I don't want to have to set up the protractor head and stock fence every time I want to use it. So, I bought some of Steve's rail dogs to hold an alternate fence in place, made of a piece of 80/20 extrusion. So, rather than taking a lot of time setting everything up and calibrating, I can just drop the fence in place when I need it, and lift it off when I don't. In theory, with the rail dogs, you don't really need much more than a top with holes drilled in it, the saw track, and a fence.

Qwas rail dogs, and a chunk of 80/20 extrusion
The MFT excels at quick, one-shot cross-cutting, and repeatable production work. It's also much easier to calibrate, or re-calibrate, than my table saw sled. It won't handle rip cuts as well as the table saw does, but it may be the beginning of the end for my need to do cross-cuts on the table saw.

I have other ideas in mind besides just using it for cross-cuts. But that's a story for another day.

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