ByronBlack said:
I intend to use the 2m length extrusions and then buy the angle/mitre fence as a seperate item
Personally, I'm not a great fan of the angle/mitre fence, mostly because the angle detents aren't very accurate. Also, if your MFT is 2m long, you're limited in where you can put the angle unit if you still want to be able to use the side extrusion to fasten the left end of the fence. Of course, you can solve that by using a shop-made clamping device, but then you have to figure out some way of being able to replace your fence in the "square" position any time you change the angle or move the fence...and you will be moving the fence often. (Don't ask me how I know this
)
Here's an idea that I'm going to try for the fence of the upcoming 3d incarnation of my 2m MFT--(1) use a Kreg or Incra track for the fence; (2) fasten it near the front of your MFT; (3) align it to be parallel to the front edge of your table top; (4) make reference jigs so that if you remove the fence, you can quickly put it back in the same place, perfectly parallel to the front edge of your table top; and (5) align your guide rail to be perpendicular to the front edge of your table top using the "double error squaring method" taught by Rick Christopherson here
http://home.att.net/~waterfront-woods/Articles/Double-Error-Squaring.html
You can clamp a sacrificial sheet to the top of the MFT underneath the piece you will be cutting during the squaring process--that way, you won't put a wide, ugly kerf in your table top while you're squaring the guide rail to the fence. If you go to Festool's site and download Jerry Work's manual on the MFS (
not MFT), you'll see how he mounts a fence at the front of his MFT. Granted, he uses the Festool angle unit to attach the fence to the table, but you don't have to do that.
This idea of not using Festool's angle unit and fence is related to the issue of laying out the holes in your MFT. First, to clear up any confusion, 20mm diameter and 96mm spacing are the correct dimensions. That said, I've built three large MFT tops, and for the first two I bored the holes with a router just by drawing a grid of lines and eyeballing it. I was able to get all the holes within +/- 1mm of the correct location (i.e., the spacing was never less than 96mm nor more than 98mm). The Festool angle unit will work with hole spacing of about 97-99mm. But the angle unit is the only accessory that uses fixed two studs spaced 96mm apart, so if you don't use the Festool angle unit, then it doesn't matter if your holes are off by a few mm.
In addition to boring the 20mm holes, consider mounting some 1/4-20 or 5/16-18 t-nuts or inserts in the underside of the table top, and drill the holes all the way through so you can screw a bolt in the table top. Why? Because it gets tiresome to reach under the table all the time to fasten the Festool clamping accessories. Bending over and stooping down again and again chips away at your physical and mental freshness, sapping your productivity beyond the time you spend doing it.
You can make some auxiliary fences for sawing and squaring and hold them in place with bolts or cam clamps like these:
http://www.leevalley.com/wood/page.aspx?c=2&cat=1,43455&p=52800
http://www.leevalley.com/wood/page.aspx?c=2&p=45034&cat=1,43455,52799
By the way, I have pics of the shop-made auxiliary fences and some other stuff for the MFT, but I can't post them until Monday, because the file sizes are too big to post on this forum and I don't have photo-editing software here at home. I also posted text and pics on design considerations for large MFTs on the old forum but I never brought it over to this one. For what it's worth, I'll see if I have a copy of the text somewhere.
Finally, after I've spent all this time and text telling you the disadvantages of using the Festool fence and angle unit, send me a PM if you want to buy mine, incl the adjustable stop.
Regards,
John
