I am happy to say that the new approach appears to work. I borrowed an idea that Jerry Work documented in his manual about the Festool Multi-Fence System Multi-Routing Template (which I will reference using the acronym MFS).
Jerry described how to make multiple saw cuts and I simply used the same setup to route multiple parallel grooves.
I will not go into all the details covered by Jerry but will show the set-up and briefly describe it: (1)
Four MFS fences (two 40cm and two 70 cm)
have been joined to make a rigid and very accurate rectangle. Another MFS fence (1 metre long), which I will call the reference fence, has been loosely attached to the outside set of holes in a Festool Multi-Function Table (MFT) using two regular Festool clamps inserted through holes and into the slot in the bottom of the fence then tightened from below the table. (2)
The rectangle has been aligned to the edge of the MFT guiderail making use of the straight oak board then it is temporarily clamped into position.(3)
As shown in the picture below that I extracted from Jerry's manual, markers are put at 30cm point on both scales. Then these points are aligned and the reference fence is clamped down tight. (4)
The clamp is removed from the rectangle.
Now the set-up is complete and precision swing and/or routing can commence. The distance that the 30cm mark on the rectangle is moved to the left of the 30 cm mark on the reference fence is the distance that the right-hand edge of the rectangle is from the right-hand edge of the guide rail.
One moves the rectangle to the desired location, clamps it down, places the wood to be sawn or routed tight to the rectangle, clamps it down, lowers the guide rail, then saws or routes. Of course, if you are routing, it is also necessary to compensate for the distance from the guide rail to the router bit. In the case of the work I am about to show below, a test showed that the distance from the right-hand edge of the guide rail to the right-hand edge of the routed groove was exactly 5 centimetres.
In the picture below, I am routing a set of parallel groves the right hand side each being 21 milimetres from the right hand side of its neighbour.
In the photo below you can see where I have marked the 21 mm increments on the rectangle scale with a soft pencil.That's all for now folks -but keep watching this space to see if I end up being able to make a decent pen box for Isla.