Having my large boards now jointed and glued, I now need to flatten them. Mulling over the problem in the small hours, I remembered an idea I’d seen in a book on homemade jigs. It’s a very simple idea; just make a gantry across the board that lays flat on the bench and has a slot just wide enough for the widest guide bush I have. The gantry was made from 25mm ply – the 18mm wasn’t quite rigid enough not to dip a tiny bit in the middle under the weight of the router. The jig sits about 5mm above the board and holds the router at the same height relative to the bench, so all I have to do is insert the dish cutter and set it to the right depth to skim the bumps off the top.
At first it didn’t seem to work very well; I tried going along and across and generally scribbling around with the router, but the result was a very uneven surface to which the belt sander was hardly equal. Since this is the ‘wrong’ side of the board it doesn’t matter – it won’t show – so I was undeterred.
I decided to try going across the board, moving the jig a little and coming back across. I got the hang of it quickly enough and did a couple of feet at a time. I let the router cool down while going up the grits with the random orbital sander to smooth the bumps, which were now much more predictable and recognisable. It turns out that I didn’t need the belt sander after all. No bad thing; the ROS is much gentler, even on a coarse grit.
I started with P80, then P120, P180 and finally P240. It took me just over an hour to flatten the whole 2.4m board. A sigh of relief was heaved. I know how to proceed, and I’m confident that it’ll be a good result. The only thing to watch for is the depth stop on the router, which does occasionally slip when I knock it accidentally.
It’s also essential to clamp the corners of the board down on the bench for this job. The flattening is relative to the bench, not the board, so the board has to be flat on the bench. For some boards it will also be necessary to clamp along the sides too; that just means I move the clamps as the jig is brought across. Similarly the corner clamps have to be moved when the jig is brought to each end of the board.
Well, the jointing idea worked, thank goodness. The idea is that you’re not relying on each edge being perfectly straight, you just want the two edges to match each other, so you cut both edges at the same time. That way it doesn’t matter if the guide isn’t perfectly straight. I did, however, try to get it as straight as possible using a piece of thread stretched along it before tightening up the join between the two pieces of the guide.
I was casting around for a suitable spacer for the boards; it makes sense to have them close enough to cut both edges, but sufficiently apart to cut off the minimum amount of wood. The kerf of the saw blade is 2.2mm, and I found that a lolly stick is 2mm thick, perfect. Then I found that the lolly stick has a nasty habit of falling between the boards which makes it awkward to fish out again, so the solution was to drill a tiny hole and fit a piece of wire as a cross-piece.
I’m managing to joint one board per day – that’s three joints per board. Seems slow, but there are several steps in the process: first check that the joint needs adjustment – about two-thirds of them have so far – then set up the saw guide with the lolly sticks and lots of clamps to hold the boards flat on the table, do the cut, undo the clamps and check that it’s OK, if not do it again. Then the guide has to be manhandled somewhere (I’ve cleared a high shelf) while I re-do the biscuit slots which again needs lots of clamping to make sure the board is flat on the table. Then test again and finally set up for gluing, and leave the clamps on for at least half an hour before moving it aside for the next one.
On the subject of gluing, I’ve discovered silicone brushes. Work a treat and easy to clean. I’m using Titebond III on this job.
All the 6-foot boards are done now, I’m halfway through doing the first eight-foot one. I’m glad I tested the concept on the shorter boards first.
And now I’m thinking about flattening the boards. Never had this problem with plywood… I’ve got a belt sander and a random orbital for going up the grits, but I think I’m going to try starting with a jig for the hand router to skim off the top before sanding. Watch this space.
My current project, the big display cabinet, is too big for my tiny workshop as it was, so I’ve changed it around so that I can work on the eight-foot boards in comfort – there is just enough room if the bench extends into the window recess. The work I’ve done on the boards so far was in the garage on a makeshift bench made from a piece of 18mm plywood across the table saw and roller stands. But it’s too cold to work in there at this time of year, and the glue needs to dry indoors anyway. So I’ve brought that piece of ply upstairs and supported it between the router table, which I won’t need for this project, and the workbench. Meanwhile I’ve made another bench along the longest wall for the lathe, the little bandsaw and other bits and pieces.
There’s a lot more room to work, even with the extra bench (though I did sacrifice the linisher and the floor standing bandsaw). There still won’t be room to assemble the cabinet in there, but I can at least work on the individual pieces and it’s very good for my biceps to carry the large boards downstairs to put it together. It’s going to be flat-pack anyway. It took me three days to do the rearrangement, make the long bench, put up the shelves and decide where to put everything, but it’s going to pay huge dividends in terms of the time to completion. For future large projects I might see about a neater bridge between the benches so I can get at the router table without having to manhandle an eight-foot by two-foot board and then find somewhere to put it. But time is of the essence, and this board will have a sacrificial purpose when I use the circular saw along the oak boards to joint them. I’ll set the saw a millimetre or so deeper than the workpiece, which will mean the plywood will develop some grooves.
Meanwhile, I think the workshop will stay like this for a long time. It never did feel quite right in its previous arrangement.
I wanted to stop this happening. My dear little Festool 1010 has had this problem most of its life, and it’s been back to the manufacturer for repair once; trouble is that they return it with no comment about the fault and there’s no way of knowing what they actually did to it if anything. Since I had a bad experience with another Festool product going back and showing the same fault again some months later, I decided not to pay to have this one fixed again. Instead, I tried one or two different ways to fix it myself.
The trouble is, the plunge mechanism is pushing against a very strong pair of springs which are trying to push the thing upwards, i.e. reduce the depth of cut. If you want to hold it in one place, which you absolutely do for a dovetail joint, you are provided with a knob on the side of the router which pushes a bolt against one of the pillars. It’s basically a friction stop, and I presume the idea is that you turn the knob as tightly as your muscles will allow. I am astonished that plunge routers don’t have a way to fix the depth of cut in a positive way. I tried bolting a piece of wood over the top of the router using the threaded holes provided for the guide, which as it happens I never use. Too clunky for words, and anyway didn’t hold the router firmly enough. So I took another look at the manual and another look at the router.
There’s a bolt on the router, whose only function appears to be to stop the thing from flying apart when you loosen the knob. It looks like an afterthought, and a lost opportunity. It is not mentioned in the manual. What I did in the end was to cut a piece of 10mm diameter aluminium tube that I happened to have, and put it round the bolt. I found the bolt came off easily enough but was held secure with Loctite as you’d expect. It’s well past warranty so I’m not bothered about being told off by Festool.
Now I can be sure that the router won’t start to withdraw the cutter into itself (and ruin the cutter in the process, due to its being too wide to fit through the guide bush) while I do my dovetails. The only downside is that you have to adjust the depth of cut now by moving the bit up or down in the collet: a laborious process involving a lot of patience, plenty of scrap wood for testing, a spanner and two steady hands. Mark 2 will probably involve a threaded bolt with a nut on it, which can be tightened down when the depth has been set with the knob. My friend Dave at Axminster Power Tools is going to suggest it to them next time he talks to them. I wonder that they didn’t think of it years ago. Meanwhile, you saw it here first.