Naked ladies

naked ladies 1000This is a ‘puzzle’ designed by Stephen Miller of Pyro Puzzles, and it’s quite fiddly to do, especially the face. So I actually turned the job down at first, and asked a friend to try and do it on his CNC lathe instead. The difficulty was finding hardwood in a big enough size that is not horrendously expensive, so he tried it with softwood, which suffered bad tearout. The deadline was fast approaching, so I persuaded the client to let me do it in a smaller size and took it on with a week to go, with some 2×2 sapele that I can get easily. The whole sculpture is about eight inches high.

The idea is that you present it in bits and the recipient puts it together, wondering what on earth it is.

Because it’s done by hand, the spindles aren’t identical even though they’re done from the same template. So you have two backs and two fronts that are slightly different. That means you’ve got four potential ladies, but only three in any particular configuration of spindles.

Finished in cellulose sanding sealer and microcrystalline wax.

Bines

img_20161107_203214017I thought I’d have a go at one of these. This is quite a big one; the bigger ones are easier to start with. When the bines (apparently that’s what they’re called, maybe from ‘bent tines’) are far enough apart to get your fingertip in between them it makes sanding easier.

I started with a Web search and found this by Richard Madden. It’s an excellent explanation of how to go about it.

I started with an old piece of walnut – a close-grained wood but a frankly grotty example. I thought if my first attempt went wrong I wouldn’t have lost much. But actually I’m quite pleased with it.

img_20161106_161021483I started, as instructed, by turning the basic shape, a sort of teardrop outline. The tailstock stays in place for the whole job, except for the final sanding of the top, but the base end also starts life in the chuck. The tailstock is there for support and to keep the centre in place but shouldn’t have any pressure on it, otherwise the bines could snap unexpectedly during the roughing out.

Once you have the basic outline, you put on the pencil marks. I started with the lines round the piece: with the lathe running slowly and the pencil on the toolrest I marked the top and bottom of the cutouts, and three more lines roughly equally spaced between them. Then, with the help of the index wheel on the headstock, I made eight equally spaced marks around the piece. I used the toolrest to provide a line of sight along the shape so I could mark the eight points round each circle. Then it’s a case of putting in the diagonal lines by hand and eye.

The next step is to get out the drill with a brad point bit. I used a 6mm bit. This step saves a lot of carving. Richard had only four lines and drilled along them; I’ve drilled between lines, either is fine. Drill towards the centre axis.

After the holes you get out the Dremel (I use a flexible shaft and hang the motor on a hook nearby). The bit is, well I’ve lost the packaging and I’ve forgotten what it’s called but it’s there in the photo. It’s very rough and ideal for this job. Start with a groove along the line of the holes, then come back and push deeper. The groove helps the bit to stay in place and not skid over the outside surface.

I’m not practised at this, in fact this was my first time with that particular carving bit. Yes, it is skittish and makes deep scars, so you need to make sure they are where you want them. I use a platform on the toolpost to rest my hand on, and I found it was worth locking the spindle. And another point that Richard made is – unplug the lathe! The brain naturally goes to the lathe switch, and turning on the lathe when you’re meaning to turn off the Dremel is not a good idea! I also had the extractor on to pull the dust away.

Eventually you develop a hollow in the middle, greatly helped by the holes from the drill, and the bines are taking shape. My best suggestion, having done it only once, is to do as much as you dare with the power tool before you get out the sandpaper. Sanding is the big marathon.

img_20161107_120325668Don’t get me wrong, I enjoy sanding on the whole, but I do find myself thinking about a cup of tea more often at this stage. Best to use Abranet (which has a hook-and-loop backing) or a cloth-backed sandpaper and cut it into thin strips, about 12mm wide for this project, probably even narrower for a smaller version. Insinuate it round a bine and pull from side to side to tidy up the back of each bine. I started with P80, then through the grits to 240.

Take another look at it and see if it needs any more power carving and take a look at the other Dremel bits you have. By this time you’ve had a bit of practice. Find something finer and use finesse to insinuate it where you need it. I expect I’ll have more to say in future when I know the terminology and can show you what works. As it is, I decided with this piece that since its only function is to be ‘my first attempt at a twisted finial’ I would stop before I ruined it with a tool I’ve never used before.

I finished it with Osmo worktop oil, since I’d bought some for my kitchen worktop and had a lot left over. It’s excellent stuff, and foodsafe too, so it’s good for things like salad bowls and goblets.

Locked mitre joints

abacusThis is another autistic training aid; the idea is to illustrate that autistics often leap to one extreme or the other rather than settling somewhere in between. Personally, I think it could also illustrate the way some of us get into a swither because we can see both sides of a debate and the more we think about them the more equal their appeal becomes.

The bead is yew, which has one side darker than the other, and the frame is made from four different woods, clockwise from top: tulip, oak, sapele and laburnum. The rod is pine, which to my surprise was the stiffest 6mm dowel I could find at the time. I decided to do it with multiple woods, to illustrate (well, like the constellation sculpture you can read whatever you like into it but anyway) that wherever we look we see something different.

My first attempt had the frame all in one wood, in fact it was the tulip, and it wasn’t just boring, the proportions didn’t seem right and I did it with straight mitre joints. In the process I rediscovered how much I hate mitre joints. Then I found a locked mitre bit going at half price at Rutlands, just the job – once I’d figured out how to line it up properly on the router table! locking mitre bit sled1Two YouTube videos came to my rescue, one showing how to line up the bit to the fence and the other showing how to make a simple, disposable sled for the workpiece which would keep the wood at a perfect right angle to the cutter both on the vertical cut and the horizontal cut.

The sled is just a piece of plywood that is thick enough to stay straight, with two pieces of wood, the same thickness as the workpiece, screwed on so the workpiece fits snugly between them. The same sled works on both the vertical and horizontal cuts; I just used both ends of it. sled lineupIt holds the workpiece steady, keeps my fingers away from the cutter and is made from offcuts – what could be simpler? It also avoids tearout because the cutter has to cut the sled to the right shape in the process. So I found that the sled got shorter as I went, because it has to be cut down for each try cut until it lines up properly.

sled2

For both cuts I attached a piece of board to the fence with clamps. It just had a small cutout to clear the cutter.

After several try cuts (always cut more wood than you need) I finally had the fence and the cutter height adjusted perfectly.

For rounding the pieces before assembly I used a quarter-ellipse cutter, and used spare offcuts to hold the pieces in line with the fence.

The piece is finished with sanding sealer and wax.

Taiji rulers

taiji rulers 2These strange-looking things are called taiji (tai chi) rulers, not because they measure anything obviously, but probably because they keep your hands at the same spacing when you’re using them for qigong exercises.

They fit comfortably in the hands and can be held in different ways, depending on the exercise. They are excellent for gentle exercise for elderly people as well as for martial arts work, and they are very tactile.

It looks as though I shall be making quite a few of these. I’ve already sold two of the first three I made.

More of a writeup here.

Egg cups with captive rings

egg cups

These egg cups were made for a client who likes captive rings. From left to right they are: apple, ash, laburnum, hornbeam and yew. Finished with friction polish and wax. Just in time for Easter! After the third one I was starting to get the hang of it, but the most nerve-wracking bit is detaching the ring.

The captive ring tools you buy tend to be shaped for a particular thickness of ring; I tend to prefer larger rings that don’t look like they’ve been milled. The tools I use I actually got second hand and are home made from bent masonry nails, one ground for the left side, the other for the right.

IMG_20160317_154140370I started with the inside of the egg cup, because that’s the shape that matters, and because that way there’s more wood to support it and keep it stable. I used a ‘reference egg’ made from a thin piece of wood and sized for a large egg, 47mm diameter, as specified. The flat shape allows me to check that it fits the cup without having to move the tool rest. The egg has to sit nicely without bottoming out. If the bowl got too wide, I simply took the top couple of millimetres off the rim and went deeper. At this stage I haven’t yet committed myself to where the base goes. I at least wanted all the egg cups to be the same height. Once I’m happy with the inside shape, I can then mark where the base is.

The next stage is to shape the outside of the bowl to a reasonably uniform thickness. The client wanted a thick stem, and the stem thickness is largely dependent on what it looks like when the ring comes away. It does look distinctly untidy, at that stage. I like to hold the ring out of the way with masking tape when I’m tidying the stem; many turners don’t bother on the grounds that the ring gets out of the way of its own accord but I still find it a distraction, especially with such a short stem.

You have to shape the ring and sand it before detaching it, but I did pick up a trick to sand the inside of the ring after it’s been detached. You just wrap sandpaper round the stem, hold it in place with tape, run the lathe slowly and hold the ring against the rotating sandpaper.

sanding captive ring

When it’s all sanded down to 400 grit, it can be sealed before parting off at the base. Reversing the cup to finish the base is always a challenge, and I’ve used my home-made wooden chuck jaws, which I don’t have a photo of to hand but will show in another post.

I then buffed the egg cups on a buffing wheel with buffing compound, followed by Chestnut WoodWax 22, which is toy safe and reasonably water resistant.

Spindle thread revisited

My wonderful husband looked on the Web and found that the spindle that fits my chucks is available for my new lathe after all. Thanks to Biven Machinery, I now have it, and with a judicious combination of brawn and brains it is now fitted. Thank goodness for standardised parts. That spindle fits other lathes in the series. Now all my chucks are usable again, and the one I bought for the new thread has a much neater adapter because it’s small to bigger rather than the other way round. So I now have four chucks, that I can have different styles of jaws fitted to.

I recommend their level of service; they really do go the extra mile.

Two more projects in the portfolio; click on the image for the writeup.

coffee scoop        segmented vessels

Constellation

constellationThis project is a sculpture based on a concept by Caroline Hearst, an autistic-awareness trainer who wanted a visual representation of the autistic spectrum to bring to her training sessions. The idea is that autism is more of a constellation than a spectrum, in the sense that it has more than one dimension.

This sculpture can represent a whole range of dimensions. There’s the obvious 3-D arrangement of the 19 balls on the ends of their springs; Caroline wanted a cluster in the centre to indicate ‘normal’ people and a few ‘outliers’ representing people who are different. Then there is the range of woods used to turn the balls; this example has walnut, osage orange, holly, spalted beech, robinia and what I think is African blackwood. These were what I had in the shop at the time. The balls are different sizes, which can indicate anything you like as well. And there is also the variation in the springs themselves. This example has two different grades of spring; although they happen to be the same diameter, one is lighter than the other so the ball wobbles further and more slowly.

The base is made from 15mm birch ply, stained with a black spirit stain, sealed with cellulose sanding sealer and finished with wax. The project is designed so that the user can arrange the springs on the base and match them with different balls according to taste. To accomplish this, I drilled the holes in the balls and in the base to the same diameter and made a plug on both ends of each spring to fit the holes. The plugs were made from polymer clay. I originally thought to use a plug cutter and make them from wood, but they were too flimsy. The Fimo works a treat.

confimo2I discovered that the lid of a Really Useful Box, the one I happen to use to keep my seeds in, has just the right sized recess. This meant that I could make all the plugs the right size by rolling the spring under the lid on a flat granite surface.  Then it’s a case of carefully trimming the clay, rolling again and when satisfied, putting the plugged spring aside for baking. The clay cleans off very easily with white spirit at the end of the session.

The sculpture has a lid for transport, made from cedar and birch plywood. I spent many holes in the night puzzling how to do this. There are two problems, first, how to get the curved shape to fit round the base and secondly, how to attach the box to the base.

bandsawcutI chose cedar because it’s light in weight and my local timber yard sells it. The height of the sculpture fits my bandsaw so I had a way forward. After cutting and gluing the cedar pieces to accommodate the desired shape I traced round the sculpture base and made another line roughly 1cm outside it.

Here’s a tip I learned the hard way. Do both the inside and outside cuts with the lid upside down. Obvious really but I didn’t see it until I realised that however carefully I set up the bandsaw the shape at the top won’t be exactly the same as the shape at the bottom, and it’s the bottom you’re working from.

cradle2The other lesson I learned (yet again) is never to throw away any offcuts until the project is completely finished. To sand the top and bottom of the shaped lid, I set up a homemade cradle on the lathe and pushed the shape against my homemade disc sander, a disc with a chuck ring attached at the back and a hook-and-loop disc glued to it. Again I was lucky, my lathe had just enough capacity to fit the whole shape within the circle. But that was when I realised I needed the offcuts, to hold the shape straight on the cradle. Luckily I had one left, the others had gone on the fire. Of course what I could have done was to sand the top and bottom before doing the bandsaw cuts; I’ll do that next time.

conboxlidThe top of the lid is a piece of 6mm birch ply. I thought about a handle and decided to just drill two finger holes, making sure they didn’t coincide with a spring hole, just in case you had a tall spring just in the wrong place. So that was what determined the position of the finger holes. I cut them with a Forstner bit, then rounded them on the table router before gluing it to the cedar. Being glued to endgrain I decided on belt and braces and put four dowels in to make sure it wouldn’t come away. Probably unnecessary, but they scarcely show. After gluing, the lid is flush trimmed on the table router and then rounded.

slotsOf course it was after that that I needed to finalise the attachment of the base to the lid, so here was another mistake. I decided on comma-shaped pegs in three places, which when open allow the lid to surround the base and when closed allow the lid to be used to lift the whole thing. Easy to operate, and no bits to lose or fiddly hinges and catches. So I’d already made three slots in the sculpture base and corresponding slots in the bottom of the lid. But then I realised there was a weakness: the wood under the slots is very fragile because of the orientation of the grain. True, the screws holding the pegs would carry the load, but in any case the endgrain isn’t terribly pretty. The matter was decided when I did in fact break the cedar when try-fitting a peg, so it was back to the drawing board. Another piece of 6mm ply came to my rescue and formed the rim at the bottom of the lid, flush trimmed and rounded like the top. I re-did the slots to the same height as those on the base but I had to do the slots from the inside relatively blind because the lid top was already glued on. So next time the rim goes on first.

conboxpegsThe pegs were adjusted by trial and error; they are each on a differently curved part of the lid so each one has to be individually shaped and its pivot point determined. The pegs are 4mm ply.

conbox1

 

It remained only to sand and finish; the base and lid are finished with cellulose sanding sealer and microcrystalline wax, the pegs are finished with wipe-on poly and wax.

 

 

Beware the spindle thread

So anyway, I have finally succumbed to the yearning for a variable speed lathe and have gone ahead and bought one. I’d used the Jet 1015VS at a hands-on session at the local club, and it’s a joy. Instead of having to stop the lathe, open two little doors, release the tensioner and physically move a belt from one set of pulleys to another, you just turn a knob while the lathe is running. I hadn’t realised before how often I actually want to adjust the speed. Typically the workpiece is unbalanced when it first goes on, so you start at a low speed but once it’s round you want it faster.

But there was a downside. These things often don’t run perfectly smoothly (unlike the lathe itself, which is quiet and polite as long as I don’t turn it on when the index pin is engaged). Something that didn’t occur to me to check was the spindle thread. On the one at the club, the thread is the same as my old lathe so it fits my chucks. Yes, you guessed it, the thread on the new one is different. Why, I don’t know. OK, it’s metric, perhaps that’s why. The thing is, on the display model (and the way it comes out of the box) you can’t see the thread because it’s covered by a faceplate. Perhaps they do that deliberately, I don’t know. But (and tell me if this is unreasonable) it would have been helpful if the sales staff had pointed it out. I know it was in the specs, and I should have looked, but even so.

So I find myself with a lovely new lathe that won’t fit my chucks. What to do?

Well, for the moment I’m using an adaptor, which cost me another 28 quid (and two days, because they initially sent me the wrong one and I had to go to the store to sort it out) and reduces the capacity of the lathe by about two inches, if you want the tailstock up with the chuck. Well, on the old lathe, the 1014, I’d always fitted the chuck to muscle-tight, so I did this on the adapter too. It flashed across my mind while the thing was turning nicely that it might be worth standing out of the way when I stop it, and i was right. The chuck went on turning and took itself, and the workpiece, right off the lathe and on to the floor. One more piece of firewood but otherwise no harm done, thank goodness.

It’s always the first few days with a new thing that are the most dangerous.

De-skilling

I want to put in my tuppenceworth on the oft-heard curmudgeonly comment that woodturning isn’t skilled any more, that the new tools and gadgets make it all so easy that any tinpot hobbyist can soon put out half-decent stuff.

First of all, I can only think of one reason why this can be seen as a Bad Thing, and that is, power tools will all be so much scrap metal if a time should come when there is no longer any power. At that point the pre-industrial techniques will have to come out again, along with their associated learning curve. But at that point, the lack of people with ten thousand hours at the pole lathe turning perfectly straight rolling pins will be the least of our worries.

In the meantime, any hobbyist can buy the kit and pick up enough skill in a short time to turn out dishes and bowls, goblets and platters and other items of varying levels of beauty. And why not? If you can quickly learn how to make a serviceable item in the shape you want it, you immediately have scope for innovation and creativity that you didn’t have before. You can play with ideas for decorating your pieces, you can look at the forms and shapes all around you in a new way, you can experiment with incorporating different materials, you can do all these things right away.

And when you go to the local woodturning club you soon recognise the ten thousand hours when you see it. The kit doesn’t make a master out of you. You still need to put in the time and the practice, and none of that time is wasted. The worst outcome is an expensive piece of firewood (bar any lapse in safety precautions, of course; we all have our near misses and the associated scars). In the meantime, you’ve had a chance to enjoy your lathe. It’s democratic, and the standard of work is inexorably rising.

And then there’s the other techniques you start to take an interest in: pewter, for instance, which is probably the first contact with molten metal that most of us encounter. Incorporating fibreglass resin or epoxy in your work. Learning about different kinds of adhesives. The ideas for turning your mistakes into features. The joy of seeing what a piece of relatively unpromising firewood can look like when shaped. And of course the brainwork of solving problems of practical geometry.

And what’s really lovely about woodturners is that they are always willing to share their skills and clever ideas with the rest of us. What’s not to like?

Perhaps your curmudgeon is simply envious.

Quarter-sawn

quartersawnThis was the first time I’d attended the AWGB biennial seminar, held at Loughborough University, and probably also the last. Not because it’s not any good, it was very informative and I came away from it with new techniques and ideas aplenty. Not because I’m female in a group of primarily male woodturners – there were other women there. Not even because of the pompous parading of credentials and one interminably boring after-dinner speech.

No, the reason I won’t go again is that I can’t keep my mouth shut.quartersawngoblet

So when one of the demonstrators, showing us how to bend the thin stem of a goblet, tells us that this 5mm diameter piece of wood has to be “quarter-sawn, you do all know what that means don’t you?” I can’t help saying, “well, I thought I did, but…”

For an excruciating twenty minutes I was treated to ‘the lecture’ about what quarter-sawn means. It refers to the orientation of a board, where it came from in the tree. He drew ‘the diagram’ on the whiteboard. He showed how the rings are different on a radially sawn board and a tangentially sawn board. The rest of the audience joined in, trying to explain this concept to me. What they were not explaining was how a ROUND, THIN piece of wood can be ‘quarter-sawn’. A few people sitting near me did twig (to coin a phrase) that they were all answering the wrong question and tried to help me explain that. We were drowned out in the rush to explain ‘quarter-sawn’ in the clearest possible way so that this poor woman might get it in the end.

My humiliation was complete when, after it was all over, a man comes up to me and says, “Do you understand it now?” and proceeds to turn my favourite 0.1mm fibre tip pen into a 0.3mm fibre tip pen by drawing the diagram AGAIN! He then led me to one of the stands to show me the rings in pieces of wood.

I believe the expression is WTF???

So from now on, incidents like this are referred to in our family as ‘quarter-sawn moments’.

 

Puzzle Cabinet

Puzzle CabinetI’m delighted to say that the cabinet is finally finished and delivered. It was a long haul, and I’ve learned a great deal from it. It’s huge – eight feet wide – this is the first time I’ve been able to get far enough away from it to get the whole thing into the picture.
But at least if I do anything like it again it will happen a lot more quickly now that I’ve learned more about how large oak boards behave.

Finished with an American ‘wipe-on poly’, which is water-resistant and durable, and most of all, easy to apply and dries very quickly.

The client is fitting the lighting strips and the glass doors; when I see it loaded and complete I’ll add a photo of the result – watch this space.

Cabinet ongoing

cabinet try assemblyOne step forward, two steps back. Just cutting a rebate in one of the sides to locate the shelf, and realised that the side had bowed across the grain by at least two millimetres – bummer! and I had already cut it to width! Will this oak never stop moving?

OK, so what you do is, you get the track saw out again, set it up carefully (takes ages) and cut along one of the joints (the cut itself takes a few seconds), then when it relaxes do the lolly stick trick (see earlier post), clamp to stop it moving sideways but not in such a way that you put the wood under stress, and cut again. Theoretically you should have a nicely fitting joint, but for some reason that I haven’t yet been able to fathom it took three attempts. And in fact I did two of the three joints, because having cut the centre one, one of the two halves was also bowed so I split that one too. It looked as though one of the boards would need to be replaced, but thankfully it seems OK now. There will be a little more flattening to do but it shouldn’t take off more than a mm or so, still within allowable limits.

So anyway, this meant that I had to re-do the front fillets (lips? I don’t know the terminology, but I mean the L-shaped piece on the front of each side that hides the edges of the glass doors when they’re closed and generally makes the cabinet look chunkier), because I’d lost 5mm with all that re-jointing. I mean they call the blade ‘thin kerf’ but it’s 2.2mm which is plenty. So I went back to the timber store, more time taken out, and got some more wood. Luckily the weather is reasonably mild so it isn’t too hypothermic in the garage, so I got on with cutting the fillets on the table saw leaving some leeway for jointing.

By the way I’ve discovered that this oak really doesn’t like the router. Even with a brand new cutter it was tearing pieces out, even going a tiny bit at a time. The table saw seems to do a better job, and leaves me with offcuts which if nothing else can go in the fire. The compost bin already gets plenty of sawdust.

More on flattening

Well, you remember I said in a recent post that it’s essential to hold the board down while you level it? Actually I’ve had second thoughts about that. Basically it depends on how important it is that the board should hold its shape in the construction. If it’s fixed on all four corners and preferably in the middle as well, then you’ve saved wood by clamping it down. If it needs to be flat, i.e. not twisted at all, because it’s holding something else in place, then it’s better to let the board relax (perhaps hold it down in one corner or put a spacer under at least one corner so it doesn’t rock), flatten one side under the gantry then turn it over (at which point the side you’ve just done should sit flat on the table) and do the other side. Worth doing the ‘wrong’ side, if there is one, first. You’ll end up with a board that stays flat, as long as it’s not too thin by the time you’ve finished. That depends to a large extent on how well you glued them together in the first place, and of course whether you decided to risk putting a wonky board in between two others to persuade it to behave. Definitely worth dry-assembling edge-glued boards with biscuit joints for several weeks indoors before jointing and gluing. Also a good idea if you have multiple boards of the same length to have a symmetrical pattern of biscuit slots so you can interchange boards later if necessary.

Two more tips:

Make sure your cutter is sharp, otherwise you’ll be sanding out tiny gouges in the wood afterwards. I used a dish cutter because it has a flat bottom but curved sides, so any gaps or inaccuracies from the gantry are at least quite smooth and will sand out more easily.

card spacer on routerSecondly, do the flattening in multiple passes, not all at once. This makes the pass easier on your muscles, the router and the router cutter, and reduces the risk of the router tipping, which makes a deeper cut at that one point. It also means that you won’t take too much off and find the board is too thin when you’re done. I found that increments of the thickness of a business card is about right. It takes twenty minutes to do one pass on an eight-foot by 19″ board; it’s worth the extra time to do several passes.

After the penultimate sanding, I also sprayed the board with water and wiped it down , then let it dry. That raises the grain, so the board feels rough. Another quick whizz with the ROS at 24o grit makes it silky smooth again.

Flattening a large board

router flattening jigHaving 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.

router flatteningAt 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. smooth with ROSNo 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.