On New Year’s Eve we moved into our new house in Great Wilbraham, Cambridge. This is the start of a long held dream to build furniture professionally and teach chair making classes in a permanent, planned workshop.
I’ve been building chairs for about 15 years and started teaching woodwork and particularly chair making ad hoc a little while ago. Since then I’ve wanted a permanent base that I could set up for students to take short courses in the different chairs and stools I build.
We feel incredibly lucky to have found a house with two workshops that were used by wood trades for a couple of hundred years; one as a wheelwright’s shop and the other as a general carpenter to serve the local community. The buildings themselves require a lot of work; roofers will be first in and then I can start setting them up properly.
I will be spending the whole of this year working on the property, building chairs and going to shows to promote our courses. A mountain of ash is being delivered next week so there should be a few more blogs posts. In the meantime most of my woodwork is being done with a chainsaw to get rid of the dead trees leaning against the buildings!
Teaching chair making is a fairly involved business; most courses are five days or longer. I’ve been looking for a post and rung or ladder back project that I can teach over a weekend or three days. Windsor chair makers have the simple three legged stick stool that can be knocked together in a morning. Add a bit of seat saddling and it’s a day long course. Put some stretchers on it and maybe a fourth leg and it’s a weekend.
But I want students to get the chance to do some weaving and make the piece their own. I’ve made a number of square stools that are a lot of fun to build and have basic, right angle joinery that’s ideal for an introductory course. But there’s a lot of weaving there! Plenty of opportunities to go wrong and a workout for inexperienced hands.
Probably the most useful design I’ve built but a lot of weaving for beginner.
So I drew this little stool with three goals in mind: you should be proud to take it home with you, you should enjoy a range of skills while building it and you should be able to do it in a weekend (perhaps a bank holiday weekend?). I think it’s quite pretty as a small stool but it would easily grow into a bar stool; longer legs with less angle and stretchers at different heights to accommodate different leg lengths would turn it into something really useful at a kitchen counter.
This is the first version. The next will have a narrower seat frame and a bigger seat. That will make it more comfortable but take a bit longer to weave. That won’t be a great hardship; it took less than an hour to weave this little seat. The tenons aren’t quite where I want them and the
Construction is fairly foolproof and uses a couple of simple jigs. More on those in a future post. I’m using socketed tenons for the leg to seat frame joints. Again, these deserve their own post but suffice to say I’m very happy with them.
In the summer I started a very exciting project which has been derailed, or at least shunted into the sidings, by a slipped disc. Now that I’m getting back on my feet, both figuratively and literally, I’m itching to get out to the workshop and crack on. Wiser, more patient, people have urged caution and so instead I’m editing video from the sofa. All of this was shot back in early August and it’s been very encouraging to remind myself of the progress so far. I can’t help but feel that stitching these butterfly keys into a crack is a metaphor for the exercises I now do every morning to save my own back. Or is that the diazepam talking?
It’s been a while since I built a Windsor chair. In the last few years I’ve focussed on ladder back or post and rung seats which don’t require a slab of mature tree. However an extraordinary opportunity to reproduce a very interesting eighteenth century chair has presented itself and I put on hold a number of other projects. I’ll be going into details about it in future posts but for now here’s a video of me rescuing a very precious bit of Scottish elm from a creeping shake.
I had a lot of different ideas that I wanted to try out but didn’t want to build four or five similar chairs so I’ve put them all in one. As a coherent design it might not work very well…
I haven’t steam bent much beech and I don’t think I’ve ever tried bending kiln-dried beech so this was a worthwhile test. Steam bending is trial and error and I broke a number of legs before I worked out the limits of the timber. Definitely workable but not ideal. That said I like the ray fleck in the quarter sawn slats so much that I’ll probably use beech again in future.
I’m using graduated straight slats for this chair. I rarely use straight slats and I wanted to play with the graduation and spacing. It’s just about what I was looking for. Maybe a touch too much space between them?
The stretchers are unusual. Few ladder back chairs have two stretchers at the back and most people space them further apart. I wanted to see how it looked and I’m pretty happy with it. Time will tell if putting them close together significantly weakens the legs. I’m optimistic.
My favourite detail is the carved design at the top of the posts which I’ve shamelessly stolen from Joseph La Macchia’s cocktails muddlers. I’ll definitely be using this again.
The biggest experiment was in using a prototype boring jig I’ve been working on. I’m calling it the Bodger’s Mate. It’s a delight and I’m working on mark II. More to follow later in the summer.
I’ve been preparing for social distancing since 1975. My barely-repressed nerd is now coming to the fore. If this is what happens in the first week imagine what I’ll be investigating by the peak? Comparative awl sharpening anyone? I could set up the microscope and look at the scratch marks made by each sharpening medium. In the meantime here’s a post about drill bits. Keep your puns to yourselves…
This is what we’re looking for: a clean hole bored at a slight angle. Most of the others are chipped. Now guess which bit made this hole and see if you’re right.
I probably make more ⅝” holes in cylindrical bits of wood than all other woodworking joints combined. Given that I’m in the middle of a set of grates for my boat with more than a thousand half laps that’s saying something.
Because of this I’ve put quite a bit of time and testing into drill bits. About ten years ago I bought a forstner bit with a square shank that fits my brace. Brendan Gaffney has written extensively about these and there’s no point repeating it. I was so taken with that bit that I started collecting them with an eye to one day teaching ladderback classes. In ten years I’ve managed to accrue a grand total of… 2.
So a couple of years ago I decided to start testing other bits. Covid-19 has given me the time to apply a veneer of objectivity.
We need a scoring system:
Clean, consistent holes: very important. Chipped edges and scratches left by wandering bits are disappointing. If they don’t consistently bore the same diameter hole they’re no use. I’m double weighting this by giving a score for holes at 90° and another at about 80° – roughly the angle of stretchers into back posts.
Ease of use: they have to be easy to locate on a cylindrical chair leg, cut without a herculean effort and not stall. If they bind and need to be cleared the score goes down.
Speed: I’m measuring this in revolutions, not time. More points – lower time.
Cost: I’m including postage. Some of these are hard to find. More points – lower cost.
Availability: I thought about making this a binary score or combining it with cost. But I’ll keep it simple.
I use three species of timber most of the time: ash, oak and chestnut. Ash is disappearing from our woodlands but not yet from our timber yards. Oak is a perennial favourite and chestnut, whilst a bit prone to dents, is a great timber for chairs. If you want to know how these bits perform in your favourite species send me a piece and I’ll run the test again.
I bored four holes, 3/4″ deep with each bit in a 1 3/8″ leg blank from each species. I counted the number of revolutions each took and compared the holes. Halfway through I realised that I was using a 9/16″ Jennings bit and did them all again with the 5/8″. Then I did another set at an angle.
All holes are bored with a brace. The bits with a square shank are in an old extension. Those designed for an electric drill are in a Famag extension. None of the bits slipped in the extensions when properly tightened and the Famag extension didn’t slip in the brace.
Let’s meet the contestants.
Spade bit. The cheapest bit here. Lots of people do good work with these but I’ve never seen one used like this..
Centre bit. I threw this in because I happened to have one about the right size. In fact it’s a bit bigger than 5/8”. I had very low expectations on turned parts.
Stanley Powerbore. Jenny Alexander’s favoured bit for green wood. This isn’t green wood and these are really hard to find new. They also have only one cutter so are likely to be slow.
Gedge or Cooke’s pattern auger bit. Designed for end grain but liked by Windsor chair makers because they leave a clean hole. Interesting to sharpen.
Jennings pattern auger bit. Ubiquitous. One of my most used bits. But not for chairmaking.
Forstner bits designed for a brace. Rare, no longer made. I’ve got two so I tested both.
Famag Forstner bit. Excellent in a drill press. Saw tooth edge. I’ve been using these in a brace for a while.
Fisch Wave Forstner bit. Less saw tooth to the edge. Again, excellent in a drill press. I hoped that the wave edge gives some advantage over the saw tooth.
Wood beaver power auger bit. The most aggressive bit here with four cutters.*
Spoon bit. I didn’t even test this bit. I can make it work in flat stock. I’ve practiced with it enough so that it doesn’t wander around the workpiece but I couldn’t get it started anywhere near the mark in round stock. It’s here to say: don’t bother.
There’s one obvious bit missing: the brad point. Lots of chairmakers like these in electric drills. Curtis Buchanon and Pete Galbert both recommend they be used at full speed. Given that I’m using a brace they’re not really relevant. They’re also fiendishly expensive this large so I didn’t put them in the test. That said – if you’re using an electric drill big brad point drill bits are worth getting or grinding yourself.
Many boring hours later I had some surprising results:
Bit
Clean/10
Ease/5
Speed/5
Cost/5
Available/5
Total
Spade
2
2
1
5
5
15
Centre
9
4
3
4
3
23
Powerbore
7
4
1
1
2
14
Gedge
1
2
5
1
1
10
Jennings
5
3
5
3
4
20
Forstner for brace 1
6
3
2
1
1
13
Forstner for brace 2
7
3
4
1
1
16
Famag forstner
8
4
4
3
5
24
Fisch wave
7
3
3
3
5
21
Wood Beaver*
2
2
5
3
5
17
Not what I was expecting either!
The hole nearest the camera in the first photograph was bored by a centre bit. It was consistently the best. It’s also the easiest to sharpen. However there’s one criterion I didn’t measure – consistent sizes between different bits. I’ve got a couple of centre bits that are roughly 5/8″ but that’s not really good enough. I need to be able to match them, consistently to a tenon former of a caliper on the lathe. Centre bits are all old and whilst very easy to find used aren’t consistent. If you’re working on your own and only need one bit you could do a lot worse than get one of these, keep it sharp and match your tenon former to it. It’ll work well.
But if you want half a dozen bits that are interchangeable and match tenons formed on the lathe then the Famag is the one. The Fisch was disappointing. It didn’t chip out but left a fuzzy edge along the grain. Not terrible but the Famag was better.
The biggest surprise was that the modern power bits were better in a brace than the old bits designed for the purpose. Even if cost wasn’t a factor I would be using the Famag.
It’s worth noting that the Jennings excellent at 90º but with even a small angle it produced a lot of tear out.
Most disappointing was the powerbore. I paid a lot of money both to buy it and get it here. Save your pennies.
Winners
*I previously called the Armeg Wood Beaver bit a Wood Owl. I don’t own a 5/8” Wood Owl but I do have one in 1” which I use for drilling dog holes in workbenches. The bit shown here and tested is a 16mm Wood Beaver. Great for drilling fast holes at right angles to flat stock. Not ideal here.
As with tools I’m trying to keep jigs simple and few. But this is chair making so they’re unavoidable.
Jigs and forms are used for bending, aligning and holding pieces of timber. Given that chairs are fairly complex shapes with lots of curves the jigs chair makers use get pretty specialised and this can put off the novice.
Leg bends seem to attract the most complex jigs. Have a look at Jeff Lefkowitz’s jig-as-artwork for the double curves in Boggs chairs. Wonderful. But if we’re building country ladder backs or Arts and Crafts chairs we only need one simple bend and we can get that with a block and a few clamps. Not much of a barrier to entry.
Curved on three faces this simple block acts as the bending form with the legs clamped to the bench and then later as the drying form with the legs tied across it. Here I’m lining it all up before steaming.
The back slat forms are more involved. I have used the traditional ladder style for these but I don’t really like them. If you don’t prebend the pieces they produce more of a kink than a curve and are better employed as drying forms after the slats have been mostly set in a more supportive form.
This jig will do double duty to hold the slat when carving the shape into it and so is worth spending some time on. If you want to cut down on the work you can just build the convex side and clamp the pieces to it but I have found that the sandwich method is better all round.
If you really want to cut down on jig building you can clamp the ends of the slats to the bench over the block but it won’t give you much control of the curve and ties up bench space.
Drilling holes in legs also seems to attract a lot of complexity. There are all kinds of shop-made devices for marking a centre line and drilling a hole. Mirrors, spirit level jigs and lasers all come out to solve the problem: how do you drill at a correct and consistent angle?
This is the simplest method I can find. I put a leg on the two joiner’s saddles I used for planing and scraping earlier and clamp them down. Then I mark the centreline by the extremely complicated method of using a right angle block of wood with some pencil graphite on it. This leaves me with a neat line along the length of the leg. Given that my bench top is flat I can then use this as a reference surface to judge whether I’m drilling straight. A square on the bench takes care of the angle.
Simple…
The second set of holes in each leg must be at a specific angle to the first. Loosen the clamps or holdfasts, insert a dowel or stretcher, slide up a parallel sided block with a bevel gauge on it, clamp it all back down. Mark the centreline and drill. Harder to explain than to do!
Just the bevel gauge. The chair is made in England.
It’s not really a jig but the chair stick is worth mentioning. I build mine rather robustly from the same section stock as the legs. This means that when I lay a leg next to the stick flat on the bench I can put a square across both to mark all of the joinery.
Not essential – you might not think it’s worth making for your first chair – but it’s definitely worth it if you plan to build more.
Akin to the chair stick is the bevel board. I put all of the angles needed for each chair on it. Given that the geometry of chairs is fairly well established you might never need to make more than one.
Not for this chair! This is for a bench I built last year but you get the idea – mark the angles on a piece of wood and then you can quickly reset or check your bevel gauge.
Every chair making book I own shows the author sitting on a shaving horse contentedly pulling at a stick with a drawknife. On two of them it’s the cover photo. I’ve spent many happy hours doing the same myself, but a shaving horse takes up quite a bit of space in my little workshop and I rarely use it for anything but chairs. And it is the very definition of rabbit hole workshoppery: making the tool to make the thing. You can spend hours building a museum quality shaving horse before you start building chairs.
My drawknives see a little more action at the bench but they get harder to use the drier the timber so often I find a different tool if I’m not using green, ring-porous wood.
If you’re reading this you probably already have a jack plane and a workbench of some description which means you’ve already got the tools to start building chair parts.
Not needed here
While I was building this chair I tried to use common joiners’ tools before I picked up a specialist item. A couple have found their way into the kit when I felt the outlay was small and the time saving and precision were significant. So here’s the list:
Essential tools
Jack plane
Chisels: 25mm (1″), 6mm (1/4″)
Cross cut saw
Rip Saw
Tenon Saw
Mallet
Bevel gauge
Combination square
Awl
Tape measure/folding rule
Marking knife
Brace/electric drill
Bits:
5/8″ nominal
3/4″ nominal
25mm (1″)
Bit extensions if your bits are short
Tenon rounder 5/8″
Spokeshave
Marking gauge
Craft knife
Leather scraps
Glue brush
Sandpaper
2x quick grip clamps
2x sash clamps or large F clamps
Cable staple gun
Wire cutters or heavy duty scissors
Wallpaper steamer (or other method of making steam)
Plastic bag or steam box
Optional but recommended
Hold fasts
Lump hammer
Deadblow mallet
Heavily cambered iron for jack plane
Concave scraper
Greenwood pencil
Steam-proof gloves
Most of this is self explanatory but a few things are worth a note:
Spokeshaves
Old and new
Modern, ‘premium’ spokeshaves have quite long soles. Their metal antecedents did not. My old £5 Record A151 is 19mm from toe to heel. My Veritas is a full 5mm longer. This makes the Veritas easier to use; all of the extra length is ahead of the iron so that it’s easier to register on the workpiece without rocking. It’s a clever design by the manufacturer that makes the learning curve much shorter. Unfortunately it makes all other curves much larger.
About as tight as the A151 will cut on a concave curve
The shorter sole of the old Record (and its Stanley cousins) means that it can create smaller radius curves. This is very helpful when smoothing the concave curve of the back slats on this chair. You could buy a round bottomed spokeshave but it’s another tool to sharpen and store and they are a bit trickier to use. Old (and new) wooden spokeshaves are limited by the size of their irons. Many have longer soles than the 151 and the length is behind the edge.
Bevel gauge
A long blade is essential
One is essential. A second is not a luxury. If you don’t have one already my recommendation is the 10″ Stanley No. 18. It locks with a screw from the bottom that runs through the stock and so sits flat either way around. It also locks solidly. They come in different lengths. For the purposes of chair making get the longest you can find.
Scrapers
20 minutes vs £7.50
To get the posts and stretchers close to round without a lathe a dedicated scraper is an excellent tool. You can buy ‘chair devils’ but it seems like such an extravagance that I never have. For under a tenner you can get a pair of precisely sized spindle scrapers. It’s hard to argue with the price but if you do get them make sure that you grind the corners off or a moment’s inattention will leave you with deep scars in your work. If you have a grinder and a bit of old saw plate or a spare cabinet scraper you can roll your own and get a much more convenient tool. I put a 5/8″ curve on one side and 1 3/8″ on the other flaring out to take a wider piece.
Not an HSE approved technique?
Steaming
It looks so tame until you fill it up and plug it in.
I’ve used a steam iron, an electric kettle with the switch taped down and several combinations of camping stoves and pans to generate steam but the easiest and safest solution is a wallpaper steamer. At about £40 you might think this is a luxury and I wouldn’t argue but if you don’t already have the makings of a jury-rigged death trap and are planning to buy something this is your best bet. You can still do yourself an enormous amount of damage but you can do it continuously and reliably from a handy flexible hose.
Chair parts cooked to perfection.
To multiply the risk of scalding injuries you can forego the traditional steam box and heat your back posts and slats in a plastic bag. This is a technique used by boat builders to steam planks in place and scales down well for the occasional chair maker. Once you catch the chair making bug you’ll quickly decide to build a box but a thin steam-filled sack of seething heat will cut out one obstacle to bending timber.
It might be time to replace those…
Rather than add to the terror by pressing into service that moth-eaten pair of old leather gloves for handling the scorching hot sticks it is definitely worth investing in a pair of bakers’ steam-proof gloves. Don’t use them for anything else; you don’t want to wear a hole in them. When faced with the collapsing pile of red-hot cling wrap that your steam bag turns into the moment you touch it, these will give you a bit of confidence, if not dexterity.
Clamps
They pull stuff apart too
Irwin Quick Grip clamps are that very rare thing in woodworking: excellent and cheap. They may not be the most robust clamps or exert the greatest force but they are incredibly useful. I keep three 600mm medium duty clamps on the bench during dry fit and glue up. I only use two but I’ve had the grips pull out on a couple which involves a couple of minutes with a screwdriver to reassemble them. It’s time you can’t afford when the glue is cooling so it’s worth having a spare on hand.
When Quick Grips aren’t strong enough to pull two pieces together you need the mechanical advantage of a screw clamp. I have a few 600mm F clamps that have a deeper reach than bar clamps and can pull even the most recalcitrant ladders into line. They’re particularly helpful on the back slat bending forms.
Tenon Rounder
This is the one specialist tool I would not be without. Even though I have three lathes (I know, I know) and generally turn chair parts to completion on them I still use a tenon former because I’ve matched it with my favourite bit. You could shave all of the tenons to size. Jenny Alexander did it this way and it can work well. But it takes a long time. Still – it’s pleasant work seated at the shaving horse. I prefer to use this tool and then scrape the transition. Here’s the maths: this chair has 24 5/8″ tenons. At £40 for the tool it’s less than £1.70 per tenon for one chair. Build four chairs and it’s under £40p. Your decision.
Bits
At most you need three sizes of bit to build a ladder back armchair: 5/8” for the stretchers, 3/4” for the arm tenons into the back posts and 1” for the front posts into the arms. But you can cut out the 3/4” if you’re happy to have a slightly skinny tenon into the back posts, as I did here.
Now you have a choice of bits. Traditionalists might like an auger bit in a brace but you risk the long lead screw coming through the opposite side of the workpiece. My favourite chairmaking bit is the square shanked Forstner bit in a brace but I can’t recommend it because you might wait for years for a 5/8” to come to the market and then you’ll have to sell a kidney. So the choice is really down to modern bits designed for high speed drills.
In an electric drill modern bits guzzle wood as if the worker’s livelihood depended on the industrial production of hamster bedding. But if you’re planning to adapt them for a brace you will find saw toothed Forstner bits rather less impressive than their single cutter ancestors. They’ll work but you might be there a while.
If you’re buying a dedicated bit don’t get it until you’ve tried the tenon former. I find a 5/8″ hole a bit sloppy for my 5/8″ tenons and so use a 15.5mm Forstner bit which is perfect (and more than .3mm smaller than 5/8”!). You can adjust them a hair but they’re finicky. Whichever bit you decide to buy get the long version or buy an extension. More on this later…
No lathes were harmed in the making of this chair.
I started this series of blog posts as an article for F&C magazine but by the time I was halfway through it two things had happened: it was more than double the word count for project articles and the editor had moved on! Rather than chop it down I’ve chosen to publish it here so that none of the detail is lost. I’ll be posting weekly as I write up each stage.
Chairmakers’ workshops are full of specialist tools: froes, shavehorses, drawknives and spindle lathes. They’re a lot of fun and worth learning to use if you want to build a lot of chairs. Finding straight, clear, green wood presents another hurdle (sorry) to the prospective bodger. But for the urban woodworker labouring in a cramped workshop without a ready supply of freshly cut ash and with just a few basic woodworking tools there are alternatives. Ladder back, or post and rung, chairs can be built at the joiner’s bench from material available at most decent timber yards. You don’t get to sit down as much and it may take a little longer but the results can be indistinguishable from traditionally made chairs or as different as your imagination allows.
Over the next few weeks I’m going to look at ways to build ladder back chairs using a small tool kit and as few jigs as possible. It’s not the way I learned to build chairs but it may make getting into my second favourite form of woodwork a bit easier (in answer to the obvious question: boats) .
I’m not suggesting that this is the right way, the easiest way, the quickest way or the most enjoyable way. But it is a way that you might be able to start tomorrow without a big outlay.
Timber
Finding the straight grain in chestnut
You’re going to need to bend wood if you’re building ladderback chairs and in the absence of green wood the next best thing for steaming is air-dried timber, though the chair made in this series was built entirely from kiln-dried stock. The traditional timbers, ash, oak and chestnut, all work well but more important than species are straight grain and lack of knots. Given that you’re not going to be splitting the timber your choice is wider than that of traditional chair makers. A straight, clear board of English cherry is an enticing prospect. You don’t see many cherry chairs on this side of the pond. Walnut, a diffuse porous timber not readily given to convenient splitting, also makes a striking chair.
Ladder backs are more tolerant of dry wood than some of their Windsor cousins. Gentle sweeps in the back posts rather than the tight curves of a sack back chair will make your bends easier, require less kit and be less prone to failure.
The project begins at the timber yard. Find one that will let you look through the boards available and choose the straightest, clearest piece of hardwood you can find. I have had a lot of success bending force dried timber and once managed to get a curved stem for a canoe out of a piece of kiln dried Western Red Cedar with nothing more than a towel and a steam iron, but not without a few breakages. Find a timber yard that processes its own boards from log to plank and ask to pick out a stick before it gets to the kiln.
The natural curves of the plank offer themselves to the back posts but then how do you round them?
When selecting a board don’t focus exclusively on how straight the grain is on the face but also look at the edge. If there’s more than an annular ring of runout per inch keep looking. There’s a decent board in there somewhere.
Keep it as long as you can for as long as you can. It’s tempting to cut down a long board to get it into the back of your car but if logistics allow don’t cross cut it until you’ve got it back to the ‘shop and can plan your posts, rungs and slats around the shakes and small knots in the board. It’s worth taking your chair stick with you if you’ve already made one. More on this later…
I’m using Chestnut for this chair. It looks a lot like oak but without the medullary rays or cats paws. There’s very little sap wood on a board, the grain is similar to oak and works a little easier. I prefer working it to dry ash but it’s quite a bit softer and it’s easy to put dents in. I spent some time steaming a few out. I got most of the chair out of one board 1800x400x42mm. You could do it from less; I was working around some knots. It wasn’t the most efficient way to work. Ideally I’d have bought one board at 42mm for the posts and another at 32 for the stretchers. If you can get a thick board and resaw it for the all of the slats it makes a lovely pattern. Here I settled for two and two.
I’ve been testing curves for back slats recently. That’s meant a lot of time with my compass plane making bending forms. That plane is a chatterbox. It’s in its nature. There are so many light, movable parts only partially attached to each other that it’s a wonder the thing can stay quiet at all.
Roughing in the curve with spokeshaves
Most plane makers go to great lengths to make their tools out of heavy, solid lumps of stuff. It keeps the chatter to a minimum. Compass planes are not built the same way.
The handles on my straight spokeshave show a lot more wear than on the round-bottomed tool. You can get quite a lot of curve before you need the curved sole.
Cambered iron
But there are things you can do. Starting with low expectations helps!
I used to think of my Record 020 as a jack plane. I expected it to do a lot of work quite quickly and give me a decent result. These days I see it more like a jointer plane. I use it for the last few shavings to get the final shape. The curve comes from a bandsaw, jigsaw or bowsaw followed by spokeshaves. They are my jack planes for curves.
As with all edge tools start with the sharpest iron you can hone. It won’t solve everything but at least you’ll know that’s not one of the issues. Grind and hone it like a jointer plane iron – with a small camber. Rather than trying to take a full width shaving I work the high spots and check for square frequently. I don’t expect to get beautiful long ribbons from end to end. Given that we’re making a curve the grain direction will change at some point and these things don’t go up hill!
The mouth and bed aren’t flush. Not ideal but it works.
If you’ve got a sharp, cambered iron, lightly set, you’re cutting downhill and you’re still getting chatter there are a couple of things worth investigating. The mouth of the plane is a magnet for resin. It builds up and needs to be scraped out. There’s little you can do about the step between the mouth and the frog. The frog has no fore and aft adjustment. I’ve tried shimming it with mylar and sheets of tin foil. Not worth the effort. Make sure that the cap iron fits well and the lever cap is tight.
With the mouth clean have a look at the peened pins that hold the frog to the sole. With the sole set for a concave curve these can stick out and catch. You won’t notice it when planing but it can’t help the chatter. You can sand the sole much as you might lap a smoothing plane. I didn’t notice a lot of difference but it can’t hurt.
And finally, with the plane perfectly set up a squiggle of wax on that rather rough sole makes the world of difference.
Not the most satisfying shavings but it’s the curve we’re interested in
On a chair leg’s journey from square to round (for the pedants: from cuboidal to cylindrical) there are several options for marking it out to get to octagonal. I’m a big fan of the spar gauge; they’re handy for any piece that tapers along its length. But for building the occasional chair a dedicated tool may be a bit much.
Here’s another way – one that I use a lot even though I have a couple of spar gauges in a draw.
Plane the future chair leg square to a hair shy of the final diameter.
On one the end of the workpiece mark the centre using the 45 degree fence on your combination square.
Draw a circle (or just a quarter of a circle) with a pair of compasses.
Mark a tangent using your combination square.
Set your marking gauge to the point where the tangent meets the edge.
Use this setting to mark the length of the workpiece.
Set the leg in joiner’s saddles and plane until the marks just disappear
Draw a line on all eight sides.
Plane a few strokes until your piece is an even 16 sides. No need to gauge anything here – trust your eye and the length of the ever decreasing pencil lines.
The Quiet Workshop 