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Ffrom the Middle Ages until the dawn of the 20th century, wooden planes were the form of the dominant bench plane in the western world. But when I started woodworking (in the dark age of hand tools of the late 20th century), this traditional form seemed practically extinct. When I became interested in the production of floor plans, I found a lot of information about Krenov style laminated planes, but very little about traditional mortise planes.
Eventually, as I started wrapping my brain around these plans, I realized how extremely sophisticated and ingenious their design was. Virtually every function has a functional purpose, although it may not be immediately apparent. I have come to think that traditional planes, particularly British and American designs from the late 18th and early 19th centuries, represent the peak of planemaker art.
Building a traditional aircraft is a challenge, but it’s a great way to hone your skills with hand tools. It requires a small toolkit and although some specialized tools are needed, they are modest in cost (and you can get most of them if you are so inclined).
I will guide you through the design and construction of a traditional plan to smooth double iron coffins (the so-called because they look like coffins, not because they have been used in the mortuary industry!). A smoother, well-built coffin is an extremely useful and versatile tool: mine is rarely beyond the reach of the arm on the bench.
First, buy a suitable double iron. Look for what is 13/4“O 2” wide and at least 7 “long. The cutting iron should be at least 11/2“Usable length under the slot. It should also be tapered in thickness; most of the old irons are around 3/16“Often at the bottom and 3/32“at the top. Try to avoid irons that are seriously pitted or twisted. I found old irons in antique shops, exchange meetings and flea markets, including a” donor plane “with a ruined body but a usable iron. A other great source is eBay (in particular the UK site); look for “double tapered iron” or “vintage double iron”. And there is a new source for the irons: Reproductions of red roses, even if you will have to create or purchase an iron.
Next, you will need a billet for the plane. It should be at least 3/4“Wider and 5/8“Higher than iron and will end at 7 1/2“Long. If you can get it, use beech, traditional wood for planes. If you can’t find beech, there are many alternatives: hard or soft maple, yellow birch, apple and pear are all beautiful. Avoid hardwoods softer, like mahogany, and very hard exotic ones.Porous woods such as oak or ash are subject to chipping; however, a nice plane can be made with care from these woods; there are many historical examples in these species.
More important is how the ring rings are oriented. They should be as close as possible to parallelize the sole, then perpendicular to the sides. Avoid sawn billets – they expand and contract unevenly, so you’ll have a hard time keeping the iron and wedge well fitted.
Finally, you will need a wedge-shaped empty space that is approximately 3/4“Thick, long 6” e 1/8“Wider than your iron. The grain orientation of the wedge stocks is the subject of some controversy. It is clear that the 18th and 19th century planemakers preferred the strain that was squared in its widest dimension, with ring rings running perpendicular to the mouth of the plane. I wedge my heels like this; I think the old producers preferred this orientation because it reduced the likelihood of the wedge deforming, and the quarter-tail faces more easily adapt to the iron and stumps, adapting better. A number of eminent modern planemakers, however, do the opposite, orienting the annular rings parallel to the mouth.
You will need some specialized tools, but you won’t have to spend a lot of money. First, let’s talk about floats. The two floats that I couldn’t live without are one 1/8“Floating edge and a 5/16“Slip float, both cut on the push stroke. If you have a limited budget, you can make both with O1 steel (if you can deposit a saw, you can make a float). If you are building only a few planes, you don’t even need to harden steel If you prefer to buy them, they are available from Lie-Nielsen Toolworks.
If the budget allows, a bed float and a side float (always in a push configuration) are nice to have. Doing one of these by hand is an exercise in frustration, so buy them or do without. An excellent alternative is the “beveled chisel scraper” popularized by the famous planemaker Bill Carter. This is simply an ordinary sharp chisel with a 90 ° microbevel. To refine the edge, hold the chisel vertically on a rough stone with the bevel facing you and pull the chisel towards you, repeating until you feel a burr. Turn your back, then repeat on your beautiful stone. Turn again and you’re done. Do not move. Scraper chisels are incredibly useful; I have half a dozen in various sizes.
A cutting saw is also useful for cutting stumps. Some people use the Japanese-style wire saw. I prefer to create my own; the first one I made was a $ 5 drywall saw, with the whole set pressed and teeth filled for a torn cut. Since then I have made more cute ones 1/16“-Hick saw the steel. If you don’t have a saw, you can get away with the float.
Another tool you will need is a planemaker’s “caliber of descent”. This is simply a piece of flat scrap, approx 1/2“Often, cut in a U shape. Chamfer the tips of the two forks so that the gauge can fit all the way to the mouth of the plane. To use the meter, place one of the forks on the bed (or chest) and compare the other fork with the lines of the layout.
There are some other simple masks to make, but these are optional and I will cover them as I proceed.
Clean the iron
Before you start building your plane, clean the iron. A roll of 3 ″ – or 4 ″ coarse-grained backed sandpaper, glued to a flat surface, will do so briefly. As with any iron, you will have to flatten your back. Flatten the bottom 3 1/2“Or so of the front, so the plane will go well in bed. Before doing so, check that the iron is not twisted. You can easily remove any twists by grabbing the bottom 2” in a vise, putting a C-clamp on the upper third of the iron and turning it in the opposite direction. But don’t twist too much. On laminated irons, only the bottom 2 ″ is hardened; the rest is in mild steel or wrought iron, so it is quite malleable.
Billet preparation and mortice layout
Make your billet flat, square and parallel. Traditional bench tops are typically square in cross section and approximately 5/8“Wider and taller than the width of the iron, but for a smoother coffin, you need a slightly wider billet. Start with one that is a bit long and cut the ends later.
Study the grain to determine the correct orientation for your plane and label the sides and ends. Traditionally, the side of the bark is the sole and the side of the heart is the upper part. The grain on the sides, if not parallel to the sole, should flow downhill from the toe to the heel.
To lay out the mortise, start by marking the cut lines for the ends. On the sole, use a square and a knife to write a line for the back of the mouth 2 5/8“From the tip. Set a chamfer meter on the desired bed angle (I usually use 47.5 °, but anything from 45 ° -50 ° is fine) and with a pencil, mark the bed line on both sides (for all corners below, be sure to mark the corner on both sides before restoring the bevel.) After marking the bed lines, connect them across the top of the plane with a square.
Next, place the assembled double iron against the bed line and trace the front of the iron and the tip of the cutting iron. Now you know exactly where the cutting iron will protrude from the sole, so mark the front of the mouth through the sole. Try to adapt to zero play and err on the side of a too narrow mouth; you can always open it later.
Now mark the wear corner. On a double iron surface, the wear must be much more marked than on a single iron, otherwise the shavings will be trapped by the iron. The first double-crowned irons were steeper than factory-made aircraft from the 19th century. By making wear steeper, the first planemakers were able to have relatively narrow mouths, while subsequent planes had less deep wear but very wide mouths, probably because it was easier to mechanize production in this way. With a 47.5 ° bed, I use 85 ° wear (compared to the back of the hob – the angle is 95 ° to the front, as shown in the diagram).
Set your bevel and draw the wear line, making sure that the wear angles return to the bed, not vice versa! Mark a point on the wear line that is 11/8“Above the sole. This point is the top of the wear and intersects with the breast. Set your bevel at 65 ° (tilted away from the bed) and write the breast line from the top of the wear to the top of the Plane: Use a square and connect the two breast lines across the top of the plane.
Now mark the stumps. Set the chamfer meter to 9 ° greater than the bed angle (56.5 ° for a bed of 47.5 °) and position the meter 3/32“In front of the highest point of the iron, just above where the iron bends to meet the cutting iron. Draw the line from top to bottom until it intersects the wear. Do it on both sides , then connect the stump lines at the top.
Now mark the width of the rough mortise. This should be 1/2“Tighter than iron, so for a 2” iron, you want a 11/2“Mortise. Draw lines on both the sole and top of the plane and make sure the mortise is centered.
Finally, mark the width of the mortise between the bed and the stumps. I like that this mortise is roughly 1/16“Wider than the iron at the top of the plane and 1/32“Wider than the iron on the sole. I would prefer the mortise to be a little too wide than too narrow – you don’t want the iron to bind into the mortise or be difficult to adjust the square. Measure the width of the iron at both the bottom and the bottom central, where it emerges from the upper part of the plane; vintage irons are often slightly tapered in width and thickness.
Rough mortising: drill and cut
Before you start cutting, use a square and a knife to mark the lines 1/8“In front of the bed line and 1/8“Behind the breast line; these define where to roughly chop. Then use a chisel or marking marker and mark the lines that define the sides of the rough mortise. This will prevent you from tearing large pieces off your layout lines.
Use any sturdy chisel that is about half the width of the rough mortise. Start from the breast, approx 1/4“Behind the line. Create a small V then work backwards, smooth, until you are 1/4“From the bed. Hold the chisel at an angle of about 80 °, as shown below. If you find that the going gets too tough, turn the plane upside down and work in the opposite direction. Cut one side of the mortise from the bed to the breast, so do the same on the other side. Don’t worry too much about corners at this stage; just make sure you don’t go too deep and stay within the lines.
At this point, your mortise will almost certainly be too superficial, so start looking into it. You can cut or cut, but keep working with the chisel bevel down; this will give you more control and you will be less likely to cut too deep. As you proceed, tear off the side walls and check your progress often with the sink indicator.
In the roughing phase, the corners of the bed and breast meet in a V at the bottom of the mortise. Next, you will include the wear angle.
When the mortise reaches a depth of approx 3/4“Above the sole, turn the plane upside down and get ready to pierce your mouth. Scribe a line that divides the distance between the front and back of your mouth and put your holes on close centers. Make sure you stay inside the rough mortise ( remember, rough mortality is 1/2“Narrower than the iron width).
A drill press is ideal for this activity, but you don’t need it. Hold the billet in a bench vise so that the wear line is vertical and drill with a 1/8“Punta Brad. You may want to place a square on the bench as a reference. If you lose the corner, you lose by leaning towards the bed, where you have a lot of space.
While your plane is upside down, cut a mortise around 1/32“Deep, right inside the mouth layout lines. This will help prevent bursting later. Use your floating edge to saw through the mouth. If the float doesn’t pass, chisel some of the waste.
With your mouth open, it’s time to clean the bed and breast surfaces. Analyze with a chisel, being careful when approaching the opening of the mouth so as not to knock the chisel on the wear surface too strong (this can cause a bad cut of the front of the mouth). When you get as close to the chisel as possible, end up with a bed float or beveled chisel scraper. To work aggressively with a float, lift the handle and use the front tooth as a scraper. It also helps to slightly tilt the tool.
Regardless of the tools you use, keep working until the bed and breasts become beautiful and flat surfaces. If you are sure, you can work directly with your layout lines. If not, stand back 1/16“- later, I will show a clever trick with the float on the edge that will make nailing the corner of the bed easier.
After the bed and breast have been cleaned, finish the deadly mortise by removing the wear surface. Hold the billet in a vice so that the wear surface is vertical and focus on maintaining the chisel lead. Finally, cut down along the line that defines the back of the mouth. The precision here will make bed adjustment easier.
I saw the stumps
Now make three pairs of cuts with the saw or float. First, use the bed as a reference surface and cut only close to the layout lines, leaving some cleaning afterwards.
The next pair of cuts defines the stumps. The easiest way is to create a 9 ° wedge to guide the saw. It should be approx 5/16“Often at the bottom, 7/8“Often at the top and just wide enough to adapt to the mortal mortise. To leave both hands free while cutting, press the wedge into the mortise or apply some spray adhesive on the back to temporarily glue it on the bed. Next, a couple blows with a hammer will release it and the spray adhesive will clean easily with alcohol.
The cuts of the stump are somewhat more difficult because they are stopped; you are cutting to wear. Go slowly, use some wax on the saw blade and clean the crevice and often the teeth.
For the last couple of cuts, on the chest, keep the saw tilted so that the teeth touch the mortise wall at the top of the wear surface.
Then, use a chisel to eliminate the waste between the bed and the stumps. Pay attention to the direction of the grain here; on the one hand (usually the right side) the waste will come out easily, while on the other the chisel will want to dive under the surface of the cut. Make light cuts until you’ve determined which side you’re facing.
After removing most of the waste, place the floating edge against the bed on one side and you will see the lines of the layout. Then place the float against the stump on the same side and see the lines again. Remove the residual waste island with one side float if you have one; otherwise, carefully chisel the waste or use overlapping sections with the edge float. This method makes it easier to get a flat surface than to go directly to the side float.
The next step is to define the escapement. If you have followed the directions so far, the stumps should be approximately 9/32“thick. In the finished escapement are the stumps 1/4“Often, and the front of the escapement is wider at the top than at the bottom; this helps the chips to come out more easily from the escapement. It follows that the cheeks are not on a flat surface. It is much easier to cut this shape. that describe it.
Start by peeling near the front of the escapement, tilting the chisel to create the trapezoidal shape. Work gradually backwards; when you are almost at your layout lines, switch to crossed sections to bring the stumps to their final thickness. A 1/4“The chisel held against the stumps is a practical guide to assessing whether the stumps are the right thickness. Cut a little from here: if the stumps are slightly thicker or thinner than 1/4“, Or if they taper slightly, it doesn’t matter – the plane will work just as well.
When you are satisfied with the shape of the escapement, finish the bed and breast. Do the breast first – it is almost inevitable that a few chisel strokes will hit the bed while you work the breast. Since the precise angle of the breast is not so critical, just hold on to the layout line with a chisel, then clean up with a float (or use the beveled chisel scraper).
Finishing the bed requires a different approach. Use your floating edge and make three or four saws on the bed – two on the sides and one or two in the center. These kerf should simply hit the lines of the top and sole layout. It is essential that the float does not swing up and down while you do it; the bottom of the kerf must be as flat as possible. When finished, chisel most of the waste between the kerf, then finish with a bed float or beveled chisel scraper.
Now look at the bed to see if it is twisted or has obvious problems. Slide the cutting iron (without the iron) all the way down (the mouth at this point should be too narrow to allow the cutting edge to protrude from the sole). Check if the blade swings. Holding the blade firmly on the bed with one hand, try sliding a .001 ″ feeler gauge through your mouth between the blade and the bed, then try the same thing on the top of the plane. Correct any problems by floating or scraping the high points. In the event of problems, it is now easier to fix them than when the slot is in the way.
Keep in mind that the bed doesn’t have to be perfectly flat; the cutting iron only needs to make good contact at the top and bottom of the mortise, so a small concavity in the middle is fine. What you don’t want is convexity or twist.
When the bed looks satisfactory, cut the slot for the cylinder head screw. The slot has to be generous 1/16“Wider and deeper than the screw. It should be about 2” long, but the precise length will depend on the iron. Just make sure the slot is long enough that the screw doesn’t touch the bottom when setting the iron for a heavy cut.
There are a couple of ways to cut the slot. If you have a drill press, you can extract most of them with a Forstner bit, then finish with a chisel. If you’re without a drill, use a rear saw to define the walls of the slot, leaving some tearing later (and not cutting past the bottom of the slot).
Define the bottom of the crack with a pair of good chopsticks with the hammer on the chisel, then cut the bevel down to remove most of the waste. Finish the crack by chamfering.
Next, finish the wear surface. The easiest way to do this is with a chisel and a peeling guide. Take a piece of scrap about 2 “thick and cut an 85 ° corner on one end. Attach it to your layout line at the front of the mouth. Make sure the corners of the block go back to the bed, not the breast. So jog. Try to open your mouth about 1/64“- you will open it a little more when you adjust the bed and flatten the sole.
The final step here is to taper the bottom of the stumps. This cone starts at the top of the wear and ends around 1/16“Above where will be the highest point of the iron (usually 5/8” for 3/4“Above the sole). Without this cone, the chips would be introduced into the stumps and immediately block the mouth. (If you are wondering why the wear surface must be so high, that’s why.) For a clean mortise design, you want the abutment cones begin at the top of the wear and the tapering angle is gradual – somewhere between 20 ° and 30 ° – so that the chips crumble easily as they squeeze between the wedge fingers and pass out of the escapement.
I cut the taper of the stump by holding the plane in a vertical position in a vice and nibbling it with a chisel held at about 25 ° vertically and adjusting it as needed. I always chop with light and controlled taps to avoid guiding the chisel on the sides of the mortise. Clean the remains by reaching through the mouth with a narrow chisel. Congratulations; you’re done with the mortise.
Tuning and stump wedge
It is important that the opening for the iron and wedge is symmetrical, otherwise the wedge will be lopsided, which can cause adjustment problems. It is easy to adjust the dies with a test wedge. Thickness of a piece of scrap 5/16“And cut out a wedge of 10 °. (Why 10 °, and not 9 ° as I used before? The double iron has about 1 ° of taper.) With the plane on the bench, release the assembled double iron in position and press test wedge on one side, finger tight. Make a pencil mark where the wedge meets the top of the plane and repeat on the other side.
Now you know which side has the largest opening, so start on that side and use the float to tuck in to perfect the corner. A .001 ″ feeler gauge, inserted between the test wedge and the abutment, is useful for checking the angle. When you have the right angle, draw another mark to indicate the depth of the opening, then tune in the other side until the angle and depth match.
Now for the wedge. Take the test wedge and make a 1 “mark above the previous mark (where the test wedge meets the top of the plane). This gives you the thickness of your wedge in white. The white should be flat and square. and just wide enough that one end will begin to insert itself into the mouth.
To arrange the primary angle of 10 °, use the test wedge (boy, that thing is useful) to write the angle on one side. Move the line to the other side with a square, then write the angle with the test wedge again.
For the production of production plans, I use a bench saw template to cut the corner, but if you only make one, hand sawing is faster and safer. I saw this angle the way Robert Wearing sees a tenon: make a superficial cut through the fine grain, then I saw on a diagonal on both sides and I end up with the cut straight down.
So, plane up to the lines with a little smoother plane or block. If you hold the wedge in a vise, the bottom will flex slightly because it is thin, so I prefer to keep the wedge empty in a support device like the one shown on the left. Alternatively, you can lock or screw the top of the wedge onto something (right now your wedge should be 1/2“A 1” longer than its final length).
At this point, your attachment plan will vary depending on the type of iron you have. If yours doesn’t have a die sticking out from above (thankfully), go directly to the section on the iron litter. If you have a dice, you will need to create one. Start by cutting a notch from the bottom of the wedge which is approximately 11/8“Long and fat 1/16“Wider than the cast iron nut. This will leave two” fingers “around 5/8” largo. Questi saranno eventualmente tagliati a circa 1/4“Largo, ma lasciarli grassi ora li renderà più facili da piallare.
Quindi, adagiare il cuneo sulla parte superiore del ferro da stiro e determinare la lunghezza della fessura. Deve essere abbastanza lungo da consentire alle dita a cuneo di raggiungere il punto più alto del ferro da stiro più circa 1/4“. Su questo piano, lo slot è 23/4“. Contrassegna la fessura sul retro del cuneo e segna la sua profondità nella parte inferiore della tacca che hai appena tagliato (5/16” Qui). Kerf, quindi pareggiare lo slot come mostrato di seguito.
Ogni volta che ti stai avvicinando alla fragile estremità inferiore della fessura, sostieni l’altro lato su un gancio da banco o un pezzo di scarto, ma non preoccuparti se ti scoppi un po ‘; dovrebbe scomparire quando tagli la rampa secondaria.
Al termine della fessura, controllare l’adattamento del cuneo. Spingerlo con le dita e cercare degli spazi vuoti sui monconi. Se ci sono enormi lacune, pialla il cuneo fino a quando non si adatta meglio, ma non cercare di ottenere una misura perfetta in questa fase. Devi prima fare un po ‘di biancheria da letto.
Tradizionalmente, come mezzo di trasferimento viene utilizzato olio o fuliggine di candela. Ho usato l’olio, ma ora preferisco un’alternativa moderna: pennarello a secco. Strofina il lato smussato del ferro con il pennarello in due punti: appena sopra lo smusso e dove il ferro incontrerà la parte superiore del piano. Metti il ferro sul piano, tocca il cuneo in posizione e tocca la parte superiore del ferro un paio di volte per spostarlo un po ‘. Ora togli il ferro e ispeziona il letto.
Poiché il ferro da taglio viene lanciato dal ferro da stiro in una forma convessa, le aree di contatto saranno piccole, ma si desidera vedere una linea sottile attraverso il fondo del letto, che indica un contatto continuo. Volete anche che il ferro tocchi la parte superiore del letto su entrambi i lati della fessura del ferro da stiro. Se hai un contatto irregolare, usa il raschietto per scalpello smussato o un galleggiante per raschiare via i punti più alti. Riapplicare il marker di cancellazione a secco e ripetere il processo fino a quando il ferro non è correttamente inserito.
Quindi, montare la parte posteriore del cuneo sul ferro usando un approccio simile. Strofina il pennarello a secco sulla parte inferiore del ferro da stiro (sopra la parte curva) e sotto i bordi superiori. Toccare il cuneo in posizione, quindi rimuovere il ferro da stiro e ispezionare. Si desidera vedere l’inchiostro per cancellare a secco sul fondo di entrambe le dita a cuneo. Ricorda che le dita a cuneo finiranno 1/4“In larghezza, quindi non è necessario un contatto completo. Volete anche un buon contatto nella parte superiore del ferro da stiro. Il problema più comune in questa fase è che solo un lato nella parte superiore del ferro da stiro contatterà il cuneo, probabilmente perché il ferro da stiro o il cuneo hanno una leggera torsione. Risolvi questo problema prima di proseguire, altrimenti il cuneo non si adatta correttamente. Aereo o raschiare via l’inchiostro e ripetere fino a quando non si è soddisfatti.
Ora montare le dita a cuneo sui monconi. Piana le dita fino a quando non riesci a vedere alcuna lacuna. Quindi provare a far scorrere uno spessimetro .001 ″ tra il cuneo e i monconi. Una volta che il misuratore non si adatta da nessuna parte, ispezionare le dita per segni di bruciatura dai monconi. Questi possono essere difficili da vedere, quindi usa la luce rastrellata.
Se non vedi nulla, prova a reinstallare più volte il cuneo, posizionandolo saldamente con un martello; i monconi comprimeranno leggermente le dita a cuneo e ti aiuteranno a vedere più chiaramente i segni bruniti. Spiana o raschia via i segni bruniti; ripetere fino a quando non si vede che entrambi i monconi entrano in contatto uniforme con il cuneo.
Quando sei soddisfatto, tocca saldamente il cuneo ancora una volta, quindi traccia il contorno dei monconi sul cuneo. Segna una linea attraverso la parte superiore del cuneo dove incontra la parte superiore dell’aereo. Misura la distanza da quella linea alle punte del cuneo, dividi la distanza a metà, quindi segna un’altra linea attraverso il cuneo, tra le dita. Questa linea segna il fondo della rampa secondaria, che aiuta a spazzare i trucioli sul ferro da stiro e fuori dall’aereo. Infine, estendi l’intera larghezza delle dita fino alla parte inferiore del cuneo. Ciò fornirà un punto per iniziare il taglio della sega per le dita.
Quindi, utilizzare una sega posteriore per tagliare le dita verso il basso sulla linea che segna la parte inferiore della rampa secondaria. Quando lo fai, inclina la sega di circa 15 ° (l’angolo esatto non è critico) in modo che le dita siano più grasse sul fondo che sulla parte superiore. Questo angolo, come ogni altro angolo all’interno dello scappamento, è progettato per aiutare a evacuare i trucioli in modo più efficiente; può anche aiutare a distribuire la forza dal cuneo al ferro da stiro in modo più uniforme.
Non tagliare ancora le conicità all’estremità delle dita; lasciarli pieni 1/4“Largo fino in fondo. Quei coni sono fragili e non vuoi che vengano picchiati durante le operazioni successive.
Ora è il momento di formare la rampa secondaria. Once again, pick up your backsaw and make a series of kerf cuts from the bottom of the secondary ramp to just shy of the line that marks the top of the plane. Then pare the remaining waste with your chisel. If you have a slot for the cap iron nut, the secondary ramp will cut into this slot. Cut carefully around the slot so you don’t get too much blowout.
Now pare the fingers to your layout lines, then install the wedge and check your work. The insides of the fingers should fit flush with the cheeks; if they don’t, pare them until they do. Remember to follow the angle of your saw cuts so that the fingers remain fatter on the bottom than on the top. When the fingers look good, clean up the secondary ramp with the blunt chisel scraper. Then finish the fingers by paring away the tips until they match the tapers at the ends of the abutments.
Before you cut the wedge to length, take a look at the where the main ramp meets the upper portion of the wedge. There should be a sharp arris that is roughly 1″ above and parallel to the top of the plane. The distance is unimportant, but if it’s not parallel it may look a little funny. You can fix this if necessary by planing the top portion of the wedge until it looks right.
Now cut the top of the wedge to length so that there is approximately 11⁄2” between the top of the iron and the top of the wedge. Add side bevels adjacent to the top of the wedge. It looks nice if the angle of the bevels matches the bevels on the iron. Chamfer the edges of top of the wedge and you’re ready to move on to finishing the body.
Body Shaping & Details
Surprisingly, there is no standard shape for a coffin smoother. Nearly all examples I have seen share three general features: They are widest in the middle; they are narrower at the heel than at the toe; and there is some rounding of the heel. Within these parameters, designs vary widely.
The shape I use is nearly symmetrical, has restrained curves and a heavily sculpted heel. At the other extreme, a Victorian-era Mathieson plane I own has an exaggerated teardrop shape, with minimal rounding of the heel. Take your pick between these options, or design your own.
Once you’ve got a design you like, trace it onto the top of the plane and start cutting. If you don’t have a band saw, don’t try to cut the curve; just make four straight cuts with a handsaw to define the sides, then use shaping tools (drawknife, spokeshave, plane) to define the shape.
I refine the shape by light traversing cuts with a plane using (don’t forget to chamfer the far side to avoid spelching), then fair the curves with a bed float and clean up with a card scraper.
Like the shape of the plane, the chamfers and gouge cuts vary widely on historical examples. Planes from the 18th century have crisp flat chamfers and well-defined gouge cuts, while later planes have more rounded-over edges and indistinct gouge cuts.
Start by laying out the chamfers. Set a combination square for 5⁄32” and scribe six lines across the top and down the heel and toe. Change the setting to 3⁄8” and scribe six more lines below the top and down the sides. There’s nothing magical about these numbers – I like a slope of a little more than 2:1, but anything from 2:1 to 3:1 will look fine.
Most planemakers cut the long chamfers first, but I have always started with the stopped chamfers. Do whatever makes sense to you. Cut the stopped chamfers with a chisel, and use a stop-block to keep from cutting too deeply.
Cutting the long chamfers cleanly can be tricky due to the curved surface. I use a high-angle spokeshave followed by a gunstock scraper. Before I had those tools, I used a small plane and a file. No matter the tools, take light cuts, work down hill and stay true to your lines.
When the chamfers are done, make the gouge cuts below the stopped chamfers. I use a gouge with a radius of slightly more than 1⁄4“, which gives a stylish undercut; however, a larger radius is more common, and is easier to cut.
A nice 18th-century detail is to leave a fillet (roughly 1⁄32“to 1⁄16“) above the gouge cut, but many old planes lack this fillet. Again, it’s a matter of taste. These touches – while nice – are non-functional.
Next, lay out and carve the eyes (the teardrop shapes in front of the abutments). A quarter is handy for marking the radius. I carve the eyes with a Sloyd knife, but a chisel or shallow (No. 2 or No. 3 sweep) gouge will work.
The final detail is to round the heel. As with the other details, the heel shape can vary quite a bit. I like a sculpted heel that is a stylized interpretation of an early 19th-century design. However, many old smoothers have a pretty perfunctory rounding – just enough to keep the plane from being uncomfortable in use. The important thing is to choose a design that pleases your eye and feels comfortable in your hand.
Sole, Tune & Finish
The final step in the build is to flatten the sole. Install the iron so that the cutting edge is about 1⁄16” above the sole. Tap the wedge in firmly, pencil some witness marks across the sole, and abrade it on some sandpaper stuck down to a flat surface. Once the sole is flat, check the mouth opening.
With the iron set for a shallow cut, the mouth should be about 1⁄32“. If it’s wider, no problem; a double-iron plane depends upon the cap iron to control tear-out, so mouth size is mostly a cosmetic issue. If it’s not wide enough, grab the paring block you used earlier and pare the wear a bit. Then sharpen the iron and take your plane for a test drive.
Just about any oil finish will make your plane look great: Watco Danish Oil, Minwax Antique Oil Finish and Tru-Oil Gun Stock Finish are all popular among planemakers. I avoid using finishes that have a lot of varnish in them inside the mortise. A coat of wax will protect the outside of the plane, but don’t get any wax on any of the mating surfaces inside the mortise.
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