Roubo Hollows & Rounds | Popular Woodworking Magazine
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Make these French molding plans which are essential for any hand tool kit.
Hollows and rounds are returning strongly to the world of woodworking hand tools. However, many carpenters are afraid to jump from a limited tool budget or the limited availability of old ones in good condition. Don’t let yourself stay longer. You don’t need a whole set to start anyway. The three dimensions of this article – the numbers 4, 6 and 8 – are the ones that happen to me most often. (A No. 4 cuts a 1/4“Profile, 6 cuts 3/8“And 8 cuts 1/2“.) After making a pair or two, you may find that you never need another dimension to meet your business needs.
I will teach you how to build your planes, just like the first craftsmen did. They were carpenters, not professional planemakers, so they built planes with tools that were readily available in their chests. In other words, tools that you probably already have.
André-Jacob Roubo shows and describes these plans in his 18th century masterpiece “The art of the menu”. What I will show you reflects the construction of Roubo’s plane combined with British / American style and proportions. This way, your new planes will fit perfectly into your British-style toolbox and will likely match many of the planes you already own.
While you can build a plane with any type of hardwood, some woods are clearly the best choice. Traditionally, western planes were mainly made of beech. Other choices historically include yellow birch and fruit trees such as apple and even pear. If you intend to work hard wood with your worktops, choose a wood with diffuse porosity like the ones mentioned.
A non-traditional wood that is worth considering is hard maple.
Avoid porous ring hardwoods like oak because soft early growth ring layers can experience unwanted effects once they start to wear out with use.
Regardless of what you choose, select 4th stocks for seasonal stability.
Since many diffuse pore woods are often difficult to find in semi-finished products, it is possible to find simple-cut 16/4 material that can be cut into quarter-billets. Sometimes you can find large sawn boards that have been cut close to the squared orientation on the outside edges of the board.
After selecting the stock, prepare two empty spaces for the bodies for each dimension of the plan: one for the recess and one for the round. The empty spaces are all 31/2“Wide x 91/2“Long. The thicknesses will vary: 3/4“For the 4s; 15/16“For n. 6s; and 11/8“For the 8s.
You will also need it 1/8“-Space thicknesses for O1 tool steel blades (ground surface on both sides) to adapt to the profile dimensions (two per set). Tool steel is available in small lengths from numerous online suppliers, including McMaster-Carr (mcmaster.com) and metals online (onlinemetals.com).
The final length of the blades shown here is 8 “(7 3/8“Also works for Roubo-style planes).
Time spent well
Making a mask is not how I like to spend time in the store, but this saw guide is worth the investment. Consistent bed and breast angles are at the heart of effective floor plans and this mask will help you achieve this.
Any stock that hasn’t completely cut as flat material should work well. Arrange the corners according to the following drawing, then cut freehand with a rear saw. Don’t worry if your angles aren’t perfect; any changes will be processed later in the wedge adaptation process. Try to align the 55 ° side of the 90 ° rail in the best possible way. This will simplify the assembly of the wedge later, as you will see.
Now align these cut surfaces with an airplane. For the fence, choose material that will protrude from the bottom in all directions. Screw this on the bottom. Use the slanted surfaces of the mask body to guide your saw in cutting the fence to match their respective angles. Build these surfaces with an airplane.
Nut – Triangle style
Creating the heart and soul of this plane is not much more difficult than creating a dice … just a triangular dice.
Orient the body flat so that the grain flows from the tip to the heels. Arrange the width of the table blade (1/4” 3/8” or 1/2“, Depending on the plane of the dimensions you are making) at the top and bottom of the body of the plane from the side of the escapement.
Secure the body between bench dogs, with the escapement facing up and the sole facing you. Position the saw guide on the body so that the side of the corner of the bed (55˚) is facing left and the fence is pressed against the sole.
Place the saw guide 33/4“Back from the tip, then subtract the thickness of your saw. Secure the rail in place with a catch, then adjust the cross saw against the rail and cut the layout line for the flat blade.
Turn the guide over from left to right so that the side of the breast angle (65.5 °) is now facing left. Place the forward guide of the kerf at the corner of the bed on the nearby sole 5/32“. Since the breast cut is not at 90 ° – it is inclined by about 3.5 ° – it will not create an opening of constant width. Therefore, measure forward 5/32“To the depth of the cut of the previous saw. So, 5/32“It will be the maximum width of the opening on the sole.
Now dig the material between the two kerf up to the blade depth line. You can use a 1/8“Chisel or, better yet, a specialty 1/10“Chisel to be inserted (Lie-Nielsen brings a nice one) to go through the opening only. Follow with a narrow blade in the plane of the router to obtain a constant depth. If you do not have a router plane, you simply have to cut the nut slightly in so that the blade and wedge fit snugly into the top and bottom.
Don’t open wide
Since the breast is tilted, you will need to remove additional material so that the blade can pass through the sole.
Use the piano blade as a guide to mark the amount of material to be removed. Position the blade along the angle of the bed and let it protrude from the sole. With your amazing knife, mark along the front of the blade through the breast portion that blocks the passage of the blade through the sole. Transfer this line down and square across the sole. Use a chisel, working from the side and up from the sole, to remove this material. Be careful not to remove too much. You will finish the opening later.
The lower and upper limit of the escapement should be approx 1/4“And 1 1/4“Respectively from the sole. I find that an 18 mm gouge, n. 7 functions well to sculpt it. You want the shape to look like an almond, with the widest part towards the sole. Do not carve up to the depth of the breast wall; leave a narrow area between the bottom of the escapement and the breast wall so that the tip of the wedge returns uniformly towards the opening of the mouth.
Create a wedge using fourth material; you want the sides of the spokes to be exposed to the sides of the wedge, just as they are on the flat body.
Size your wedge 71/4“Long (or long) of 1 1/4“Often, for the width of the blade, more or less 1/64“. (This extra width will later be sanded flush with the side of the plane.)
Mark a taper of 11.5 11 along the length of the piece and an inclination of 3.5˚ over its entire width to adapt to the angle of inclination of the breast. Place the piece in the vice and tear off the wedge. If your stock has been long enough, save your cut to make a second wedge.
Align the edges of the wedge with a small plane of the shoulder and check that the angles are correct (90˚ for the bed side of the wedge and make sure that the side of the breast corresponds to the angle of inclination of the breast in the body). Small adjustments can be made to the angle of inclination of the wedge by rotating the iron in the body of the shoulder plane so that it performs a slightly deeper cut on the side that requires more material removed.
Straight like an arrow
You are now ready to start preparing and shaping the iron. Flatten the bottom 21/2“About the front and rear blade. Do this by rubbing it back and forth on a 3” wide strip of 120 # grain aluminum oxide sandpaper adhered with spray adhesive to a flat surface. (A granite surface plate or even the bottom of the sole of the jointer plane makes an exceptional flat surface.)
Use enough pressure to let the paper do its job, but don’t press too hard or you will round the edges excessively. You are done when you get a consistent scratch pattern on both sides.
The blade is now ready for the wedge assembly test.
Adaptable in all the right places
This is where the tire meets the road. A well-adapted wedge and iron are half the battle to create a perfectly functioning plan. The key is to make sure that the wedge has a perfect adherence on the tip and gradually decreases its adherence as it moves away from the tip.
So basically, the wedge will have a slightly more acute angle than the bed and the corners of the breast. If the bed and breast have an 11.5 ° angle, the wedge would be slightly less than 11.5 °. This will ensure that the blade is always securely attached to the place where it is most needed: the closest to where the cutting action will take place.
A good indication that the wedge has a slightly more acute angle is that when placing it on the surface with hand pressure, there will be a small gap between the wedge and the corner of the breast at the top of the surface. If the space closes once the wedge is hit with a flat hammer, then you’re almost perfect. A thin space at the top of a wedge and a snug fit at the bottom is preferable.
To achieve this, make sure that the areas of the bed and breast are free of any loose fibers in the corners. Place the blade into the body and test the wedge. Determines whether the wedge angle should increase or decrease.
Adjust the wedge by positioning the flat wedge on the work surface and grasping it with one hand. Use a sharp shoulder plane to make tapered cuts along the length of the non-inclined side of the wedge to increase or decrease its angle.
If the fit is too tight at the top, for example, make overlapping cuts starting with short steps on the heel of the wedge and gradually lengthen the steps until you make a full-length step up to the tip.
You are now ready to shape the sole. You will run the round first, because you will use it later to shape the empty profile. Place the “round” profile on the toe and heel, as shown in “Elevation” (page 25) and in the photo above.
Note that the drawing shows the central points for using a compass to arrange a 3/8“-Radius arch (which corresponds to n. 6). A compass is the most accurate way to do this and keep both ends of the plane profile coplanar. It is important that the profile does not twist or that your plane is not functioning properly.
Now give the profile some space along the blind side (the side without escapement) of the plane body by hitting an angle of 30˚ upwards and away from the corner of the profile. Go ahead and remove about 90 percent of this bevel with a plan so that the round part is easier to cut.
Since you don’t have a curved profile plane that matches your radius (otherwise you wouldn’t, right?) You can use any plane with a flat sole to cut the profile. You will end up with a faceted surface that can be smoothed with a few light passages of # 220 or # 320 grit sandpaper. Remove only the tips of the facets and no more.
Before planing the profile, insert the blade, remove it slightly from the mouth (so as not to cut it) and insert the wedge. This will introduce any stress on the plane from the wedging action before cutting the profile.
Now fix the body in your vise with the sole facing upwards and the toe towards you – but fix it only on one side of the heel section to avoid distorting the plane along its length (which could detach the profile once removed from the vice). I find that the opening of the rear vice works perfectly. Plan the profile from toe to heel by working with the grain.
Complete the profile by removing the rest of the side bevel with a manual plane. Secure it on the bench between two bench dogs as before, and flatten it to the width of the profile. Be careful not to remove the side of the mouth down to the edge of a knife; this would weaken this point and cause the chips to jam in this area and would be a constant problem, so leave it a little heavy.
Place the driver’s disposition fluid on the bottom edge of the blade. Hook the blade into the plane and place it in the vise of the tail with the sole raised. Use a scribe to trace the profile of the sole on the blade. Grind the profile, then grind a detail of your choice (or not; it’s optional) on the heel of the blade.
Roubo shows a sneck on his irons: a small piece of flag-shaped material on the heel that allows you to retract or remove the iron with a light hammer blow upwards. (The alternative method of removing the iron is to hit the top of the handle on the tip with the non-metallic side of a plane adjustment hammer.)
Snecking can be performed as easily as a little of the steel is notched on the side of the iron near the heel. Alternatively, you can replicate Roubo’s sneck style by selecting at least one piece of steel 1/8“Wider than the required blade width. Grind the bottom to the required blade width leaving the last 11/8“About the part of the heel for the whole width.
To grind the hollow profile, I use a narrow metal cutting wheel mounted on my grinder.
Heat treat O1 tool steel is simple. In short, bring it to a critical temperature, turn it off with vegetable oil, then temper it in a toaster or in a normal kitchen oven for an hour at 400 °.
Hardening steel is the easy part; minimizing deformation is another. The road to success is to heat the metal evenly. Creating a fence with something like firebrick will help you achieve this.
Heat the steel slowly using a simple MAPP gas torch. Warm it up more slowly than you think you should. If one part is hotter than the other when you turn it off in the oil, it will deform. Then heat slowly.
There are some methods for determining when you have reached the critical temperature. Avoid relying on color because ambient light will affect the color you see. Just as a torch appears brighter at night than in daylight, so even the color alone in changing light conditions can be deceptive. The easiest way to check that you have reached the critical temperature is to use a magnet, since O1 tool steel loses its magnetism at about this temperature. The maple stick shown below has a rare earth magnet glued to the end; it is a simple tool to safely control steel when it reaches critical temperature. Periodically remove the steel briefly from the flame and check it with the magnet.
Another option is to look at the quality of the steel surface. It will change when the critical temperature is reached because carbon begins to flow inside the steel and some decarburization takes place on the surface, thus changing the appearance. It can be described as “sweating” of steel or with a “red” appearance. Accompanying this change will be a significant increase in the “brilliance” of steel. In other words, instead of seeing a particular color change, you would simply see that the color becomes more radiant.
Once the critical temperature is reached, extinguish the steel in oil by immersing the blade vertically downwards, without tilting it from one side or the other. Now go immediately to the oven to temper for 400 hours for an hour.
Boxy or Curvy?
While the blade is tempering in the oven, it takes this time to round the heel of the handle on the body. A carving gouge is the perfect tool for this. Just place the body on one side and align it on the heel. If desired, cut the profile of the tip or leave the square, then smooth the upper edges and perfect the surfaces.
After the blade has been tempered and cooled, flatten it again to remove any distortion from the heat.
Start with # 120 grit as before, then follow with 180 to # 320 grit sandpaper on the cut face, then jump onto a # 1,000 grit stone.
Stop there and put the layout fluid on the face of the blade and write the profile on the end of the blade as before. Now grind and sharpen the edge.
To sharpen the blade for the cavity, I prefer to use a ceramic sandstone.
Clear your throat
It is time to perfect the opening of the mouth and, at the same time, cut the angle of inclination of the wear.
Once again wedge the blade into place, but leave it extended beyond the sole for a short distance. Using a mechanical pencil, strike a line of the mouth on the sole by resting it against the blade as a reference while drawing the opening line of the mouth.
Using the mouth opening line as a reference, mark the wear bevel angle (see “Profile” on page 25). It will be located approximately halfway between the bed and the corner of the breast. Now, cut the wear with a chisel, using a combination of side and bottom cuts.
Using the same gouge as before (18mm, no. 7 sweeps), shape the tip of the wedge so that it corresponds to the curve of the escapement. I find that a spoon carving knife is a great tool to refine the shape.
Make some test cuts (obviously working with wheat). Make sure that the sole is straight and that the blade profile corresponds as closely as possible to the sole.
If you find that the shavings continue to get stuck in your mouth, it is probably due to one (or more) of the following: a matte blade; a blade profile that does not fit well or extends too far from the blind side; a mouth too small for the depth of the cut; a wedge tip that extends in the bevel of wear; or a non-adherent wedge tip, which creates a space in which the chips fit together.
It may be necessary to slightly adjust the wedge angle to compensate for a slight thinning of the blade edge during flattening and sharpening.
Now bring the thickness of the wedge flush with the sides.
All that’s left to do is cut the final wedge profile with your hat saw. The carving gouge n. 7 by 18 mm will work well for cleaning up some shapes.
To make the match hollow, follow all the above steps up to shape the sole. For this, you will use your new round top to cut the empty profile. If you have been careful to make both bodies of the same identical thickness, you can align the profiles for cutting by positioning both planes on their sides and sliding the round to plan the cavity.
I finish my planes with a coat of Tru-Oil Gun Stock finish. Let the finish harden completely unassembled to prevent the parts from getting stuck. Put a light layer of jojoba oil on the blade for rust resistance and ease of adjustment.
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