Make a High-Angle Smoothing Plane
Thursday 04 February 2010
David Barron continues his toolmaking series by showing you how to make a James Krenov-style plane
I have been making hand planes for a number of years and this little smoother is one of the most useful. Unlike metal planes the hard wooden sole will glide over the work. Indeed it becomes more slippery with use. The high angle, in this case 57 degrees, will plane most woods without tearout and the very thick blade will eliminate annoying chatter. Shaped for maximum comfort and feel, it is very easy to use.
This style of plane was championed by James Krenov and, although I have tried a number of different making methods, I have found his way to be the best.
Before starting the plane you need to have the chosen blade to hand. Mine are made specially by Darryl Hutchinson and are 38mm wide by 6mm thick by 75mm long and have no chip breaker due to the high bed angle. They are top-quality tool steel, hardened to Rockwell 62 and cryogenically treated. The top is rounded for comfort.
Commercially made blades are also freely available as spares, e.g. for the Lie Nielsen 97 and a half chisel plane and the Veritas edge-trimming plane. Of course, old cast steel blades can be cut down to make, with a bit of work, excellent, cheap blades. Importantly, the blade must be short, thick and not too wide.
Suitable plane-making blanks are easily found from suppliers of turning blanks. 75mm square is the ideal size and bubinga (Guibourtia demeusei) or goncalo alves (Astronium fraxinifolium) are good choices, being hard, heavy and usually kiln dried.
I always try to use quarter-sawn stock for maximum stability and minimum dimensional movement across the width of the plane, photo 1. I add a 3mm sole of palo santo (G. sanctum, lignum vitae family), which is also quarter-sawn and provides the ultimate in wear resistance and smoothness. However, this is far from essential with such hard woods and is probably best omitted for a first attempt.
Whichever method is used, the grain must be oriented to run with the direction in which the plane will be used, photo 2.
Having stuck on the sole with polyurethane glue, the blank is planed absolutely square to 60mm wide by 75mm high and cut to 250mm in length. The width of 60mm is right for a 38mm blade but needs to be adjusted for other widths, photo 3.
Marking out shape
The shape of the plane can now be marked out, along with the 57 degrees bed angles which are squared across the base of the blank, photo 4.
The position of the beds and the gap that is left for the mouth depend on the thickness of the blade being used. For a 6mm blade I leave a gap of 5mm which is opened up to final size later. Reduce this for thinner blades.
The holes for the cross pin and the locating dowels are also marked and these are drilled next with an 8mm lip and spur bit on the drill press. Make sure the drill bit is exactly 90 degrees to the table or this will cause trouble later, photo 5. All holes are drilled right through the blank and it is important to back up the cross pin hole to avoid unsightly tearout. The position of the cross pin again depends on the thickness of the blade but a height of 30mm from the base is about right.
Cutting cheeks and beds
It is now time to cut off the cheeks on the bandsaw, and again it is vital that everything is absolutely square, i.e. blade and fence to the table, photo 6. Mark the end of the blank to leave a 40mm centre piece (2mm wider than the blade) and two 8.5mm cheeks, 1.5mm being lost in the bandsaw kerf.
If you use a sharp blade and go slowly the finish will be very good and require little cleaning up with a hand plane, photo 7.
Re-mark the bed angles on the centre section using the squared lines on the base as reference, photo 8. The beds can now be cut on the tablesaw, with the fence set to 33 degrees (90 degrees minus 57 degrees), photo 9. Again make sure the saw blade is exactly square to the table and cut to the waste side of both lines.
I like to curve the front bed to allow easier shaving removal but this is not essential, photo 10. I made this cut, using a narrow blade on the bandsaw, and cleaned it up with a bobbin sander.
Making cross pin
The last thing to do before glue up is to make the cross pin. Plane up a piece 13mm square and cut to 2mm less than the width of the plane, in this case 55mm.
Mark the shoulders 8mm in from each end, leaving the centre part at 39mm which is 1mm less than the centre section to allow for rotation.
Use either a chisel and files or a straight-sided plug-hole cut and a simple jig to fit the 8mm holes, photo 11.
The top two corners of the cross pin are then rounded over with a block plane to allow more comfortable access for shaving removal.
Just before glue up I chamfer the inside holes for the locating dowels - not the cross pin. This ensures there is no small obstruction to the mating parts and is good practice when using dowels in furniture as well.
To ease removal of glue squeeze-out, I also finish the exposed inside surfaces with shellac and wax.
Finally, cut the dowels down to 25mm in length so that they do not protrude when knocked into each side of the dowel holes.
I apply yellow glue to each surface and knock in the locating dowels to reassemble the blank. The cross pin must be included in the glue-up as it cannot be added later.
I clamp up using closely spaced bar clamps placed alternately across the blank, taking care not to put pressure across the centre void. If you do not have bar clamps, other clamps can be used but cauls will have to be made to ensure even pressure.
Curves and profiles
After leaving overnight to cure thoroughly, the glue squeeze-out is cleaned off with a cabinet scraper and the curves for the front and back are marked out on the base, photo 12. The curve for the front is made for a right-handed grip but can easily be reversed for lefties.
The cuts are made with a sharp three-eighths of an inch blade on the bandsaw. The side profile is then redrawn on the front and back and the profile cuts made.
Rough shaping of the rounded rear can be done in a number of ways such as by using a draw knife, spokeshave or Arbortech grinder. I favour using the bandsaw as advocated by James Krenov and Sam Maloof, photo 13. This method is quick and can be surprisingly delicate. Indeed the planes that Krenov made are left unfinished straight from the bandsaw. While this technique is inherently dangerous and not to be recommended, there are certain precautions I take which make things safer.
1. Use a narrow blade with 6 teeth per inch
2. Keep part of the work in contact with the table
3. Take only small cuts and go slowly
4. If the blade is grabbing the work, I back up and take a finer cut
5. Keep my hands well away from the blade
Final shaping is done quickly with an Auriou No. 10 rasp followed by a disc, bobbin and random orbit sanders, photos 14-16. Final hand sanding with 180 grit and 240 grit softens the edges and gets rid of any machine marks.
After removing all traces of glue squeeze-out from inside the throat it is time to make the wedge. Unlike a number of other plane makers I prefer to make my wedges from a more supple wood than the dense plane body.
Ash (Fraxinus spp) and oak (Quercus robur) are good choices and the Japanese have long favoured the latter for its ability to hold blades firmly.
The shape of the wedge is also important for maximum grip, having a slight curve, photo 17. This applies pressure on both edges of the cross pin and leaves witness marks on the wedge.
For final fitting of the wedge, gently remove material with a cabinet scraper until the two lines run across the full width.
It is a good idea to apply a finish at this stage and this is a matter of personal preference - Krenov would leave the wood bare.
As bubinga has reversing grain which can appear blotchy when oiled, I decided to apply a couple of coats of shellac. This also helps to preserve the nice red colour of this particular batch.
I followed this with three coats of Osmo Hardwax Oil applied thinly with a rubber, cutting back with 600 grit before the final coat.
Flattening the sole is next and this is carried out with 180-grit sandpaper glued to a flat surface.
The blade and wedge should be firmly installed before starting with the blade retracted a little. This should be done slowly and deliberately to ensure a flat base.
Most books and articles I have read do not emphasise the importance of care at this stage. It is almost inevitable that if a plane is gripped in both hands and rubbed back and forth that a convex surface will develop in both the length as well as the width - this is disastrous for successful planing, photo 18.
The best grip I have found is to hold the plane in the middle with one hand, which means reversing the plane and placing one hand over the blade. The plane is then pushed with elbows locked, in a slow deliberate manner using short strokes.
At the end of each stroke stop the plane and carefully lift off the sandpaper, repeating this sequence until there is an even scratch pattern across the whole surface.
Move on to 240 grit to refine the scratch pattern, taking just as much care with the technique. It is not necessary to use any finer grits as in use the base quickly develops a polished surface. The base can be finished with raw linseed oil or paste wax.
The final step is to open up the mouth, which again needs to be approached with care. Although a wide mouth can be rescued with a patch, it is a lot of extra work so take the time to get it right in the first place.
If everything has stayed square the easiest way to open up the mouth is by using an engineers square and a razor-sharp knife and chiselling back to the line. This may take three or four goes to creep up to the desired mouth opening, which should be tiny, photo 19.
Keep checking the blade as you go and if you find it is slightly skewed then adjust the angle of the mouth to suit. Of course the final mouth fitting needs to be done with the blade fully prepared and sharp.
The rear of the mouth also needs to be opened by about 2mm to avoid leaving a delicate edge which would be prone to chipping. And that is it. All that remains is to set up the blade and take some fine shavings.
With the blade positioned close, the wedge is fitted with hand pressure and then the blade tapped with a small hammer. Lateral adjustments are made by tapping on either side of the blade.
Once the blade has been set for a fine cut the wedge can be gently tapped home. Further adjustments can be made although if the blade has gone too far it is best to wiggle the wedge and blade free and start again. This may seem a faff but with a little practice it is quick and, once the blade has been set it does not need to be touched until it needs re-sharpening.
Shavings from a high-angle plane without a chip breaker tend to be more concertinaed and can accumulate in the throat. However this does clog or stop the plane working, so they just need to be removed every few strokes.
The ability of this plane to handle figured woods and reversing grain and swirls around knots will soon be appreciated. It is also useful for cleaning up dovetails without tearout.
This set of 11 planes took 29 hours to complete, taking advantage of the time saved in batch production, as well as experience.
A one-off plane should take about eight hours to complete excluding an overnight glue-up somewhere in the middle, photo 20.
Maintenance of the plane is minimal with occasional sole flattening. This is most likely to be needed 3-4 weeks after making, once the plane has acclimatised to its new surroundings.
If necessary a few careful strokes on 240-grit sandpaper on a flat surface will do the job. The blade is best sharpened with a slight curve and kept razor sharp -the higher angle will dull the edge faster.