Fine drawer making, part 2
Words: Neil Erasmus
The first part of this story focused on timber selection and preparation. Here, Neil Erasmus describes the cutting of dovetails and the fitting of the drawer.
Before we start with the serious business of cutting dovetails, mortises and tenons there is a short checklist of stages that need to have been completed beforehand.
I. Drawer fronts and sides machined to correct height and thickness, allowing for wood movement.
2. Height of drawer back machined to allow for drawer slips and a step at the top.
3. A suitable groove cut in the drawer front and slips to house the drawer base (groove drawer sides if not using slips). Note the groove in the front is deeper (about 15mm) than the slips (half the thickness of the slip). The width of these grooves is l–2mm less than the thickness of the base.
Arranging the drawer parts
After machining all the drawer parts I orientate and mark their positions. An important point to bear in mind when considering their arrangement is to check very carefully for bow, twist or spring. A bow is curvature when lying face down on a flat surface; twist is when the faces resemble a propeller; spring is curvature when placed edge down on a flat surface.
Any parts that are twisted should not be used, as they will invariably cause the entire drawer to twist. If drawer sides are bowed they should be arranged with convex faces to the inside. This is done because the drawer base, once inserted, will push these sides out again.
Sand all the inside faces of the fronts and sides and both faces of the backs to final finish stage. This will depend on your choice of surface finish. I use an oil finish and sand to 600 grit, but if you wish to lacquer 180 or 240 is fine. You’ll discover a sloppy fit if these parts are sanded after the joints have been cut. I sand all these parts by hand using a hardwood sanding block, being very careful to keep the entire surface, including the edges and corners, perfectly flat. Power sanders are great for large surfaces but tend to remove more material from these parts.
Next, using a good quality sharp cutting gauge (I never use a marking gauge for dovetailing), set the cutter to desired dovetail length – this being the depth of the rebate across the end of the drawer front. This measures around 16–18mm on a standard 22mm thick front. Cut a line across the endgrain using the inside surface as the guide. This same setting is used for scribing right around the faces and edges of the front ends of the drawer sides.
Now reset the gauge to the precise thickness of the sides and scribe the inside faces of the ends of the fronts. Never scribe the edges of drawer fronts, but if you wish to cut through dovetails scribe the front face lightly.
The dovetail pins can next be set out on the drawer fronts using an angle of 1:8 or 7–8°. Set out equal half pins on either edge, being mindful of where the groove for the base is cut as this needs to be covered by one of the tails in the side. These half pins need to be as large as possible.
I generally keep dovetail centre in the range of 20–40mm apart, depending on the height of the drawer. I make the bases of the pins about Imm, just enough for one entry point for a dovetail saw when cutting the waste in the drawer sides. However. I always ensure there is at least one pin in the centre irrespective of the height of the drawer. These drawers can be as small as 25mm in height.
Mark the pins with a small scribing pin like the one you’ll find in a combination square. These marks can be highlighted with a fine white or black pen depending on the timber used. Square the pins across the inside face to the scribed line.
Using a fine-toothed Western or Japanese saw, cut just on the waste side of the lines. Cut right down to the two lines across the corner of the drawer front, cutting with the grain: with a Western saw clamp the drawer front upright in the vice; if using a Japanese saw, clamp horizontally on the bench. You may wish to remove most of the waste with a small router or trimmer fitted with a small diameter straight cutter. This leaves a nice precisely cut rebate with only a small amount of material in the corners to chisel out. Don’t undercut these rebates as many people advocate, as this only makes for a sloppy fit. If necessary, make up a couple of straight and angled blocks to guide the chisel.
Sharp chisels are an absolute necessity and well practised grinding and honing skills are a must if you wish to achieve sharp, crisp edges, corners and flat surfaces. A sharp chisel firmly held between the middle segment of the index finger and the ball of the thumb should be able to be pushed easily across the endgrain of hardwood to remove a shaving. No tapping or hammering should be required.
The next stage is to accurately mark out the tails from these pins. Holding the drawer front vertically I clamp it over the drawer side where I need to transfer the pins to the tails. I tap the front perfectly into position with a light hammer making sure the edges are flush and the scribed line is lined up with the broad edge of the pins. Scribe the tails from the pins. Please note the scriber needs to be very sharp with a gentle taper down to its point. Regrind one if necessary. Make sure to scribe right up against the pins starting right in the corner and pulling the scriber outwards. One firm mark is all that is necessary. Highlight the marks as discussed before and if necessary square across the endgrain.
The next steps are crucial as they are the ones which will leave you with either a sloppy, perfect or over-tight joint. I always start this stage with a few warm-up cuts on some scrap pieces of the same section and species as the drawer sides. I then mark out a number of left and right leaning angles similar to the ones on the dovetails. I also cut down to a scribe line. Placing this vertically in a vice I cut perhaps a dozen or so of each, always just to the left of a left leaning angle, and vice versa. Once you are confident you are cutting right to the line every time and not beyond the scribe line, start cutting the real sides.
I find once I have started cutting these tails, I need to persevere until I have done them all otherwise I lose the rhythm and start cutting skew. I use a fine-toothed Japanese saw because it leaves the far side (which is seen outside) crisply cut because of its pull-cut nature. However, because of its slightly thicker blade I sometimes use a Western dovetail saw when I need to remove a little more material for a better fit. In these cases I cut right down the original fine kerf. Also, a Western saw is far more forgiving if, half way through a cut, you need to adjust the angle. So, a bit of East and West does the trick!
Now, for the removal of the waste. I use a coping saw whose blade I adjust to around 70° to the neck, insert into the saw kerf and wiggle down to within 2–3mm from the base of the tail. Don’t try to cut down, as you don’t want to open up the kerf. Once you have it where you want it vigorously start cutting while maintaining an angle on the blade to enable it to cut a tight radius, without wandering past the scribe line. Keep your cut about 0.5mm above this line.
Remove the waste
Cut carefully to the other side, angling the handle slightly so that if there is any over-cutting, it takes place on the inside of the tail where it is not seen. This will remove the majority of the waste.
Leave your drawer side upright in the vice position the blade of a suitably sized chisel at an angle of 10° in the ledge left by the scribe line, and gently push it halfway through the side. If your chisel feels much resistance it probably needs sharpening. With perhaps two or three cuts of decreasing angles you will have cut down to the imaginary spot in the middle which lies on the same line between the inside and outside scribe lines. Turn the side around in the vice and repeat this process from the outside.
When this process is complete, check to see whether there are any high spots between the faces. I do this by removing the side from the vice and finishing it off in my hand. You may wish to undercut slightly by a degree or so, but try not to rely on this practice.
The edges of the drawer sides where the half pins go can be entirely removed with a fine saw by deepening the scribe line on the edge with a chisel so that the sawblade may start the cut right on the line. Once all the tails have been cut, chamfer their leading corners on the inside face with a chisel. If you are making through dovetails, start your chamfer 2mm or so from the ends of the tails, otherwise they will be visible on the completed drawer.
You may check the fit by tapping a set of tails over their mating pins with the back of your hand. You will feel whether the fit is just right or not. If it feels too tight, remove gently. Never force the fit. By checking the mating surfaces you’ll see where the tight areas are by the pressure marks. I have found that the best method to remove such small amounts of material accurately is to wrap a little 320 grit paper around a thin 6" stainless steel rule and pass it through between the tails to sand off the offending microns of wood. Again, don’t rely on this method as it adds time.
Fit the back
When you are satisfied all the pins and tails are complete and ready for assembly, the next step is to fit the drawer back. I cut two or more 6 or 8mm square tenons from the ends of the backs, using precisely the same rules regarding scribing, cutting and chiselling as outlined earlier. Once the tenons are cut and cleaned up, I cut a fine vertical kerf in each one into which a small wedge is driven after assembly. The mortises in the sides are cut with a hollow chisel mortiser or, if you don’t own one, by precisely drilling a hole and cleaning up the corners with a chisel.
The drawer is now ready for assembly, I use animal hide glue because it allows disassembly if anything goes wrong, is extremely strong and won’t allow creep. And for those who can’t quite get it right, it also provides the advantage of gap-filling properties. If you need to disassemble such a joint just steam it apart as the heat will liquefy the glue again. No other modern day adhesive allows such easy reversal, however PVA glue is a good alternative.
Assuming the base grooves were cut in the slips at the same time as they were done to the fronts, all that needs to be done to these is to rout a quarter round or 45° chamfer to the top inside corner, and to cut out down to the start of the groove, a small lapping to fit over the underside of the drawer back. These can now be cut to length. final sanded, glued and clamped in place.
Join up the parts for the drawer bases, sand them and cut them to size, arranging the grain direction to run from side to side, not from front to back.
Measure the opening and cut the bases precisely to the length but deduct about 4mm from the width to allow for seasonal movement. The bases should be around 2mm thicker than the groove width so they need to be rebated from underneath to fit. I fit a slotting cutter to the router table and carefully adjust the height and fence to cut a neatly fitting tongue. This tongue needs to be the same depth as the groove, so don’t forget to increase its depth at the front. Don’t rebate the back of the base. Slide the base into place and screw in to the back. The back of the base, slides and slips should all be flush, allowing expansion into the groove at the front. Rub a little candle wax onto the tongues to ease them into the slips.
Fitting the drawer
Now all that is left to do is to fit the drawer into thecabinet. Somecareful planing and sanding should achieve this. Once the drawer fits into the carcase, close it – if it sticks, don’t force it, but pull it back out again and look for any shiny pressure marks which indicate the high spots. Remove these, try again and repeat if necessary. Apply a little wax to all the contact points, including those inside the carcase. Good luck and happy drawer making!
See the first part of this series at www.woodreview.com.au/how-to/fine-drawer-making-part-1
First published in Australian Wood Review, issue 25, December 1999
Neil Erasmus is a furniture designer/maker in Perth, WA and also teaches woodwork. See www.erasmusdesigns.com