Putting the Carcass Before the Drawers

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Putting the Carcass Before the Drawers:
Scott Horsburgh shares a technique for creating piston fit drawers.

Scott Horsburgh shares a technique for creating piston fit drawers


I have many woodworking heroes and my recent introduction to Instagram has led me to discover many more. This desk was inspired by the wonderful desks made by New Zealand maker David Haig and English maker Henry Smedley. I had no commissioned work to undertake so I had an opportunity to make something special for my showroom. This desk and chair were the result. I have received advice from both David and Henry on various methods used in the making of their desks. Along the way I also asked questions of other makers from around the world and received some wonderful advice. I thank you all for your time and the sharing of knowledge, which really does make woodworking a lifelong learning experience.
This article will mainly focus on the carcass preparation required for fine fitting drawers and then some minor details of making and fitting the drawers. I will focus on the four small upper drawers as they are fitted to the carcass sides. The large lower drawer in the main desk body has been fitted using the technique described by Simon Jones in F&C 245. It was the first time that I had tried that method and for large drawers the result is excellent.
In 1994 while working in London, I went to an exhibition of fine furniture where I was mesmerised by a walnut (Juglans regia) chest of drawers made by Alan Peters. I had never seen such a beautiful piece of furniture. The lines, crisp joinery and immaculate finish were incredible. I stole a quick feel of the drawers and stood back in amazement. At that point I was a young chartered accountant who was a hobbyist woodworker. That day changed my life and the following year I commenced a long course with David Charlesworth at his workshop in Hartland, Devon to see if I could improve my woodworking. David is a lovely man, a meticulous craftsman, a great teacher and very patient. I consider the time that I spent with him to be very special. To be able to learn from a highly skilled craftsman in their own workshop is a gift. David is a pretty calm sort of a bloke, but the only time I ever saw him a little bit frazzled was when I told him that the rear opening of my small carcass was 0.25mm wider than the front opening, instead of the desired 0.2mm wider. I thought to myself, ‘calm down David, it’s only a twentieth of one millimetre’. That was before I knew the impact that such small dimensions could have on the fit and feel of fine drawers.

Carcass preparation
The long horizontal shelf in the upper section of the desk is joined to the sides with a 5mm tenon in a groove. The shelf was a little too thin for me to use a sliding dovetail but as the sides of the desk are securely joined 100mm above (through dovetails) and 110mm below (Dominoes), a tenon is fine. All of the other components within the upper section are housed with 3mm tenons within grooves.
When preparing all of the shelf and drawer carcass components for the upper section of the desk, some time taken in accurate stock preparation and accurate marking out can save you a lot of time further along the way. I mark out all of my drawer openings to be perfectly square. I rout the grooves using a handheld router running up against a secure fence. I planed all of the surfaces flat and true and then routed the tenons on the router table. The interior sides of the drawer carcasses were waxed and buffed.
The external sides were oiled. I routed out for two drawer stops per drawer.
After all of the pieces were glued in place I flushed the front edges of all of the pieces with a block plane and then a light sand with 320 and 400 grit sand paper. I was now in a position where I could check the four drawer openings for their dimensional accuracy.
David Charlesworth explained to me that he liked a snug drawer to tighten ever so slightly when pulled out to ensure it wasn’t removed too quickly and all of its contents spilled onto the floor. David achieved this with slightly tapering carcasses where the front sideways opening was slightly narrower than the back – this need only be 0.2mm difference. This is very easy to achieve when you can take a couple of fine shavings off the end grain of carcass tops and bottoms before marking out for joinery. However, in this case it was a little more difficult. Rather than try for a slightly tapered carcass, for these drawers I strived for a perfectly parallel opening from front to back.
I used a piece of MDF that I taped at each end to avoid scratches. This MDF was cut to fit snuggly into the front drawer opening. I wanted to be able to slide that piece from the front to the back very snuggly – no racking or binding or being sloppy from side to side. When sliding the MDF back you can feel everything. If it tightens too much, mark the area so you can remove a fine shaving with either a block plane or some fine sandpaper on a block. This process is crucial as it will ultimately determine the fit of your drawers. For these drawers, as mentioned above, I wanted the carcass opening to be perfectly parallel. If it opened slightly towards the back by a fraction of a millimetre (about 0.1mm) I was OK with that. Because the openings are quite small I used some 320 grit sandpaper on a block to remove any areas that tightened too much. Once I was happy with the carcass dimensions, it was time to commence making the drawers.

The desk interior awaiting calibration

Checking the drawer carcass dimensions with a block of MDF

Making and fitting the drawers
These drawers are in a fairly traditional style with single lap dovetails at the front and through dovetails at the rear. When selecting wood for the drawer sides, quartersawn wood is the best choice. I also look for mild, straight grain so it is easy to plane the drawer to fit. The sides, once squared off at each end and planed with a face side and face edge (inwards face and downwards edge) were shot to fit snugly into the vertical opening. To fit the drawer fronts, the sides were slightly tapered back so that the front almost wedges in very snuggly. The drawer backs are fitted from the drawer fronts.
I then marked out and cut all of the dovetail joinery. Before gluing the drawers up, I finished all internal surfaces by taking a very fine cleaning shaving and then a light sand with 400 grit sandpaper.
I masked off all of the joinery and also the area where the drawer slip will be glued. I ensured that the groove was also routed in the drawer front to accept the top portion of the drawer bottom and the small tenon on the end of the drawer slip.
I also rounded the top of the drawer back and tapered the last 15mm of the upper back end of the drawer sides to allow for easy entry into the carcass. Once all these jobs were complete and the required areas were masked, I finished the interior surfaces with wax. I was now ready to glue up the drawers. I apply glue using a small paintbrush, mainly to the long grain areas but also a little on the end grain for good luck. I tapped the joinery home and ensured the drawer was square. I do not clamp drawers, I ensure they are tight and square and then leave them to dry.
The next day, I planed the drawers to a preliminary fit without the drawer bottoms. I do this mainly to flush joinery and remove glue squeeze-out. This is left as a tight fit. Before I commenced planing the drawers to their initial snug fit, I flushed the bottom of the drawer and also planed the top of the drawer to allow for
the wet weather tolerance. If you leave these tight and start to plane the sides first, it will tend to feel continually snug and give you a false sense of the fit. You will continue to plane the sides until you realise the firmness is due to the vertical fit and not the horizontal (sideways) fit. I’ve done it and it is annoying when you realise you have planed too much off the sides.

Fitting the drawer components into their respective openings

Shooting all four edges of the drawer components

Fitting the drawer fronts into their openings

The drawer components fitted and ready for joinery

The internal drawer sides taped and ready to be waxed

Groove routed in the drawer front for tenons on the base and slip

My method for securing drawers while planing for their initial fit

Making drawer slips
I like drawer slips. They serve a very useful purpose and can give drawers further fine detailing. The drawer sides for this desk are 5mm thick. Using a drawer slip greatly increases the running width of the drawer. These slips are 17mm wide and 11mm high. Therefore the drawers are now running on 22mm sides instead of 5mm. When fitting drawer slips, if you ensure that the grain on its underside runs the same way as the grain on the underside of its drawer side, then planing them flush is a breeze. These slips have a small tenon that fits into the routed groove in the drawer front.
At this point I had previously glued on the drawer slips and then fitted the drawer bases. However, this time I tried something different based on an Instagram feed written by Brisbane maker Roy Schack. Roy described how he cuts the drawer bottom square and routs the tenon to fit the slips and to fit the groove routed in the drawer front. He then fits each slip to the drawer bottom and places the drawer over the top and centres it. A knife line can then be gently cut into the slip running along the inside base of each drawer side. You then shoot the slip to the line and when glued in place, the base will slide in for the perfect fit – I like this method a lot. So that is exactly what I did. I don’t know why that method didn’t occur to me before as it is so logical and easy. Sometimes if you’ve done a job the same way many, many times, other ways of achieving the same result do not enter your conscious thinking. I will be using Roy’s method from now on.
With Roy’s method you could also slightly taper the drawer bottom so that the width of the bottom at the drawer front is slightly narrower than the width at the back. This would always ensure that sliding it home
is easy. Square or tapered, the slips will match the fit. The beauty of this method is it also allows for a complete, easy dry run. Once you have shot the slips to the knife line, place them on either side of the drawer base and the drawer should fit over the top perfectly.
Before I glue the drawer slip to the drawer side I will use my scratch stock to place a small scratch bead into the slip. My scratch stock is the one I made in David Charlesworth’s workshop. I have three cutting profiles that I use. The cutting profile is cut into a small piece of old bandsaw blade. It protrudes out about 1mm. I clamped the scratch stock in my vice and ran the slip through repeatedly until I got a clean, uniform recess cut into the slip. Make sure you are always holding the slip firmly against the internal corner of the scratch stock so you get a consistent, parallel cut.
Once the glue has dried I could flush the underside of the slip to the underside of the drawer side and also cut the length of the slip flush with the back of the drawer and plane it flush. I intentionally left the slip 0.5mm proud of the underside of the drawer side so that I can flush it without altering the height of the drawer. When the drawer slips are flushed I will fit and secure the drawer base. I can then commence the final planing to fit. This is a matter of planing, checking, feeling and watching.
Take a shaving and then check the fit. Feel the fit and look for any shiny spots where the drawer side might be rubbing. This is an enjoyable time, when you are planing to the final fit!

Ensuring the slip is square to the drawer side

The scratch stock clamped in the vice and ready for use

Detail of the drawer slip with scratch bead

Gluing the drawer slip to the drawer side

Planing the slip flush to the drawer side

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