Making a sliding door cabinet

Above: The completed cabinet in silky oak was stained to match the client’s existing furniture. 

Words and photos: Raf Nathan

This smallish cabinet was a recent commission designed to support a TV and house a collection of DVDs along with a DVD player. Silky oak was used throughout, however the client specifically wanted it stained to a light brown to fit in with existing decor.

It’s a solid wood cabinet so there are certain ways it can be made. Provided you make it correctly there won’t be any issues with timber movement as the grain of the sides and the top runs in the same direction. This means all the wood can move the same way. For this piece I glued up panels to make the top, sides and shelves.

A strong back

The DVD player that would be housed inside the cabinet would need good ventilation and so the carcase was designed without a back. Without bracing such as plywood on the back, the design may have been weak in regard to longevity. If the cabinet was banged hard or dropped it could rack and break the joints. In other words without a back it would not be triangulated.

To strengthen the piece I added what I call ‘plant-ons’ to both the front and the back. These also make the vertical element of the design of the piece much wider. There is also a piece of wood fixed under the top at the rear. These components are all well glued in place.

Saw and plane

First job was to select the wood, dock my chosen boards to rough length, and then machine them to final dimension.

Gluing up the panels from narrow boards I used a yellow glue and had clamps on both the top and bottom to even out the pressure and avoid cupping of the panel (photo 1).

Where possible I’ll make panels to the final desired width at glue-up. Having said that, if the panel was dry fitted to say 300mm wide it will probably be 300.5 or so after the glue is applied and has dried; it depends how accurate you want to be. Let the glue dry overnight.

In spite of how careful you might be lining up each board you’ll have some variation and a few high points. You can hand plane these flush and then I usually use a random orbital sander or a belt sander to flatten and smooth the panels. At this stage I would sand up to 120 grit. The next process is to dock the panels to final length. I have a small tablesaw with a sliding table for this.

Time to groove

With the panels sawn to final length the grooves for the sliding doors to slide in were milled in the base panel and top. A 6mm diameter spiral cutter in a small router was used for this (photo 2).

The grooves in the underneath of the top were made slightly deeper (photo 3). It is deeper so the door can be lifted right up into the groove and then swung forward for removal and insertion.

The placement of the grooves is obviously critical, and this is dictated by the thickness of the door and how much set back you want for the doors from the front edge.

The doors are 15mm thick and the groove is 6mm wide with the grooves 10mm apart so the doors can slide past each other with a millimetre to spare. In this case the grooves are 4mm deep on the lower shelf but 8mm deep in the top panel.

Making the joints

At this stage the check-outs for the front and back plant-ons are made in the base. I sawed most of the waste away for the notch, and then cleaned it up with a router plane. In photo 4 you can see how I clamped another piece of wood to the base to give more support for the router plane.

For all the jointing in this cabinet I used a biscuit joiner. In my opinion biscuits are perfectly adequate for this type of construction. The largest #20 size biscuits were used, and as you can see in the photos, I fitted as many biscuits as possible across the width of each board (photo 5).

For test fitting, before insertion you can place some biscuits on your bench and hammer them to compress the wood. This will let them slip loosely into the slots – later when glue is applied they will swell up and become tight (photo 6). I used new biscuits for the actual glue-up however.

With the panels cut to length, notches made and grooves routed, the panels can be given a sand again, at this stage I would go to 180 grit. Now is the time to double check all measurements and do a dry test fit. Make sure that the shelf is set back from the front enough for the doors to clear it. I know this from an unfortunate past experience.

Glue-time at last

The base, shelf and sides can now be glued together. In photos 7 and 8 you can see pieces of paper between the clamp cauls and the cabinet. This is to make sure that pressure is applied in the centre of the panel as well as the edges for a good strong glue joint.

Ensure all is square before the glue starts to set. I am using a large 360mm cabinetmakers square to check while also trying to get the base notch lined up neatly with the side edge (photo 9).

The next day the clamps can be removed and the cabinet prepped to receive the plant-ons. For this the notch and side panels need to meet flush. Use a chisel and square to get these flush and true. The plant-ons can be simply glued in place, providing of course they fit neatly in the notch. Keep the outer edges flush. I don’t sand this joint yet as I want to keep the pencil marks on the sides that I made when I cut the biscuits slots earlier.

The top can be fitted to the cabinet now. I sat it in position on the sides and marked where the biscuits needed to be placed. The biscuit slots were cut and I then sanded the underneath face of the top panel. Glue up is straightforward as shown in photo 10.

When clamps are removed the outside of the cabinet can be sanded up to 180 grit or higher and all edges chamfered.

Bookmatching the door panels

Now that the cabinet is assembled the exact size of the doors can be computed. The panels were prepared first as they need to be stained and polished prior to door assembly. Solid wood door panels will move across the width and if not pre-finished any shrinkage can result in a very noticeable line where unpolished wood is seen at the door frame edge.

The panels are a main feature so I decided to bookmatch them. A thick piece of 150mm wide silky oak was sawn in half, the board opened, machined and then glued together. I am not saying the bookmatch is beautiful but it does have an interesting pattern.

With the glue dry, the panel was thicknessed down to 6mm, sanded and stained to final colour with a tinted hardwax oil. I didn’t polish the lower edge or the endgrain near the corners. While the oil was drying I had time to prepare the door frame.

Making the doors

Key points for the doors are that the grain in the rails flows across the width so the one piece of wood was cut in half to achieve that. To keep a consistent width visible in the door frame the rails are 50mm wide, as 4mm will be lost in view on each side as it sits in the groove.

The stiles (the vertical pieces) are 45mm wide. I have the doors meeting at the middle with the stiles overlapping.

The door frame joints were made with dominos. If you don’t own or want to own a domino power tool, dowels would be acceptable for this joint and these require only a drill and jig to drill the holes. Just ensure the dowels themselves are a good fit in the holes.

A groove was made in the inside of door frames to accept the bookmatched panel using the same 6mm router cutter used for the grooves in the panels. The small router was again used for this, taking a pass over the wood from each side resulting in about a 6.3mm wide groove that leaves a bit of room for movement.

I did a dry fit of the door frames with their panels in place first. Everything was then prepped and the completed doors glued up flat and square (photo 11).

Over the years a panel may shrink in thickness and start to rattle in the frame, quite annoying. To prevent this, I applied glue to the lower edge and around 60mm up on each panel side when gluing it in place. Besides preventing any rattling, another benefit is that this strengthens the door as a unit. At least this is my personal approach.

After the glue is dry I spend time getting all the joint faces flush and level using a plane, straight edge and sander.

Doors that slide

The finished doors still need more work. They need to have the tongue formed that fits into the grooves, top and bottom. The tongue at the top of the doors is larger so it can be lifted up into the deeper groove in the underneath of the top. The same router with a fence is used for this operation (photo 12), although I do clean the rebate up afterwards with a shoulder plane.

Close the door

No matter how good your maths is the door will still need planing and fine fitting. My way is to have the bottom of the door and the inner edge of the rebate both making contact with the groove base and the top edge. As the wood wears away from being slid along over the years it should still slide and wear evenly. I find it takes quite a while to carefully remove, plane and re-fit the door to get a sweet fit.

The right side door stops at the inner edge of the plant-on, however the left door needs an extra gap-filling piece of wood glued to it to act as a stop. This is a length of 18 x 18mm silky oak glued on inside the plant-on.

There is also a rear brace glued under the top panel to stiffen it. The cabinet was made to support a TV so there will be some weight.

For door handles I used two oak Miller dowels. These are glued in place with the edge hand beveled.

Last and least

What can be the most important job takes the least words to describe. Much time was spent polishing and buffing the whole piece with hardwax oil (photo 13). The internal surfaces received two coats while the outer ones received four coats. Carnauba wax was last applied for a final sheen and silky smooth feel.

Raf Nathan @treeman777 is a furniture designer and maker who lives near Brisbane.