Mobile Kitchen Cabinet – “A One-touch Drawer Opening System”

Modern hardware is too clever by half! This simple commission gave me the chance to try out Blum’s Tip-on push-to-open drawer system, and I have to say it’s wizard…

When I was asked to make this mobile kitchen unit, it presented the ideal opportunity to try out a new one-touch drawer opening system as the client didn’t want any visible knobs or handles.
The brief was to create a compact two-drawer unit to fit under a worktop and be easy to move out when necessary. It was to be as plain as possible, with painted mdf sides and drawer fronts. The drawer boxes were to be beech, and the unit was to have a solid oak top for contrast and durability.
There wasn’t much to design with this job, as the dimensions were completely dictated by the recess under the kitchen worktop where it was going to live. In order to create a seamless finish to all the edges, I decided to use a mitre-lock joint for the cabinet construction.

Starting the construction

I started by cutting the cabinet parts to size from 18mm thick mdf. I then machined a mitre-lock joint to all the edges with the exception of the top’s front edge. Using a mitre lock joint in this way meant that there was absolutely no room for error when cutting the panels to size; even if they were just a couple of millimetres out, they wouldn’t slot together without leaving unsightly gaps at the edges.
The orientation of the joint takes a bit of working out, photo 1, as the back needs to be able to slide into the joints made by the top, bottom and sides. This is easy to get wrong, and it’s worth marking out the various boards with the tongue orientation before they’re machined.

Building the carcass

The next job was to glue together the top, bottom and sides, photo 2, being very careful to ensure that the mitre lock tongues lined up perfectly at the corners, photo 3.
For the face frame I machined up three wider boards, photo 4, and ripped them to a final width of 36mm on the table saw, photo 5. I then mitred the corners and glued the three sections to the front edge of the cabinet, photo 6.

The back was fitted next, and this is where any mistakes in cutting the components to size would be most evident. Fortunately it went together well, photo 7, and while it was all cramped up I glued a panel of 18mm mdf into the bottom of the carcass so it was flush with the face frame. This would add a bit of mass to help with stability and stiffen the bottom of the cabinet.

Once this had dried I glued 18mm mdf panels to the inside faces of the two sides. They extended to about two-thirds of the height of the cabinet, again fitted flush with the face frame, to provide the fixing ground for the drawer runners.

Fixtures and fittings

I needed to fit heavy-duty castors to the unit, but they had to be small and attractive; after a search on the internet I found what I needed from www.manddonline.co.uk. They were designed to be screwed in place, but I wanted to use insert nuts and M6 screws, so I enlarged the mounting plate screw holes, photo 8, before temporarily fitting the castors to the base of the cabinet with the M6 screws, photo 9.

The final job for the cabinet itself was to trim the drawer fronts to size and sand everything to a fine finish before moving the cabinet and the drawer fronts to my spray-room. I gave them one coat of mdf primer, two coats of undercoat, and three coats of Farrow & Ball Estate Eggshell to complete the finish, photo 10.

The top was machined from one solid piece of oak. After sanding it, I applied several coats of Osmo Top Oil to all the surfaces, photo 11.

Making up the drawers

After machining up the beech for the drawer sides to 15mm thick and cutting the various parts to size, I set up my Leigh jig to cut the dovetails, photo 12. This jig quickly makes a neat strong joint with perfectly spaced and positioned pins and tails, photo 13, even if I do need to get the instructions out every time I use it! I assembled both drawers after cutting slots for their birch ply bases, inserted the base panels and checked that they were completely square while the glue set.

The right runners

I normally use Blum’s Tandembox drawer runners for all my cabinets. These fit under the drawer and are more or less invisible in use. There are various options.

• Single extension or full extension With full extension runners, the drawer projects completely out of the cabinet, allowing full access to the contents. With single extension runners, the drawer acts more like a traditional drawer and the rear part remains inside the cabinet when it’s opened.
• Standard duty or heavy duty Standard runners will take a 30kg load, while heavy duty ones can carry 50kg. It’s worth bearing in mind that the weight of the drawer itself may take up quite a bit of this loading.
• Tandem Plus or Tandem Plus Blumotion The latter is Blum’s soft-close mechanism.

Once it was fitted only to luxury kitchens, but has now become standard across all but the cheapest ranges of kitchen units. However, the Tip-on push-to-open system works only with Tandem Plus runners; it won’t work with a soft-close drawer.

All the various options come as two components – the runner itself and a locking mechanism which is attached to the front of the drawer. These usually need to be bought separately.

There are a couple of jigs available to aid fitting these runners, and I think Blum specify their use in order to comply with the terms of their warranty. I have one, photo 14, and it does speed up the fitting process. However, I don’t think they’re absolutely vital to get the runners to fit.

Housing the runners

The runners fit inside the rebate created when fitting the drawer bottom, and to facilitate this, the drawer bottom should be set 13mm in from the bottom edge. The back of the drawer box always needs to be notched to house the runner, but it depends on the drawer design whether or not the front also needs to be notched. For these drawers, with separate drawer fronts, I had to notch the front edge of the drawer box to house the locking mechanism, photo 15.

Fitting the components

The Tip-on system comes as two separate parts, photo 16. The main component, part no T55.1150S, consists of a pair of mechanisms, clips, rubber buffers and ends for the connecting rod; this costs £7.19. You need a connecting rod for drawers over 600mm wide. This is sold separately as part no T55.889W, costs a further £2.03. It’s not obvious on their website that you need this rod for wide drawers; in fact the rod is difficult to find unless you know the part number.

The main mechanism simply clips to the runner body, photo 17. The front depth adjustment device clips to the runner, photo 18, and the small rubber washer slides over the pin at the back of the runner, photo 19.

If the drawer is over 600mm wide, the connecting rod is cut 277mm shorter than the internal width of the cabinet and the two spring-loaded geared parts are pushed into the ends, photo 20. One other difference between fitting standard runners and the Tip-on system is that the back of the drawer box needs another notch to clear the Tip-on mechanism, photo 21.

Before fitting the drawer runners to the cabinet, I drilled a series of holes through the top panel so I could attach the decorative oak top later, photo 22. I didn’t want to risk getting the resultant dust in the runner mechanism by doing this later.

A helping hand

To fix the runners accurately for the top drawer, I cut a scrap piece of mdf into a template on which I could rest the runner while I screwed it in place, photo 23. The bottom runners were set flush with the bottom of the cabinet and were set back from the front edge by 4mm plus the thickness of the drawer front panel. Once the runners were fixed in place, I was able to fit the connecting rod between them, photo 24.

With the runners in place and the locking mechanism screwed to the front edge of the drawer box, the bottom drawer could then be fitted into the cabinet. To fix its front panel, I set spacers around the edge to make sure it was equidistant from the cabinet before screwing it to the drawer box, photo 25.

The top drawer is fitted in the same way. Then the drawer position can be fine-tuned by means of the various adjustments built into the runners, photo 26. All that remained was to screw the oak top into place from within the cabinet.

Summing up

This was the first time I’d used the Tip-on system, and I was very happy with the positive opening and closing of the drawers. The only slight problem I had was opening the top drawer. I had set the edge of the top panel 4mm back from the drawer-closed position, but my customer found that it was occasionally reluctant to open. I took the cabinet back to the workshop and rebated a further couple of millimetres from the front edge of the cabinet top (the painted mdf part, not the oak worktop) and this cured the problem. According to the drawer specification it needs from 2.5 to 5.5mm of travel to open the drawer, so it should have opened easily with a 4mm gap.

This would not be such a problem with lay-on drawer fronts as there’s an adjuster on the drawer runner. However, with a face-frame design the drawers have to sit flush with the frame and so can’t be adjusted in the same way. This is something I’ll be aware of when I use these runners again.