Longcase Clock

Kevin Ley takes the time to construct a longcase clock in zebrano and oak

Some years ago, I was commissioned by a client of long standing to make a set of furniture for his boardroom. The central element of the set was a large octagonal boardroom table and eight chairs. He later returned and asked me to make him a longcase clock in a similar style for the same room.

Design

The whole boardroom set had been inspired by a range of early 19th-century, High Gothic-style furniture seen by my client in Raby Castle, County Durham. This furniture was made of calamander – an Asian ebony with black heartwood and white sapwood – in a very ‘Old English’ style with Gothic influences – lots of gilt work, tracery and fussy design, popular at the turn of the 18th century.

Mine was a modern interpretation, capturing the chunky, stable, solid appearance and the dramatic contrast in the timber, but with clean lines and in solid wood, not veneer. My client’s brief for the clock was: less than 180mm high; in a traditional style to blend with the other furniture in the room; a moon dial; visible brass weights and pendulum; and a simple chime that could be silenced when needed.

We played around on the CAD program, to-ing and fro-ing drawings by email until this final design emerged. The base, body and plinth were one piece with a removable bonnet that dropped on and contained all the works. Glazed doors to the body and bonnet would give protection while allowing visibility of the clock’s moving pieces.

Timber

The main timber was zebrano to match the other furniture, but I was concerned about its dramatic figure and colour clashing with the clock face, and the weights and pendulum. The client had liked a mix of zebrano and oak in some kitchen units I made for his house, so we decided to back the face and body in oak- faced ply, and have fielded oak panel in the base front.

The timber had been in my timber store for some time and was ready for immediate use, so the components were cut out a little over-length and width, faced and thicknessed, and stacked in the workshop.

Movement

No, not movement of timber but the works of the clock! We selected a suitable German mechanical movement, moondial face and serpentine hands from the Yorkshire Clock Builders catalogue. The minimum clearances for the weights, chimes and pendulum were specified and were well within the existing design.

Construction

The sides and top and bottom rails of the base were cut to size, with stopped housings formed for the front fielded panel and the ply back. The solid oak front panel was cut to size and fielded on the router table using a vertical fielding cutter. The panel was scraped and sanded to a finish, and three coats of Aquacote applied. I like to finish loose panels before fitting so that any subsequent shrinkage does not show bare wood.

The bottom edges of the sides were shaped to the same shape as the plinth, and all the pieces were fitted together with biscuits, reinforced with pocket screws from the inside. The ply back panel was glued in, and the front fielded panel left loose. Once the joints had cured, the top edge was chamfered using a large bearing-guided chamfer cutter on my T11 router. The outside faces and edges were belt and orbital sanded then finished by hand.

The plinth pieces were cut to size and mitred on the radial arm saw. Biscuit slots were cut in all the mitres – biscuits help to prevent slip when gluing up as well as reinforcing the joint. The top edges were chamfered in the same way as the base top edges, the bottom edges shaped on the bandsaw, and finished with the drum sanding attachment on the radial arm saw.

The front was glued and screwed into position, and the sides glued at the front and reinforced with glue blocks. The sides were fixed at the back by a screw through an oversize hole covered by a washer, to allow for movement in the solid sides without compromising the front mitre joint. Lamello strap clamps were used to pull up the joints and hold everything in place while the glue was left to cure.

Bonnet

The bonnet was drawn full-size on hardboard to get accurate angles and sizes for the components. They were cut to size and biscuited together with the face board, cut out on the fretsaw, and glued into stopped housings. The seat and chime boards were made and fitted in position to the measurements supplied with the movement.

The back pitch of the bonnet roof had oak-faced ply glued into housings for strength, with a loose back fixed with small magnets, to cover the remainder of the opening. The bonnet was dropped onto the top of the body where spacer blocks on the tongues locate it. To ensure that the bonnet could not tip forward, especially when the door was open, a simple clip was fitted at the back.

The solid sides of the body had shoulders cut at the top and bottom to form tongues to attach the base and bonnet. Stopped housings were cut in the back edges of the sides, and the inside faces of the back top and bottom rails for the ply back. Tenons were cut on the top and bottom rails using the radial arm saw, and corresponding stub mortises cut in the sides on the bench mortiser. Glue was applied to the housings and mortises, and the body assembled. Once it had cured, it was fitted into the base, and the bottom tongues glued and screwed to the base sides.

Doors

Glazed doors were made to fit the body and bonnet fronts. The standard mortise and tenon joints were made on the Trend mortise and tenon jig. A rebate was cut in the back of the frames for the glass, bedded on a thin bead of clear silicone to prevent rattles, and held in with pinned retaining strips. The angled top of the bonnet door was cut from a wider solid piece after the tenons had been cut.

Flush fitting hinges were fitted using a self-centring hinge bit to drill the holes. I made magnetic catches from rare earth magnets glued into recesses. The doors were adjusted for fit and finished with three coats of Aquaseal before glazing.

Finishing

It was important to retain the crisp contrast of the markings in the zebrano so I used Aquaseal water-based acrylic floor varnish. This dries in an hour or so between coats and does not ‘yellow’ or darken the timber.

All the internal surfaces were sanded and sealed with three coats before assembly. This is easier to do prior to assembly and sealing the inside surfaces as well as the outside, ensures even moisture take-up and loss. The first coat, which tends to raise the grain, was sanded with 240-grit paper on a sanding block, and subsequent coats with 320 grit. The final coat was cut back with a Scotch Brite grey pad to give a satin finish.

Clock movement

The movement, with the dial attached and the chains tied in place over the cogs to stop them sliding off, was fitted to the seat board with the clamps provided, and centralised. Beware – the chains are easy to thread over the cogs with the movement out of the clock, but well nigh impossible with it fitted. I had applied some double-sided tape to the edges of the face and once I was happy with the positioning, I pressed it into place on the face backing board, before tightening the retaining nuts on the movement clamps.

The chime block was fixed to the chime board and the chime rods checked to be straight and clear of any obstruction, including each other. At this point, the clock was checked over and given a final buff with a soft cloth and moved into my study. When moving the clock, the bonnet with all the works inside is taken off and moved separately from the body, the chains being tied just below the cogs.

Adjustments

Using thin chocks and a spirit level, I made sure that the clock was standing level. The weights and pendulum were attached and the movement started. I listened carefully to the sound, hoping for a regular ‘tick-tock’. What I got was tick-TOCK, as though it was limping!

This meant that the clock was not ‘in beat’. To rectify this, I reached up to the top of the movement and took hold of the crutch that the pendulum attaches to and moved it from side to side. There is a point of resistance that should be equal on each side. By pushing the pendulum past this point on the ‘short’ side, I centralised the crutch and evened out the beat. It took a couple of goes but was worth it for accuracy and minimum wear.

The soft brass stems of the chime hammers were carefully bent until the hammers were 1.5mm away from the rods and striking centrally, 25mm below the rod top, giving a sweet, even note on each and the right spacing for the chime.

The central bushing on the minute hand is a friction fit and was subsequently turned to bring the minute hand to the correct position for the chime. The clock was left running in my study for several days, and I adjusted the knurled nut on the base of the pendulum upwards to run faster and downwards to run slower, until the clock was correct. These movements can be accurate to a few seconds a week.

Conclusion

This was a satisfying job – the clock looked good and was very accurate with a choice of a good, clear chime or silent running, selected by a lever on the front of the face. The removable bonnet made it easily transported and installed in the boardroom, and the client was pleased – job done!

PHOTOGRAPHS BY KEVIN LEY

Further reading