Longcase clock movements are robust and should last for many generations if serviced every ten years or so, but the wooden cases they occupy don’t always fare so well.
Now, when it was built your grandfather clock would have stood on a stone floor and all the joints and panels would have been rigid and straight. After 200 years the joints will have become loose, the timbers will have twisted and part of the plinth at the bottom might even have been sawn off to remove rotten wood caused by daily mopping of the flagstones it stood on for years.
Image 1 illustrates a case missing the top part of the break arch door and also the front and side cornice that supports the hood. Damage like this can happen during transportation but over the years simple humidity and temperature change causes wood to warp and glued joints to loosen as has happened here. By the way, the movement is fastened to the horizontal 'seat board' which sits on the vertical 'cheeks' of the case.
Longcase clocks therefore have a tendency to lean particularly if placed on a fitted carpet or an uneven floor. If yours leans backwards or forwards, quite apart from the risks of it toppling over because it's top heavy, there is a possibility that the pendulum will touch the backboard leaving telltale arc marks (see Image 2) or that the weights will scrape the trunk door as they fall leaving vertical tramlines on the inside of the door (Image 3). Both cause friction and will lead to the clock stopping.
If the case leans to the left or right, you might need to adjust the angle of the crutch (Image 4) relative to the pallets to set it in beat. And as it's the crutch that drives the pendulum, any forward or backward leaning could cause the pendulum block to come into contact with the front or back edge of the crutch loop; again the friction will cause the clock to stop.
But using a spirit level on the case is often pointless; where would you place it knowing that part is still straight or horizontal? And what if the cheeks that support the seat board are different heights or the cornice is not square to the sides of the trunk?
A degree of understanding and skill is needed when relocating these clocks or when refitted to the case you might find that the movement simply won’t run for more than a minute or two. For this reason, where I have serviced the movement I prefer to install it for the owner myself and although there is of course an additional cost element (£35/£40), it is modest and really only covers mileage and fuel.
Nevertheless, there are times when it’s not practicable for me to be present during installation so this six part guide will help you to focus in a systematic way on the points you need to bear in mind if you decide to do it yourself. What follows in the next five pages is mainly aimed at 8-day movements but much of it applies to 30 hour movements, too. It may not be so relevant to modern 3-train Westminster reproduction clocks though.
Generally, when it leaves me, the movement is set in beat in relation to the dial, not the movement. I use a spirit level to get the dial horizontal (Image 5) before I set the movement in beat. I do it this way because not all dials sit squarely on the movement that they're attached to, and as it’s the dial not the movement that you’ll be looking at for years to come, I anticipate you will raise one side of the seat board until the dial looks right (that is, the 12 is directly above the 6). In this respect, the angle of the movement behind it becomes irrelevant.
Even when all the joints are tight, these clocks also have a tendency to sway from side to side slightly (only 1 or 2mm so you probably won’t have noticed it) and that ‘sympathetic vibration’ causes many a clock to stop. In an 8 day clock, it is especially common around four days after winding. Fitted carpets and modern wood-effect floating floors laid on foam underlay make things even worse and the clock now needs a little more support. So even if you’re confident that your clock is stable, I strongly urge you to anchor it against the wall before you install the movement.
If you're not keen on DIY or don't have the tools, tell me and I will do this for £60 when I come to install the movement after servicing it but if you have the confidence and the tools, I'll now explain how it's done.