Tuesday, February 12, 2013

Custom Crank Key (Part 1)

A fine clock deserves a fine key. If you are finicky with details (as I am), and you don't mind spending a bit of time, you too can easily make your own beautiful custom keys.

Tools Needed:

- Inexpensive Stock Key
- Jeweller's Lathe
- Files
- Brass Sheet (old movement plates)
- Soldering Sundries
- Jeweller's Saw & Hacksaw
- Sanding and Polishing Sundries

For this project, I'm simply starting with a cheap stock key (which cost around 2$).

Start by determining the length for the shaft of your key. If it needs to be short, you can use a standard key, and if it needs to be longer, you can use and extra long shaft key (shown above).

Start by cutting the end off the key. If you want to save and reuse the key top, you can unpin it (with a small punch). Smooth/grind the tip flat.

At this point, you can chuck it into your lathe, and let your imagination soar. There are several antique examples with fine lines that will always look good. You can choose to simply do a simple double line across a plain shaft, or you can do something completely custom and unique.

While the shaft is still in the lathe, get a good polish on it.

For the arm, you can also do anything that suits your fancy. Several Vienna cranks feature a loose S curve on the arm, others are flat. Some are tapered, and others are simply steel wire.

On mine, I chose to do a double circle, with an ovoid stem. I simply grabbed a piece of brass from an old movement plate (coincidentally an off-cut from the Laterndluhr movement plates), and cut the rough design.

Unfortunately I didn't take any photos of the process. Nothing too exciting to see. The blank was rough-cut with a hack saw, and then bulk of the excess was ground-off with a bench grinder. All the finishing touches on the profile edges, and the ovoid stem were all done with hand files.

To attach the stem to the arm, I simply used regular silver-bearing (low-temp) solder. The crank will never have so much force applied to it that it should warrant the use of real silver soldering (brazing), which I could have done - as I have the supplies. Normal solder will hold a few thousand pounds of pressure, and the weight on this clock is 4 Lbs without factoring the pulley (which halves the weight to 2 Lbs).

The soldering does make a huge mess, and will discolour the brass, so another round of polishing and cleaning were done.

At this point, I have 2 photos so far.

I haven't decided what to choose for the handle yet. I'm leaning towards ebony, walnut, mahogany, or cherry, but bone, holly, or boxwood would also be nice.

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