Pocket Watch Movement Holder
April 13, 2005
I took a small break from my clock project to make this pocket watch movement holder. You can click any of the pictures to see a larger version. For those of you uninvolved with the watch repair scene, the mechanical innards of a clock or watch are called the "movement". They often have a variety of delicate pieces, and so a movement holder is used to hold them safely while they're being worked on. The pictures above show top and bottom views of the completed movement holder, and one view of it holding an old Waltham pocket watch movement. I've been learning about repairing antique pocket watches, and ran across some pictures of this style of movement holder, where the arms adjust towards the center to fit the movement. I loved the symmetry and shapes in the design, so I decided to make one. I indulged my love of the design throughout the project. It could have been made far more simply and easily. The standoff slots could have been straight, the main plate could have been solid, and the swinging arms could have been straight. In fact, since the knurled locking nuts are under the standoffs, I could have removed the swinging arms altogether, and the need for the small bushings that they pivot around. But I liked the extra moving parts and the shapes they made. A truly great tool is not just functional, but also a joy to use. However silly they might be, I have no doubt that the frills in my movement holder will delight me endlessly.
Until I made this tool, I'd been using plain aluminum "ring" style movement holders. But I noticed that if I left one under a jar with a watch movement for a week or so, the holder would be covered with aluminum oxide when I returned. High grade watch movements use ruby or sapphire jewels to reduce friction because they are very hard. In fact, ruby is second only to diamond in hardness. They are brittle, but there's not a lot that can scratch them. But - rubies and sapphires are simply aluminum oxide crystals! So, I decided it would probably be wise to keep powdery aluminum oxide away from the jewels in my watch movements, and that provided a little additional motivation to make this tool.
Here are shots of the original layout of the main plate, and the rough cut plate. I milled the arc-shaped slots with a rotary table on my milling machine, and drilled or sawed the rest. It's made out of 3/16" brass plate, leftover from my clock project.
Here's a picture of one of the decorative washers I made for the heads of the foot screws. You can see them in the finished picture above, too. Like many of the other parts, they don't really serve any functional purpose. The head of the screws are plenty big and strong enough. But I decided that they would fit well with the aesthetic of the tool, and the theme of fanciful but not particularly functional parts. Plus, they look really good next to the blued heads of the screws.
These small brass bushings are about 1/4" in diameter, and .01" taller than the arms. I put them on a penny to show the scale. They go inside the pivot holes of the arms, and are held stationary by the same screw that holds the feet on. The foot screw and decorative washer tighten down on the bushing, and then the arm pivots loosely around it. This ensures that the foot screw can remain tight, holding the feet on securely, without interfering with the movement of the arms.
Here's a picture of the knurled locking nuts being made on the lathe. You can see here how they were made from a single brass rod. The deep notches indicate where they were cut apart. Making these reminded me that knurling is still something of a hit-or-miss process for me. I had to tinker with the knurling tool adjustments for a while before I was able to get the knurling wheels going properly, even though I cut the outer diameter to what I thought was the proper dimension.
Here's a picture of all the parts of the movement holder shown together. There are 22 of them - a lot more than I expected when I set out! I probably could have eliminated all but 7 parts, so I suppose my movement holder is 68% fanciful!