Head: Spoolbox + Transmission

So let’s see here… in terms of the “head” of the player action, I think I will actually just begin with the clean up of the spoolbox hardware and transmission, before moving on to the first significant challenge — the motor!

The hardware on the spoolbox should be intuitive to remove after some examination – it was for me. Most things are just screwed. Depending on how deep into it you want to get, you can remove every single screw and bolt for maximum cleaning possibility (or you may need to replate if there is significant corrosion – hopefully not!), but by so doing you also undo carefully calibrated set screws which join different rods or gears together. Given the choice it can be a real time-saver (at the time of reassembly and troubleshooting) to have these coupling screws remain intact. I am saving mine where possible. There is a nice little silver lining here, in that the number of calibrated linkage points are not as numerous as other actions; so even if you realize later that you’ve bungled the documentation on the teardown, at least you won’t have 30 calibration points to try and coordinate and harmonize.

Cleaning the hardware is necessary for function, but also cosmetically pleasing. My philosophy on the cleaning of original finishes (on metal or wood) is that leave everything intact where possible with historic patina, but do remove all surface dirt and grime, so it is at least “clean”. Some people really like to replate hardware and refinish piano no matter what, so that it looks “factory fresh”. I don’t feel this is necessary at all (unless original finishes are seriously compromised), but some people do. It’s simply a difference of opinion and aesthetics.

On my spoolbox there are two levers connected to slide valves which are on/off switches for the pedal and theme relays, from the tracker bar. In other words, if you want to “turn off” the input holes in the tracker bar for the pedal or theme function, you can do so here. The theme switch is probably the more useful of the two; if you have simple 88-note rolls with no theme coding, then there is no point in having the switch activated. The levers themselves are inside the spoolbox next to the next to the take up spool, but they are only part of the rotary valves which are actually mounted from the bass exterior side of the box. See here:

spoolbox: before

bits and pieces

clean, rebushed, ready for action
clean, rebushed, ready for action

I already discussed the tracker bar in the previous post (briefly), so let’s move along to the transmission. Transmissions work in conjunction with the converted rotational energy of the motor, to make roll turn smoothly, and then rewind at the conclusion of the roll. Additionally the transmission is connected with the tracking mechanism, which is another important device for smooth play of the roll. More on that later.

The transmission is a collection of metal shafts, sprockets, pinions, gears and chains, all mounted on a metal frame which is either stamped or cast. Metal which has been poorly cast has a tendency to oxidize and crumble over time (e.g. a century), so if you have the misfortune of an otherwise potentially nice action with a ruined transmission frame, you have little choice but to source a replacement.

Stamped actions are not without inconveniences. In my case, there is no way to disassemble the frame, as it was riveted together (a short-sighted cost savings). The following picture illustrates why this is a problem, when trying to remove the pinion shaft.

transmission points

There are seven points of business on this shaft. There is not enough clearance to slide away the pinion (4) or large sprocket (5) so that the Woodruff key (3) can be extracted. The solution suggested to me by John Tuttle was to spread, gently but firmly, the frame apart to gain a few extra mm to accomplish this. It was a bit tricky, but with some snap-ring pliers and medium wooden shims, I was able to make it work.

bits and pieces 2

Once that was done, the bottom shaft also gave me some trouble, because the set screw of the large gear had “buggered” (technical term) the shaft; overtightening caused a circular burr to form around the screw, and the burr makes the shaft very reticent to release the gear. Again some elbow grease is the answer, but it needs to be done the smart way – not carelessly! Support the frame with some wooden blocks and tap out the shank enough so it becomes free. You can then file a small groove in the damaged part of the shank, and replace the set screw (credit for this idea, also John Tuttle).
After the pieces have all been cleaned (with solvent), polished, rinsed (if necessary), and buffed, you are ready for reassembly! Yay!

transmission in progress
Getting there!

Once it is all back together, you can set it aside for now or put it back on the head shelf. Once the other head components are ready, it all must be put back together and calibrated.

Oh yes, don’t forget the lube! Traditionally this has been graphite-based lubricant, but this can turn into a sticky, gummy mess over time. Even 3-in-1 Oil attracts dust. I was recently recommended to try Marvel Mystery Oil, which is an automotive additive. It is supposed to lubricate well, and as its viscosity is on the low side it doesn’t get so gummy. We’ll see how it works!

transmission after
Waiting for a lube job