Having installed all the chests and pipes, and everything tested from the chest's push-rods, the keyframe and relay are the next on the list. This relay translates the keyless impulses (exhausing wind through holes in the music) to the powerful charge (pressure) impulses to operate the pallet valves in the main chest. The keyless keyframe contains no moving parts except the transport rollers and the grooved pressure roller. Its main component is the tracker-bar, of stainless steel. This is mounted onto a manifold block from where the tubing for the entire organ runs. Cleanliness is paramount here, and the junction between the steel and wood sections need careful treatment to ensure a good seal between tracker-bar and block, and not allowing leakage between adjacent holes - with only 1mm land between them.
Markings on the bottom of the tubing block indicate its authenticity.
The tubing run from the block beneath the tracker-bar was divided between odd and even holes, so I devised a layout for the relay so the odd holes fed one relay box and the even holes, the other. The relay is a double-decker unit situated just inside the back of the case, near the keyframe. The order of notes was hand-written on the cover plates on the relay, but their layout left the tubing runs from the keyframe in rather a mess, and I could see little merit in keeping it the same.
I took the covers off and inspected the innards, and discovered that apart from a little dust, it was in remarkable condition. Zephyr had been used for the action, with fixed bleed holes. Unlike normal leather, zephyr is virtually airtight, so hadn't been subjected to impregnation of dust. It was still as good as the day it was fitted back in 1978. I decided to leave it alone, and refitted the relay intact. Register pallets had been fitted beneath the bottom tier, so they were re-leathered and put back where they were. Being in a very accessible position meant the relay could be attended to whenever necessary later.
The main chest puff-board was re-leathered and re-fitted and the relay was tubed up to it. The organ had been fitted with two action relays, one of which was a primary relay with two outlets - one for the main puff-board and the other for the clarinet-mixture action chest. Eliminating both, I had allowed a cleaner, more spacious tubing layout. Future maintenance would be far simpler and more accessible.