Originally Posted by
daruby
Replating and machining the piston after replating is not the hard part. The hard part is boring and honing the cylinder (with the large holes all around it) and ending up with a perfectly round and straight sided cylinder, and THEN getting a replated piston to fit with just the right tolerances. I had a long conversation with Paul Riggett on this topic when his techs were working with York in Markneukirchen from about 2007-2009 on trying to get their valve production under control. They never really did and it is not un-common for York valves to not be able to "spin" in the bore or have adverse wear. According to Paul, you have to know how to compensate for what happens with the boreing tools as it passes through the ports where there is no material on one side and yet is cutting material on the other side.
Some really interesting insight, Doug, thank you for sharing! I had a lesson with Steven Mead a few years ago (when I was still playing on a York Preference euph) and he mentioned how the valves on York instruments could sometimes have issues. I guess that's probably what he was referring to.
Willson 2900 TA-1 Euphonium - Denis Wick 4AM
Yamaha YSL-643 Trombone - Bob Reeves BrassArk 5G "Gladstone"
Yamaha YSL-8440 Trombone - Denis Wick 5BS
VMI 3301S BBb Tuba - Schilke Helleberg
Past:
York Preference 3067 Euphonium - Denis Wick 4AL
Benge 165F Trombone - Benge Marcellus
Wessex BR140 Baritone - Denis Wick 6BS
F.E. Olds Special Trombone (ca. 1941)