Cross Valves and Player Parts
By Craig Brougher
|Spencer Chase asked for someone to relate their experiences regarding Duo-Art cross valves. Ok, here goes.|
I hate them. They didn't work very well when they were new. I have even seen an early Aeolian attempt to prevent them from rotating. They flattened the stem at the top and let it guide through a fiber disk which was also slotted. Ridiculous! Obviously the fellow responsible for those silly things couldn't even figure, seeing as how the precision of the slot and flattened shaft would have to be as many times greater per degree second as the percentage difference between the diameter of the valve poppet and the diameter of the wire stem. Thanks, but if I'm not mistaken, Aeolian was a piano manufacturer, not an optical bombsight maker.
It is also rumored that the guy who designed the cross valves was just about ready to change his design to little scottie doggies, just before they fired him. It's just a rumor, so I can't verify that one. But he supposedly became a cookie cutter magnate.
I have built a tester to prove the ineffacacy of cross valves. It is a Duo-Art poppet captured between two valve plates open to air, with a feed tube in the valve well. One plate is a cross valve. the other side a new round valve plate. (Stainless, by the way). The idea is to measure air flow differences and noise. The cross valve struck out on both points. It is not efficient, and it is noisy. I took this tester to an Amica meeting in St. Louis Missouri years ago and demonstrated it there as well, so everybody wouldn't think I was crazy.
Some rebuilders used to say that they MUST be better valves because they were retained in all the top of the line players like the Steinways. Interesting too that those same rebuilders also retained the same inside valve seat leather (Chuckle). The truth is, and I have this from the horse's mouth, Aeolian had contracted for and built up thousands of Steinway stacks prematurely, anticipating a quick sale. That didn't happen, and they were stuck with all these stacks that would only fit Steinways. So while they were still developing for more modern designs on the Stecks and etc. They were frozen out from changing anything on the Steinways. Those stacks were already built.
Since we cannot get tough industrial leather tanned specifically for those kinds of valves, only garment leather which is soft and very compressible in contrast, then it is the kiss of death to rebuild the Steinways with new inside valve seat leather, and just as foolish not to replace that old leather with new. So what's the answer? Change the valve plates to new valve plates, top and bottom!
You can buy them directly from Robert Streicher, who is a super conscientious machinist and a great guy! His phone number is (717) 559-7403 and his address is PO Box 39, Pond Eddy, NY 12770.
Bob also makes all the stuff for Ampico A and B-- All the machined drawer parts, switch stuff, transmissions out of solid cast bronze and machined, the air switches, and even the fiber gear on the "B" drive motor, the fiber/brass motor brush holders, and if you have a need for some beautiful all new stainless steel control rods on an old Duo-Art, talk to Bob. [He will need a set to copy, though.] You want stuff like a beautifully machined pump crank rod and bearing system that will NEVER wear out? He's your man. That guy knows how to do it! And there is never a mistake. He really appreciates working for people who appreciate the care he takes, and his prices are very reasonable.
Ampico ball bleeds? He has tried 5 or 6 different designs already. Has studied them for about 12 years now, and just recently has come up with a ball bleed for Ampico B's that doesn't stick! I am amazed, since ball bearings are rolled with a thick dry lubricant that gets mixed with the metal and then tends to stick on brass seats once in awhile. I used to have to take his new ball bleeds and heat them to incandescence with a torch, then keep agitating them as they cooled back down again. That cured 99% of the problems. But these? They are plunk-ins. If you have an Ampico "B" and want it to play like it is supposed to, then you must have these ball bleeds--period.(I could go into another one of my _famous lectures_ about that, but for now, you are spared.)
(Message sent Fri 7 Jun 1996, 16:04:45 GMT, from time zone GMT.)