Autopiano Horror Story
By Jon Page
Aw schucks, it were nuttin'. I'd just like to clarify a few things:
The patent leather secondary facings were sticky, I replaced with PPS stock. The outside facings I made from leather and glued to fiber washers. There was no force-fit collar for the outside valve, just a sponge washer on each side (like that's going to hold).
The valve travel & pouch to valve clearance were excessive. The only hard part about these was removing the PVC-E sealer around the seats. (E-mail me privately for force-fit collar set jig description.)
The tricky part was the primary valves. (To start with, too much travel; and then finding patent leather glued to outside button, shiny side to glue.) Fixed that.
Problem: Massive ciphering. After many attempts to get a tight seal by changing order of re-assembly, still sluggish and ciphering. Finally, we looked at the boards themselves. The valve board was warped towards the back. The pouch board was warped towards the front. Both had a downwards bow and a twist. Jointing and planing the face surfaces increased vacuum, but still sluggish and ciphers.
The next observance was that the two center support blocks were forcing the middle of the primary deck upwards. Then, the two end vacuum supply/support blocks had hair-line cracks which expanded with screws in place. Once all the stress was removed from the unit and end blocks replaced, vacuum was restored.
Put it together, take it apart. Put it together, take it apart. Put it together, take it apart. Etc., etc.
The few remaining ciphers were traced to screws expanding hairline cracks between channels, which were not visible (without magnifying glass) and didn't leak on testing without screws installed. All channels had been given 2 coats of shellac, so these really eluded us. (Sluggishness disappeared once pouches were sealed).
Put it together, take it apart. Put it together, take it apart. Put it together, take it apart. Etc., etc.
All pouches had been previously installed with PVC-E (a real joy to remove), there was debris in the wells, prompting their replacement. This was when I noticed uneven depth, most of them were too deep; some not deep enough. Planing the surfaces and a Forstner bit got these uniform.
The sluggish tracking device needed a bleed on each of the upside-down pouches (cancel valves).
Replacing the menagerie of screws with uniformity makes for a nicer presentation.
Again I would like to plug the OverdriverPro (4 to 1 gear ratio) ratchet screwdriver. It makes quick work of "Put it together, take it apart." Available from McFeeley's #SK-2000 ($30.00) 800-443-7937
Jon Page
Harwich Port, Cape Cod, Mass. (jpage@capecod.net) |
(Message sent Sun 16 Feb 1997, 17:30:15 GMT, from time zone GMT-0500.) |
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