Hi, David I. and David S., and Colleagues - I took a look at the pedal plate on an 1889 Steinway, the oldest on the premises at the moment. (I figured if there were an oddball thread to be found it would be more likely the older the piano.) I found that screws anchoring the pivot rod were garden-variety No. 8 32-thread x 1/2 inch flat head machine screws. We have a box of these screws we keep on hand for the occasional replacement. To David S.: 30-thread would be very odd indeed. There is no current or recent (20th century) American, Canadian or British standard thread at 30 pitch. And that's why many thread guages skip that pitch. Metric threads don't quite approximate that either. I accidentally deleted your post on the topic, but I recall you mentioned measuring your screw diameter at something like 0.213 inch. That would be about right for a No. 12 screw, which should be 28 pitch in the fine-thread series. There would be no point in S&S using special threads for this part. Common hardware is available to do the job and it would be much more expensive to have custom-made screws and custom-made taps, etc. Sidebar: I have a very nice South Bend Precision Lathe that cuts 48 different thread pitches. Conspicuously absent from that list is 30-pitch. Another Sidebar: It is not desirable to set these screws "gorilla tight". Notice that the pivot rod makes contact with the screw very much off center from the axis of the screw. Using a screw this way would be considered abusive in some circles; it will cause the screw to break well below the tension needed to break a screw with concentric loading. However, tightening the screw moderately snug is more than adequate to hold the pivot rod. It's another example of an elegant mechanical design from S&S!! ~ Tom McNeil ~ Vermont Piano Restorations VermontPiano.com 346 Camp Street Barre, VT 05641 (802) 476-7072 I found one item in the archives on steinway pedal plate machine screws. Tapping is an option...but has anyone determined what the thread per inch is? Or do I have to go figure it out myself?...;-] I can get the screws if I buy the entire pedal system...;-[ David Ilvedson, RPTPacifica, CA 94044 **************Get fantasy football with free live scoring. Sign up for FanHouse Fantasy Football today. (http://www.fanhouse.com/fantasyaffair?ncid=aolspr00050000000020) -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/caut.php/attachments/20080722/201cc301/attachment.html
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