----- Original Message ----- From: "Richard Brekne" <ricb at pianostemmer.no> ...plate ring resonant frequency going. That can be very objectionable indeed. Tho I wouldn't imagine it had much to do with the vertical hitch pin per sé. Ric, others, I'd like to answer your post again, now that I've had some time to think on it. I believe the plate ring is due entirely to the vertical hitch pin. I'm going to reveal a bit of the country (let's call it pioneer) experience from my childhood. Before we became so sophisticated that we began to purchase fish bait from a bait shop there existed a technique of gathering worms for fishing that I learned as a boy on our family farm. The process is this: Take a "stob" (country for "wooden stake, preferably from a tobacco stick, roughly 1 1/2" to 1 3/4" square by 18" to 24" long") and drive it in the ground, leaving oh, 10" to 12" sticking out. Rubbing a "grubbin' hoe" (we called it, may be mattocks?, a heavy hoe, approximately 6" wide by 8" or so long - an ax may also work) across the top of the "stob", having developed a bit of skill to the art, will create a "grunt" sound, somewhat like the sound of a bullfrog bellowing. After 5 minutes or so (depending on recent weather patterns) of grunting the stob, earthworms will begin to demonstrate their inability to cope with the wretched vibration and crawl to the surface. A well skilled grunter can produce vibrations that will enable harvesting of earthworms as far away as 30 to 50 feet from the stob. You can fish all day with what you can pick up. How many you catch is the subject for another forum. The longer the length of stob sticking out of the ground, the lower the grunt will be. Driven deeper, the grunt will be higher in pitch. Drive it too deep, and you can't make a sound. The length of wood will be too short to vibrate (at least react to this particular stimulus). Here, we have what is essentially a vertical hitch pin, transmitting vibrations. The length of springpin or rollpin protruding from the plate conducts, if not amplifies, the vibration from the hammer strike and string vibration to the plate, just like the stob does. It can't not. Unanonomously submitted, Jeff Tanner
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