Anti-Vibration Technology

[tonyfoale]

Way back in time, working in 70's era mold shop, the lead and grease thing came in this way. One mentor [a cast bullet shooter] advised us lead shrinks slightly as it chills. The plug tightens it, dampening vibration well,

I thought about shrinkage and as a (probably unnecessary) precaution I heated the steel tube to red before pouring in the lead. This gave scope for the tube to contract onto the lead. I never attempted to measure if it did but there has never been any sign of a loose core and I must have made three 55+ years ago. I did think of trying to "tin" the inside but it worked without it and it did not seem an easy thing to do. In any case I am not so sure that a loose core would be detrimental.

I once tried something just for fun without intention of using it for real. I fixed a relatively small diameter rod to the back end of a boring bar with a mass that could be moved back and forth. This was an harmonic damper and it could be tuned to stop chatter. It was great but I considered it too much hassle to use as a workshop device. I wonder if the bar in the video works on a similar principle but inverted and put up inside instead of dangling out the back like mine.