A vibration dampening system

[Manuka Jock]

Is this the answer we are all looking for ?
A bucket on a pole ???

[Woodwould]

How do you moisten vibration and why?

[Robomanic]

Some of his observations are great, but the maths behind his explanation is a bit patchy. The pole is acting like a spring and lever. The damped-spring-mass system (bucket of sand on a pole) IMHO would be the best. I would have to recommend against the pure spring-mass system (block of wood on a pole) because if he hits a resonant frequency I would not like to be standing close to it.

[Woodwould]

It's unlikely a constant frequency would be met when turning an out-of-balance chunk of wood as the periphery and therefore the mass would be systematically reduced, but the danger could present itself once the chunk had been turned down and closer to being balanced.

It could also get ugly if the lathe is left running and the chunk isn't reduced in diameter.

A method of disengaging the weight would be essential.

[Robomanic]

It is as you cross one of those points as it is being systematically reduced that bites you . Practical experience I'm afraid, when faced with the choice between stop switch or rough faster, I chose the latter and lived to tell the tail but not for the feint hearted.

Besides, the stop switch is only a temporary fix.

[NCArcher]

How do you moisten vibration and why?

Hmmm..If you fill the bucket with water, as the vibration increases the likelyhood of moisturisation increases dramatically.

[Manuka Jock]

An ingenious scheme for dealing with over dry wood eh

[Woodwould]

Hmmm..If you fill the bucket with water, as the vibration increases the likelyhood of moisturisation increases dramatically.

I suspect that's when he switched to using sand.


All in all, I think I'd prefer a solid steel bench bolted to the concrete floor. You really don't need 50lbs. of bucket and sand distracting you while you're approaching the centre of a bowl-saving cut.

[Texian]

A similar system came up on another forum. Seems like way more trouble than it could be worth. The purpose of the device, it was said on the other forum, was to enable one to spin out of balance pieces faster, and thus improve one's productivity. And if that fellow considers a 50 pound weight on a pole easily portable, he is younger and/or a lot stronger than I am now. Guess I'll do without this improvement.

[Manuka Jock]

His turning work is good tho ,
its just his engineering that a tad odd

[joe greiner]

Sounds like the concept of a "tuned mass damper," sometimes used in very tall buildings to reduce swaying under earthquake or wind load. These are usually suspended heavy pendulums with hinges to provide counter-vibration in lieu of flexure in the pole. Resonance could be particularly hazardous, when/if a very significant number of oscillations exceed the pole's fatigue-cycle life at low flexural stress.

>>>> Please DON'T do this. <<<<

Yes, I'm a Structural Engineer.

Joe

[Ed Reiss]

>>>> Please DON'T do this. <<<<

Yes, I'm a Structural Engineer.

Joe

Well, I'm not a structual engineer, brain surgeon, or even a rocket scientist...but even my dumb a** can see that this might not exactly be the best solution to vibration

Kinda' scary

[Manuka Jock]

If he wants to set up for turning outside in the summer , all he has to do is pour a block of concrete , with tie-down bolts cast in for the lathe .

Whats the point of all that up the pole crap .........

[NeilS]

This looks like a version of Glaser Tunable Vibration Absorber, details attached.

Seems to me that the same effect could be achieved by suspending the weights low down to the floor and then if something came adrift it wouldn't

Not that I'm suggesting the merit of such a system one way or the other.


Neil

[Texian]

Yeah, that was it. Perhaps more useful on non variable speed lathe to help counterbalance the vibration when roughing. That make sense.