Vibration of the lathe

[Scott Brandstetter]

Odie, thanks for you last post. Great idea for fine tuning the lathe speed. I didn't want to hijack your thread so thought I'd start a new one. I have a Jet 14-42 and I'm removing the storage I originally had shown in the picture. BTW, thanks to those who pointed out just how unsafe it was for my tools to be where they were.

I have read many different views on how best to add weight to the lathe, reduce vibration, and thought I'd throw it out to the group for suggestions before I get started. Most what I read is as concrete bags to weigh it down. Any thoughts on how much weight I should add? Is one way better than another to support the bags. Thanks for the help and taking the time to respond

 

[Bill Boehme]

I think that sand is better than cement or ready mix concrete because you can always use the sand for other purposes in the future. Cement, concrete mix, and mortar will eventually get hard in the bag. There is also the possibility of the bag leaking which is a bigger problem if it isn't plain sand. A bag of sand weighs about 50 pounds and 2 to 4 bags should be sufficient. Start with two and add more only if needed. A bag of sand also is the least expensive way to add weight.

 

[robo hippy]

Like Bill said, the concrete will set up in the bag after a while. Just the humidity in the air will start the reaction. Slow but steady. I found 'tube sand' at my local big box store. I think they were about 50 pounds each. Comes in fiber plastic type tubes and are usually seen in the backs of pick up trucks during snow season. The loose material will be better at absorbing vibrations. I would load the lathe up with as much as you can put on it. Your efforts also depend on the frame of your lathe. The stamped metal ones aren't as sturdy as the cast metal or steel tube framed ones, so will never be as stable no matter how much weight you put on them. Having your lathe dead level is pretty big as well.

robo hippy

 

[john lucas]

I always worry about sand getting out of it's container and contaminating my tools . I went with bags of Pea Gravel. Seems to dampen the vibrations quite well and much easier to clean up in the case of a spill. I found some rip stop plastic bags that they use to contain sand for anchoring the tarps used in baseball fields. These have held up for 8 years.

 

[Michael Mendelsohn]

I went to the extreme of bolting the lathe to the concrete floor with expansion anchors. This is the equivalent of adding several tons of concrete to the weight of the lathe. I don't have problems with excessive vibration anymore.

 

[Odie]

I went to the extreme of bolting the lathe to the concrete floor with expansion anchors. This is the equivalent of adding several tons of concrete to the weight of the lathe. I don't have problems with excessive vibration anymore.

I bolt my lathe to the concrete floor, as well. It looks like Scott is mainly interested in weight. The vibrations always emanate at the turning itself, and then progress through the spindle, headstock, and then downward. Dealing with it at the source, or closer to the source, would always be the better way of dealing with it. Using a bowl steady works well for very minor balance conditions, as well as dealing with it from a resonating vibration......not for major out of balance. I once heard of a turner who used a timber beam wedged from the ceiling and compressing down on the headstock. That seems like it might deal with the problem a little closer to the source, but I've never attempted that, so don't know how well it would work.

Many turners use significantly out of balance wood, more than I ever use, so my input isn't from much experience with that. If anyone does use compression from above downwards, I'd sure be interested in what their analysis of this is.

Reducing, or eliminating vibrations that have already reached the lower portion of the lathe wouldn't help the actual cutting action of tool to wood very much. There may be some vibration that reaches upward through the banjo and tool rest, but not as significant as that vibration of the turning wood itself. I guess the lighter duty the lathe, and the less stable the platform, the more effect it may have on the cut. Except for the Shopsmith, my lathes have always been bolted down.......and I'm not sure how well the reaction would be if they had been free standing. When I did use the Shopsmith, I was such a newbie, that I'm not sure my perceptions would have counted, but I'm sure there was more vibrations with that platform, than anything I've turned on since then......

ooc

 

[Steve Worcester]

The potential with bolting down is the vibration. You go from vibration absorbed by the floor, lathe, etc, to ripping out of the floor. It seems to me to be binary, on/off, none/ catastrophic. Not that you will ever reach the tipping point, but the potential is, catastrophic.