On adding weight to lathes

[John Whitley]

Since the prophecy has come to pass (🙄😂) and I have to wait until February for my new Nova Nebula(**), I figure I'll start a thread to collect experiences on adding weight to a lathe. I bring this up, since the Nebula adds a square crossbeam below the bed with a cap that can be removed to add weight. Nova suggests quartz/silica sand, for example.

The first question that springs to mind is: is this worth bothering with? My guesstimate back-of-napkin calculations don't suggest that sand adds a lot of weight. On the other hand, that weight is in a member which is solidly bolted to the frame. Likewise, a great many turners seem to get by just fine by not bothering.

A second question is: is more better? For example, if sand is good, is lead shot better? Related to that thought, on another thread, Odie expressed an interesting view:

[...] These are the times when the weight of the lathe itself, is important for tuning in the best vibration free rpm.

Note: It's not just a matter of adding sandbags, or weights suspended between the legs......but, weight incorporated into the body of the lathe itself is much more critically important for it's stabilizing effect.

If we assume this is true within some parameters, it suggests that the characteristics of any added mass is important. As examples/hypotheses, we could guess that mass coupling matters (e.g. mass relatively decoupled from lathe body, such that it doesn't absorb vibration or change the lathe's resonance much). Perhaps a kind of mass damping effect is in play, similar to how various acoustic treatment materials do/do not impact sound absorption/diffusion/blocking – see "limp mass vinyl" as one (acoustic) example application among many.

I tried to search the American Woodturner archives, hoping that some enterprising turner had Done Science To It on this topic, but my initial round of searches turned up zilch. If anyone knows of a resource, do please chime in.

Anyhow, I'm quite curious to see what various turner's thoughts and experiences are on the topic. Have at it!

(**) A footnote: I'm rather excited that I ended up selling my Galaxi to an enthusiastic new turner who was looking for their first lathe.

 

[Vincent Vogel]

Adding weight can't hurt, but when I had my Laguna 15/24 the best thing I did for stability was to increase the footprint. I made a lift lock and roll device and made the footprint 32" wide instead of the 18" from the factory, I also added 4" to the length of the footprint. The lathe sat on the factory feet when not lifted on the wheels to move it. It was very stable for a small lathe. It weighed about 400# with all the stuff I had hanging on it (toolbox and bed extension). I now have a Powermatic 3520 which I put Zambus leveling casters on it. I'm not satisfied with them, the rubber feet are too thick and too soft and allow the lathe to shake when there's an unbalanced piece of wood on it. It didn't do this with the factory feet. The Zambus casters are coming off when I decide where I want the lathe to sit and the factory feet are going back on. That's my 2 cents worth.

 

[John K Jordan]

Depends a a lot on what you like to turn. Turn large, unbalanced pieces? Extra mass can help.

But if you just occasionally turn unbalanced, there may be another option. A good friend turned large piece outboard on a relatively small lathe. His blanks were sometimes much out of balance. What solved things for him was using long pipe clamps to fasten the lathe to several joists of his little garage shop. No more vibration.

Personally, I don't use added mass. My primary lathe has enough mass I get no vibration on most the things I like to turn. Slight vibration can usually be eliminated by changing the speed a bit.

Your material dampening questions are good but I've read no hint of a study. Maybe that would be a good research project for you! The frequencies typical in turning may be a significant parameter when considering material properties.

JKJ

 

[Steve Saah]

I can’t provide any perspective on the Nebula crossbeam, but I’ve added what’s essentially a box constructed of 2x’s filled with sand between the legs on both a Jet and Galaxi. I can say with absolute certainty that in both cases it made a significant difference for me.

My gut tells me that sand or a similar material in the crossbeam on the Nebula would help dampen things a bit. Congrats on the new lathe!

 

[john lucas]

Mass helps. I added 350lbs of pea gravel to my 700lb powermatic. I have a friend who turns off center pieces. He changed the footpring of his lathe by adding 4" 1/2" thick angle iron to the legs. This made the footprint 6 feet intstead of 2 or what ever powermatic legs are. Made a huge difference. Much better than my pea gravel. on the inboard tailstock end he had the upper half of the angle iron cut off to prevent a trip hazard. I don't have enough room to do that but have been thinking about extending the footprint a little.

 

[Ron Solfest]

Do a search for a thread I started July 13, 2011 titled “Ballast”. I’d included a link but don’t know how to do that.

Quick summary is that I did some experiments with my PM3520 (600lb) adding 300lbs of weight. It improved the rpm level I could spin for unbalanced loads by ~10% (further down in the thread you’ll find additional experiments around where the ballast was placed).

My conclusion was, and remains, buy a high quality heavy lathe (PM, Oneway, Robust, etc) and don’t worry about adding ballast. I don’t know anything about the Nebula to suggest if it would benefit from ballast or not.

FWIW - the additional 300lb of ballast wasn’t worth the cost to move when I left MN for TN 8yrs ago and I have no thoughts of replacing it.

 

[JeffSmith]

Before adding weight, you might insure that all four feet are sharing the load as equally as possible. Level the lathe, check the bed for twist and get everything settled in before adding weight. I upgraded to a Robust over a decade ago and having the ability to adjust each leg Independently makes the process easier, while the included instructions on ‘settling’ the legs (not easy/possible on all lathes) also helps to reduce vibration. Make certain every nut and bolt is tight. In short, do everything to eliminate the potential for vibration before adding weight.

 

[Larry Copas]

When I started learning how to turn I added over a hundred pounds of sand weight to both ends of the lathe. I also added a toolbox between the legs which added more weight. Worked fine for normal bowl and spindle turning.

I began getting interested in turning extremely unbalanced pieces outboard and things like unbalanced root balls inboard. My added weights were no longer able to control vibrations. I than bolted the lathe to the concrete floor, problem mostly solved. My neighbor does occasionally ask if I felt that little earthquake tremor......I just smile.

My recommendation is bolt the lathe to the floor if possible and forget added weights. Actually bolting to the floor was a lot easier and cheaper than making a box, attaching to the headstock, and filling with sand. I would also do exactly as Jeff Smith recommended in post #7 and level the lathe before bolting it down.

 

[John Whitley]

A lot of great thoughts already, thanks everyone. A few replies below:

In short, do everything to eliminate the potential for vibration before adding weight.

Points well made. I'm far enough along that I'm aware of those techniques, what I'd call "the basics" of dialing in a lathe to a new location. (Aside: I feel like this is an important process which is obscure/arcane for new turners.) One recent “trick” I picked up on this front is to use a piece of paper as a kind of feeler gauge to help figure out which foot to adjust.

My recommendation is bolt the lathe to the floor if possible and forget added weights.

Funny enough, I’d been musing on exactly this. I’ll consider this treatment for the lathe once I’ve dialed in the baseline leveling and vibration tuning, if I feel like I need to go further.

 

[john lucas]

Do a search for a thread I started July 13, 2011 titled “Ballast”. I’d included a link but don’t know how to do that.

Quick summary is that I did some experiments with my PM3520 (600lb) adding 300lbs of weight. It improved the rpm level I could spin for unbalanced loads by ~10% (further down in the thread you’ll find additional experiments around where the ballast was placed).

My conclusion was, and remains, buy a high quality heavy lathe (PM, Oneway, Robust, etc) and don’t worry about adding ballast. I don’t know anything about the Nebula to suggest if it would benefit from ballast or not.

FWIW - the additional 300lb of ballast wasn’t worth the cost to move when I left MN for TN 8yrs ago and I have no thoughts of replacing it.

that's why I used pea gravel. it will be easy ti dispose of when i move. it's all in a box I made. early on I tried sand but somehow it always leaked out.

 

[Darryl Fective]

I added a shelf and stacked 11 bags of tube sand under my Problematic. The shelf was 1" thick plywood; stout material, but I put an eye bolt in the center with a piece of chain (in a V) bolted to the front and rear of the bed. With an extra 900 pounds added, it never danced again. (and if we ever had an ice storm, I had this backup stash of sand ready to load and spread)

A shot of it about to roll out the door to make way for an American Beauty.

 

[Dave Landers]

I added a box of sand under my PM 3520b when I got it. You can kinda see it in this pic.



I got rid of it when we moved, and I don't miss it.
Mass does help control vibration and "walking" if you're spinning something unbalanced. But you can also control these things, to a degree, using speed and better balancing before turning (chainsaw/bandsaw).
Among other things, I found that the box-o-sand made sweeping under the lathe fairly difficult. (Not a problem if you don't sweep.)
Whether extra mass is necessary depends on the lathe, and your style and habits.
So I'd suggest waiting. Use your new lathe and see how it reacts to you. If you need extra mass, then you'll know. And bolting the lathe to the floor, if possible, would get you a "world of mass" without inhibiting cleanup.

 

[robo hippy]

I have weight on all my bigger lathes, except for my Vicmark 240 which doesn't really have any where to put it. I used "tube sand" which are long bags of sand for going in the back of a pick up for extra weight in the winter snow conditions. I have wondered about filling the tube frame on my Robust lathes with sand, but doubt I ever will.

robo hippy

 

[Gerald Lawrence]

I used sand or was it dirt in a box on stand I made for a Delta midi. Yes it helped . Did the same for Jet 1442 but did not with the PM 3520B. The first two also had chest of drawers. I think that learning more about what causes vibration in addition to the weight spells why I do not need it now.

Balance a blank before you turn helps a Lon , then as has been said adjust the speed. Usually you can turn speed up till vibration begins and the turn up a little more. If that does not work turn the speed down. It is kind of finding a happy medium.

 

[Bryan Field]

I have a Nebula and so far have had no serious wobble issues without having added weight. I don't think that the additional few pounds of sand you can get into the cross member will make a significant difference. I think Darryl Fective has the right idea!

 

[Paul Abramshe]

I think the question concerning whether or not there is a better type of mass to add to a lathe is interesting. A monolithic mass balanced as close as possible to the source of vibration probably as close to under the ways as possible, unless you want to strap it to the head stock…would probably dampen the force exerted by an out of balance chunk of wood the best. This is true because it’s more difficult to overcome, since there’s less of a lever to act on the mass to move it. But if that mass is overcome by the force of the object being turned, it will become a falling hazard.

As far as material, since a concrete block is used to dampen buildings blowing in the wind—tuned mass dampers etc—, I think that is sufficient for a lathe. I think the primary issue would be insuring that the mass acted as a whole, and did not allow inertia to start moving pieces of the dampening object.

 

[John K Jordan]

I think the question concerning whether or not there is a better type of mass to add to a lathe is interesting.

How about the mass of the shop wall? I mentioned earlier how good friend turned large pieces outboard on a relatively small Delta lathe. His blanks were sometimes way out of balance. He stabilized the lathe by using long pipe clamps to fasten the lathe to several joists of his little garage shop. This was about 40 years ago.

Regardless of the mass added, perhaps consider the effect stresses from a heavy, unbalanced piece might have on the spindle bearings, etc.

 

[Paul Abramshe]

That is definitely another way to go. Anything that increases the footprint, or adds stabilizing structures works in the lathe’s advantage

All the same, the stress caused by the weight on the spindle bearings and on the headstock itself can cause premature degradation of the parts. Even stabilizing structures concentrate the force created by the imbalance on the mechanisms/structures used to hold the work piece. There could be a lot of additional wear. Basically anything not shored up is bearing the brunt of that force. The question is when will that additional stress cause failures.

 

[John Whitley]

I don't think that the additional few pounds of sand you can get into the cross member will make a significant difference.

Thanks Bryan. That was my thinking based on napkin math of the added weight from sand, and was in my thinking when I mentioned lead shot (which still may not be worth the bother!).

It seems like there's a pretty good consensus from reports:

1. First and foremost, do the basic setup work to eliminate sources of vibration: uneven lathe feet, bed twist, check headstock and tailstock alignment, etc. If that's all good and no vibration issues are cropping up – done!
2. When turning, fine-tune the lathe RPM to reduce vibration.
3. Weight does help and a LOT of weight can help more. Whether via ballast or even bolting the lathe to the shop or to The Very Earth.

When the new lathe arrives, I'm planning to have a go at some multi-axis spindle work along the lines of Barbara Dill's work. That'll be the acid test of my lathe setup chops...

 

[Delbert Goff]

I added 300 pounds of sand to my Nova Nebula and it definitely helps. It did not eliminate vibration when turning off balance pieces, but I can turn at higher speeds than before. In my opinion, this low-cost upgrade was definitely worth doing.

 

[Doug Freeman]

I think the question concerning whether or not there is a better type of mass to add to a lathe is interesting. A monolithic mass balanced as close as possible to the source of vibration probably as close to under the ways as possible, unless you want to strap it to the head stock…would probably dampen the force exerted by an out of balance chunk of wood the best. This is true because it’s more difficult to overcome, since there’s less of a lever to act on the mass to move it.

This is correct. If there was a way to bolt the head and tailstocks to the floor! 😬 Seriously, this is why bolting the lathe to a concrete floor works so well (as long as the lathe is a relatively stiff structure, which most of the middle and up cast or plate welded lathes are), and bolting to a wooden floor not quite as well. The stiffness of the overall structure plays an important role.

Bolting thick sheet lead, steel, cast iron, or other dense material to the lathe structure is very helpful. Adding stiff mass to the structure works better than sand for low frequency vibration, ie unbalanced work.

Sand can dampen higher frequency vibration (a “hum” during a cut at hi speed) differently, but only because the structure has a different resonance. Changing speed, the tool, the cutting angle or depth, tool rest, can all effect the resonant frequency in that situation.

For creating non structural ballast, small pieces of metal scrap will be more dense than sand, gravel, or concrete, and get more weight on the lathe.

Increasing the footprint helps by increasing the lever arm of the reaction force, but typically creates a trip hazard. Simply bolting the lathe down works best, and will typically be cheaper.

 

[Mark Jundanian]

Thanks Bryan. That was my thinking based on napkin math of the added weight from sand, and was in my thinking when I mentioned lead shot (which still may not be worth the bother!).

It seems like there's a pretty good consensus from reports:

1. First and foremost, do the basic setup work to eliminate sources of vibration: uneven lathe feet, bed twist, check headstock and tailstock alignment, etc. If that's all good and no vibration issues are cropping up – done!
2. When turning, fine-tune the lathe RPM to reduce vibration.
3. Weight does help and a LOT of weight can help more. Whether via ballast or even bolting the lathe to the shop or to The Very Earth.

When the new lathe arrives, I'm planning to have a go at some multi-axis spindle work along the lines of Barbara Dill's work. That'll be the acid test of my lathe setup chops...

Sounds like a good plan. Remember, too, you can also try to reduce the imbalance of a heavier piece before mounting.

A further thought I'd like to add. No matter how permanent that lathe location is, no one stays in a house forever (and we're not getting younger). So when thinking about how to add weight, give some thought to making it easy to remove.

 

[John Whitley]

Simply bolting the lathe down works best, and will typically be cheaper.

And if/when I go there, will scratch the itch to check out a great local tool library which has a rotohammer. Because I've learned the hard way that a hammer drill is not remotely in the same league as a rotohammer when boring into concrete. 😅

Remember, too, you can also try to reduce the imbalance of a heavier piece before mounting.

Good call; I should have made this one #4! I feel like there's a tradeoff curve here, of knowing when your lathe (and skill) can handle roughing a specific size piece easily on the lathe vs. when it's worth putting in more time in at the bandsaw.

No matter how permanent that lathe location is, no one stays in a house forever (and we're not getting younger). So when thinking about how to add weight, give some thought to making it easy to remove.

Another great point, and another one in favor of just bolting it (in my case) directly to the shop's slab floor. I'd embed some threaded inserts for suitable size all-thread rod. Later, I could later easily remove the all thread.

 

[John Grace]

Since the prophecy has come to pass (🙄😂) and I have to wait until February for my new Nova Nebula(**), I figure I'll start a thread to collect experiences on adding weight to a lathe. I bring this up, since the Nebula adds a square crossbeam below the bed with a cap that can be removed to add weight. Nova suggests quartz/silica sand, for example.

The first question that springs to mind is: is this worth bothering with? My guesstimate back-of-napkin calculations don't suggest that sand adds a lot of weight. On the other hand, that weight is in a member which is solidly bolted to the frame. Likewise, a great many turners seem to get by just fine by not bothering.

A second question is: is more better? For example, if sand is good, is lead shot better? Related to that thought, on another thread, Odie expressed an interesting view:


If we assume this is true within some parameters, it suggests that the characteristics of any added mass is important. As examples/hypotheses, we could guess that mass coupling matters (e.g. mass relatively decoupled from lathe body, such that it doesn't absorb vibration or change the lathe's resonance much). Perhaps a kind of mass damping effect is in play, similar to how various acoustic treatment materials do/do not impact sound absorption/diffusion/blocking – see "limp mass vinyl" as one (acoustic) example application among many.

I tried to search the American Woodturner archives, hoping that some enterprising turner had Done Science To It on this topic, but my initial round of searches turned up zilch. If anyone knows of a resource, do please chime in.

Anyhow, I'm quite curious to see what various turner's thoughts and experiences are on the topic. Have at it!

(**) A footnote: I'm rather excited that I ended up selling my Galaxi to an enthusiastic new turner who was looking for their first lathe.

I've owned the Nebula now for nearly a year and I'll be in the minority in that I do not prefer my machine weighted down. Keeping in mind this is a IMO situation but I use the 'wobble' of an unbalanced piece as a warning I may have the RPMs too high. Again...it's just a me thing but the concept has served me well for years. Additionally, depending on each of our respective machines...weighing them down may serve to just transfer the 'wobble' to another part of the machine risking metal fatigue/cracking etc. Individual results may vary...

 

[Doug Freeman]

Remember, too, you can also try to reduce the imbalance of a heavier piece before mounting.

Yep, this works well. Many times I do more trimming after the piece is mounted and I can let the heavy part drop to the bottom. The safety experts wont like this, but I use my 16” electric chain saw and a 4” chain wheel to do the trimming on the lathe (spindle locked).

 

[Kent Reisdorph]

Depends a a lot on what you like to turn. Turn large, unbalanced pieces? Extra mass can help.

But if you just occasionally turn unbalanced, there may be another option. A good friend turned large piece outboard on a relatively small lathe. His blanks were sometimes much out of balance. What solved things for him was using long pipe clamps to fasten the lathe to several joists of his little garage shop. No more vibration.

Personally, I don't use added mass. My primary lathe has enough mass I get no vibration on most the things I like to turn. Slight vibration can usually be eliminated by changing the speed a bit.

Your material dampening questions are good but I've read no hint of a study. Maybe that would be a good research project for you! The frequencies typical in turning may be a significant parameter when considering material properties.

JKJ

Pretty much the same here. I do turn some out of balance pieces, but I've never felt the need to add weight to my Rikon. It's something like 475 lbs, so not as heavy as a 3520. I figure if I need to add weight, I'm doing it wrong. That's not a criticism of you folks who turn large out of balance pieces that demand that extra weight.

 

[John K Jordan]

Pretty much the same here. I do turn some out of balance pieces, but I've never felt the need to add weight to my Rikon. It's something like 475 lbs, so not as heavy as a 3520. I figure if I need to add weight, I'm doing it wrong. That's not a criticism of you folks who turn large out of balance pieces that demand that extra weight.

I use the 3520b and on the rare occasion I've turned an out-of-round chunk I've not had a problem with vibration imbalance. One thing that can help is use the electric chainsaw in the shop and remove the high spots on the blank while it's mounted on the lathe.

JKJ