Ballast

[Ron Solfest]

I have a PM3520 and have recently been turning wet oat blanks and needing to turn at slow speeds (~200rpm) until the blanks are rounded due to vibration. No surprise.

The purpose of this post is that I decided to try and add some ballast to allow faster speeds and thought I'd pass along my results for others consideration.

Forunately when I build the box under my lathe I built in 'hidden' storage underneath in case I someday wanted to add ballast. See picture below, the 2x6's across the bottom house two 3" high chambers, each 20" long by 14" wide.



I wanted to maximize the impact of the ballast. Rock or sand might have given me ~2x weight of water, but steel would be closer to ~8x so I found a local scrap steel yard to get scrap to fit in my box. Digging through their racks we decided that the easiest and cheapest would be to use 1"x10" and 5/4"x6/4" stock each about 19" long. It took two 1"x10" plates and four 5/4"x6/4" bars per each of the two chambers. Additionally I added a couple half inch plates on top that still fit in the 3" chamber. The net result of this is I fit 310lb of ballast. Lots more than I could have fit using sand, a bit less than if I filled it with gold bars. At $0.55/lb for scrap steel plus $30 torch cutting charges it still turned out to be $200 - might as well as been gold as far as my wife was concerned 😱

Now for the results. Using a 44lb oak half-log (~7" thick, ~17" across with corners cut off) I first ran it up to speed without the ballast, then did the same after adding 310lb ballast.

Running the lathe up to where it started moving a bit, then backing down as I do to turn I found the blank would run at ~200rpm without the ballast, and about 225rpm with the ballast added. I also used my handy seismograph app on my iPhone to objectively measure lathe movement. The app confirmed about 10% improvement at various measurements up to ~300rpm.

Conclusion - $200 for ~10% increase in rpm's when turning off-balance chunks is pretty steep for my blood. I was hoping for 25%-50% improvement, and even that would be marginal for me for the price. Knowing what I know now I wouldn't do it again, but I'm not removing the ballast either 🙂

Also knowing that 300lb addition to a ~600lb PM3520 only provides ~10% improvement, I wouldn't bother adding 100lb - 200lb that is realistically all you can really add with sand or other less dense ballasts.

My last take-away, after running the lathe up with the seismograph app, is that I might get slightly less conservative but still wouldn't run the blank I did the experiment with any faster than 250rpm before it was more balanced. Not a recommendation, just a comment...your mileage may vary etc...

My lathe is not bolted to the floor (sits on Woodriver casters - wheels retract so lath sits on rubber). Bottom line is that the PM3520 is already heavy enough that adding ballast doesn't do much. Hope this helps others.

Ron

 

[Odie]

Thanks for the insight. I'm surprised you weren't able to get more rpm's by adding the weight. I agree, hardly worth the effort, but also agree that as long as you've added the weight, you might as well keep it there.

As long as you do not intend to bolt your lathe to the floor, I've read somewhere of somebody else compressing their lathe to the floor, by using a brace mounted to the ceiling. Don't know if that's a worthwhile thought for you, but just thought I'd mention it. If your lathe itself is sitting on rubber, by eliminating the rubber and allowing it to stand on a solid surface may help. Is the floor a cement slab, or a constructed surface w/building materials? Obviously, a cement slab would be the better surface......but, I understand we all have to live with the limitations we are given.

Just wondering......once you got that block of wood to round, what rpm were you able to run it then?

ooc

 

[Bill Boehme]

While mass is a significant factor in controlling lathe vibration, it is not nearly as significant as how well the added mass absorbs and dissipates energy. Steel is far from the best material for accomplishing that. Basically, the steel is just modifying some of the natural structural frequencies. While the mass of the sand that could fit in the same space is considerably less than steel, it is far superior in providing dampening of the structural resonances.

 

[MichaelMouse]

Oscillation versus vibration. Large movement versus small. The whole shebang walking versus the rattle that loosens the tailstock quill lock. The Weeble approach seems popular, though in your case you might want to get that longer lever arm by ballasting/attaching at the floor. Won't do a lot for vibration, since that comes from flex in components or change in relationship between them, not from movement of the whole.

Agree that turning at 300 rpm is a bit frustrating. You have to control yourself, holding the tool firmly to the rest. I find swinging the tool rather than trying to punch it in is the best way to approach the problem. That, and repeating "don't push" over and over again until I have something round enough to reference the bevel. Only takes three-five minutes to get things, even as rough as what you show, to that point. Faster if you use your bandsaw.

http://i35.photobucket.com/albums/d160/GoodOnesGone/Trim-for-balance-1.jpg

By whittling top, bottom, and trimming the middle, I can round 8" deep on a 6 1/4" capacity Delta saw. All it takes is a spot on the bottom to rest on. Chainsaw and/or my scrub plane work for me. I'm limited to 16 over the bed of the 3000, and my wooden cabinet is splayed forward, extending aft as a cabinet far enough to allow rotating the head. Mass comes from the sheet goods in the stand, supplemented by my router bits, sheet metal working tools, biscuit joiner, etc. stored in toolboxes underneath. I've used the 180 speed a few times on some off-center type turnings, but it's rare indeed that I feel the need.

 

[Joe Greiner]

I don't have a PM3520 yet, and don't have room for one anyway. In the meantime, my HF34706 (with sheet-metal legs) has two buckets of railroad spikes on the lower shelf - bought at a yard sale for less than $10 IIRC, with no particular purpose in mind at the time. It behaves almost as well as a lathe with cast iron legs.

For even lower cost (free actually), tire shops run by responsible citizens have to dispose of used wheel weights, with costs for cartage. Re-using is generally a bad idea because the clips are weakened by re-bending. They're usually happy to give them away - might even include the buckets. Your only competition is cartridge reloaders.

 

[john lucas]

I went with pea gravel. Not as good as absorbing the vibration as sand but every time I've tried sand I get a leak sooner or later and have sand everywhere. I put 350lbs in some ripstop plastic bags like they use to make levee's. Stacked these on a 2x10 under the powermatic. That and leveling the lathe really reduced the vibration.
My good friend Joe Looper who is gone now found a place in town that makes truck oil filters. They punch steel out to make part of the filters so they had barrels and barrels of 1/4" by 16 gauge steel punches. He filled his lathe stand with these. man did that work well.

 

[Charlie Knighton]

Ron,

can you mount a saddle behind you motor, add 3 or 4 bags of sand, measure before and after sand??? i would be interested if there is any differance when you get weight above spindle height

 

[robo hippy]

First thing I noticed was the wheels on your lathe. If they retract, and then sit on rubber, the rubber can add to the wobble problem, unless it is very hard stuff, and if it is that hard, then wood would be better. With my Robust, I just leave it as is, though I have added some heavy wood blanks (lignum and cocobolo) for weight. I did not notice a significant improvement. Some do bolt their lathes to the floor, and I don't think I would do that one. Too rigid, and there does need to be some wobble room so all the stress doesn't go into the lathe bed, headstock, tailstock, and legs.

Patience grasshopper!

robo hippy

 

[MichaelMouse]

Some do bolt their lathes to the floor, and I don't think I would do that one. Too rigid, and there does need to be some wobble room so all the stress doesn't go into the lathe bed, headstock, tailstock, and legs.

At least you didn't say bearings, which is what people say most often. Nonetheless, any gaps in the chain of parts you mention would be subject to the same force regardless. It matters not how the legs are held to the floor, whether by their own mass/geometry, bolts or bags.

Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales et in partes contrarias dirigi. (WIKI)

You want to do the best by your machine and yourself, read the second law in the language you prefer, and lower the velocity or mass of the mover. Why do people want to rotate at the ragged edge of disaster? Because you can infinitely vary rpm doesn't mean you have to crank up.

 

[john lucas]

I have a friend who used to turn out of balance hollow forms with a hole in the side. He had to turn these as fast as possible to get a clean finish inside because you couldn't sand them. He put some heavy angle iron under each leg that was 6 feet long. This not only added weight but really cut down on vibration and the lathe wanting to walk.

 

[Mark Mandell]

Another Way Cheap Too

Ron,

I've posted the information here before, but here goes again. You could add twice what you did and you still wouldn't get the result you seek because the physics are wrong. Go to John Williams' site at

http://www.woodisfun.ca/index.php?option=com_content&view=category&layout=blog&id=60&Itemid=161

where you will find both the novel solution and the why. I have passed this along to any number of turners, and I always had the same response: "It ain't pretty but it sure does work."

I've used John's rig on a 1236 (attached to the ways to the left of the headstock) and on a 3520 with the HS moved a bit. 36" section of 4" steel pipe, some 1/4" plate, and some weight is about all you need.

Save your nice "underbox" for storage, but see if the junkman will buy back or exchange some of that steel.

 

[Odie]

Ron,

I've posted the information here before, but here goes again. You could add twice what you did and you still wouldn't get the result you seek because the physics are wrong. Go to John Williams' site at

http://www.woodisfun.ca/index.php?option=com_content&view=category&layout=blog&id=60&Itemid=161

where you will find both the novel solution and the why. I have passed this along to any number of turners, and I always had the same response: "It ain't pretty but it sure does work."

I've used John's rig on a 1236 (attached to the ways to the left of the headstock) and on a 3520 with the HS moved a bit. 36" section of 4" steel pipe, some 1/4" plate, and some weight is about all you need.

Save your nice "underbox" for storage, but see if the junkman will buy back or exchange some of that steel.

Now, there is a novel approach to the problem! Never heard of that one before, and it looks like it may have some merit to it. It never ceases to amaze me of the ingenuity shown by other turners!

Thanks for posting that, Mark.........

I suppose this all boils down to a question of how much out of balance one intends to work with. For myself, bolting down to the concrete slab works very well......but, I don't deal with turnings that are badly out of balance from the start. All of my turnings are relatively in, or close to balance when I put them on the lathe. Any out of balance conditions I do have are only until the piece is "trued", or brought to round. I always feel the lathe when I bring up to speed, and when the vibration is noticeable, I back off slightly to where is doesn't. When the piece is trued, I can then bring up to higher speeds.

ooc

 

[Bill Boehme]

.... Go to John Williams' site at

http://www.woodisfun.ca/index.php?option=com_content&view=category&layout=blog&id=60&Itemid=161

When I clicked on the link, I got the following warning message so I decided not to go there.



This is only the second time that I have ever received that warning which is generally reserved for especially dangerous "attack" sites. Perhaps it is possible that the site has been hacked. Hopefully, the owner will find out that there is something wrong and check out his site for malware.

 

[Bill Boehme]

.... i would be interested if there is any differance when you get weight above spindle height

placing mass up above the spindle height (or anywhere above the existing center of mass) decreases stability margins. It is akin to the issues of balancing a pendulum with the pivot at the top versus having the pivot at the bottom. The first condition is statically stable while the second is unstable.

 

[Joe Greiner]

It opens fine for me, Bill. Might be your security settings instead.

In any event, we plowed this ground a couple weeks ago (Counterbalance Jig): http://www.aawforum.org/vbforum/showthread.php?t=8782&page=3

 

[john lucas]

It opened for me. Bill are you saying we should hang the weight below the lathe instead of above as in the photo. oops forgot you couldn't open it. Here it is. The reason I'm wondering is I have an outboard bed attached on the headboard side of my lathe. It's kind of out the way in that position because the 3520 motor sits over it. When I need it of course I can just slide the motor out. What I'm thinking is I could mount the weight,either above or below that extension. it would be out of my way and hopefully provide some stabilization.
I think I mentioned it somewhere before but I'm starting to do one piece handled mirrors. They need to be turned at high speed since your only contacting once per revolution. Even though they are very light they start setting up some vibration when you crank the speed up. I'm wondering if the bucket idea, Which looks like a modified version of the Jerry Glaser extended arm, will actually work.

 

[Mark Mandell]

For myself, bolting down to the concrete slab works very well......

Not the best option, Odie. Bolting the machine down will tend to concentrate the operating vibrations in the spindle bearings and cause abnormal wear. This is why industrial machines are [almost never] bolted to a factory floor, but rather are mounted on isolators.

As I said, John's "system" works very well for the usual out-of-balance chunk of wood. I would not, however, use it as a substitute for the kind of counterbalance plates that that crazy Kiwi, Terry Scott, uses.😀

 

[MichaelMouse]

I think I mentioned it somewhere before but I'm starting to do one piece handled mirrors. They need to be turned at high speed since your only contacting once per revolution.

And they contact more than once per revolution if you speed up? Slow your tooling feed and the shaving is the same thickness. If you are too impatient, consider embedding the handle in a large mdf disk mounted to a second which is on a faceplate. That will give you two things - balance, and a pattern. Second one cuts down to the level of the first. Or just glue it without lateral support if you have confidence in that method. It'll still make contact only once per revolution, though. I find it helps with impatience if I take a broad shaving versus a narrow when things are slow.

Keeping the center of gravity low is a good thing. In your case, it might be that sliding to one end lightens the load on the other making it possible for it to move more. Weight the opposite end equal or larger than the load on the working end, but don't top load. It'll take more to get the top moving if you weight it, but it will also take more to stop it if it does....

 

[Thomas Stegall]

I feel your pain, I sometimes turn large logs (I have a Nichols lathe we call "The Green Monster" that turns up to 32" dia and 78"long) and hate having to start so slow but, when things are off balance vibration that prevents faster speeds can be a healthy limitation to prevent injury.

I think MM may have a good point that your phone probably does not discern small vibrations from larger movements. I would think that large movement would require weight, small vibrations are probably to some degree more about the type of material. Although not as dense, I would guess sand would deaden vibrations of a certain frequency range better than sollid chunks of metal?

 

[john lucas]

MM You can't move the tool smooth enough when moving at slow speeds. Even with the handle against my body. the faster the handle moves the easier it is to control when trying to get a clean form.
I do the speed of cut demo sometimes when doing demos. I'll slow the lathe down and painstakingly move the gouge to show that it's not speed of the lathe but the speed of the cut. however it's very hard to get a really smooth arc when your body is moving that slow.
A good example of this is to try and draw a line on a chalk board that is 2 feet long. For the first line draw it at a normal speed. It will take you about 1 to 3 seconds and the line is relatively smooth. If you try the same thing but take 1 minute to draw the line you will see that it is very difficult to get a nice smooth arc or line. It will have little undulations.

 

[MichaelMouse]

Swing the gouge. That way you're not going 1:1 but maybe 12:1. Same as with the sweeping curve in your analogy, you use the big muscles. Allows you to make a six-inch movement (big arc) into a half-inch traverse.

Alternative two is to lock all the small muscles and sweep by shifting weight or rotating at the hips.

Give 'er a go. It's been working for ages.

Just wet enough to destroy all possibility of outdoor work today. Bummer.

 

[john lucas]

I do use the big muscle groups and move my body. I also turn from the end of the handle to give me more control. I keep the handle on my hip. I know we've had that discussion before but i'm short and it works out very well for me. however when you have to move the tip of the gouge almost 10" you can't really swing the handle. Your whole body has to move. I've been a gymnast, a dancer and rock climber and I have pretty good control of my body movements. When your turning mostly air you have to be extremely light with the tool. Any movement however small shows up a mark on the turning. I just find I can produce a smoother arc when I move my body at a little faster rate. I'll certainly be trying more tips because I'm going to turn more of these. Next time I'm doing them I'll try slow and fast just to see.

 

[Odie]

MM You can't move the tool smooth enough when moving at slow speeds. Even with the handle against my body. the faster the handle moves the easier it is to control when trying to get a clean form.
I do the speed of cut demo sometimes when doing demos. I'll slow the lathe down and painstakingly move the gouge to show that it's not speed of the lathe but the speed of the cut. however it's very hard to get a really smooth arc when your body is moving that slow.
A good example of this is to try and draw a line on a chalk board that is 2 feet long. For the first line draw it at a normal speed. It will take you about 1 to 3 seconds and the line is relatively smooth. If you try the same thing but take 1 minute to draw the line you will see that it is very difficult to get a nice smooth arc or line. It will have little undulations.

My findings are the same as John Lucas on this. It's difficult to have smooth tool control through an arc at very slow speeds.

This thread points out that slow speed is sometimes necessary to bring your turning to round, and balanced.......but, for final shaping, faster is better.

ooc

 

[Odie]

Not the best option, Odie. Bolting the machine down will tend to concentrate the operating vibrations in the spindle bearings and cause abnormal wear. This is why industrial machines are [almost never] bolted to a factory floor, but rather are mounted on isolators.

As I said, John's "system" works very well for the usual out-of-balance chunk of wood. I would not, however, use it as a substitute for the kind of counterbalance plates that that crazy Kiwi, Terry Scott, uses.😀

Mark......

There is one big difference here.

Heavy industrial machines do not have cutting tools hand held by the operator. Yes, you are correct that many industrial tools do have some way to "give and take" with out of balance conditions. Where I work, we have six CNC screw machines that are basically computer controlled automatic metal lathes fed from bar stock through a collet from the back side of the spindle. These are mounted with flexible footings. The point about the screw machines is that the tooling moves with the machine, so flexible footing doesn't create a tolerance issue. For hand held cutting tools, a wood lathe that is rigid will enable a smoother cut, over a lathe that is allowed to oscillate independently from the cutting tool.

My Woodfast lathe has been in use now for 19 years, and the bearings are still solid, no play. As I said, I deal with only minimal out of balance conditions with the turning I do.....so somebody else who routinely deals with this issue, might have different experience than I do. Bottom line, though......I want that rigid mount, because it will enable a smoother cut from a hand held cutting tool. I realize the bearings are taking on extra stress because of the rigid mount, but for me, the bearing life is a lesser consideration than the quality of the cut. Regardless, the bearings in my Woodfast lathe have held up well. When they do develop any play, I'll replace them.......no problem to do that. If they wore out today, and I could expect about a 20 year bearing life span.....I may not live long enough to worry about replacing them a second time......but, if I do live to be 82, and still turning (I hope so!), I'll just replace them again! 😀

I have attempted to make a specific point that my turning work isn't the same as everyone else's, but certainly it's the same as some other turners. If someone else does a quantity of considerably out of balanced work, then the circumstances will be different, and may require an alternate course of action.....

ooc

 

[Ron Solfest]

Thanks for the replies. I did a little more experimentation yesterday to gather some further data, and they turned the 44lb log I was using along with another one...much more fun making shavings than moving 300lb of steel around in the humidity we had.

First a comment on the mass and damping feedback (thanks for the Lex III comment MM, brought back fond memories of my high school physics teacher). The problem I'm trying to deal with is not high frequency vibrations, nor harmonics, etc but strictly oscillations directly related to the frequency of the out of round mass I'm spinning. The PM3520 cast iron already does a good job damping any harmonics etc, I just need to couple more mass to get less motion from the rotating mass. Optimal would be dynamically counterbalanced mass like with tire weights, but adding stationary mass just makes it tougher for the spinning log to create lathe motion. Species of the mass (sand, steel, etc) doesn't matter, just quantity of the mass. Steel just allows me to get a higher mass with less space.

Moving steel plates yesterday wasn't a lot of fun so I didn't do all of the apples to apples comparisons I'd contemplated. What I did was put 200lb (four 1"x10"x19" steel plates) on the ways, and on top of the headstock to see the impact it had on reducing the lathe motion. Again I used the accelerometer in the iPhone to measure this motion more objectively than with just my eyes.

I expected that mass on the ways would be more efficient than mass on the bottom of the lathe, it probably is but not much. 200lb on the ways wasn't as good as 300lb underneath, and appeared to be roughly half as good. Precision not really good enough to distinguish efficiency.

Regarding the mass set directly on the headstock I was even more surprised. 200lb on the headstock was a little better than 300lb low for initial motion but motion at 300rpm was as large as if there were no additional ballast. This goes to the cantilevered weight question others have discussed, I think Bill Boehme has it right. While initial stability may be slightly better, secondary stability suffers greatly (opposite of well design canoes...but that's another story).

Data for those engineers amongst us:

Subjective . . . . . . . . . . Original . . . 300lb low . . . 200lb ways/h'stock
- Oscillations began . . . . 220rpm . . . 250rpm . . . . 230rpm/260rpm
- Comfortable to turn . . . 200 . . . . . . 225 . . . . . . 220/230
Objective
- Motion below 1 . . . . . . 220 . . . . . . 250 . . . . . . 230/230
- Motion regular 1 . . . . . 250 . . . . . . 280 . . . . . . 260/280
- Sine motion at 1 . . . . . 300 . . . . . . 320 . . . . . . 305/300
Objective data uses 1 tick on the seismograph app, resolution not great but good enough to understand what's going on.

When all is said and done, I'll leave my 300lb weight at the bottom of the lathe. What would I recommend to a friend? Buy a heavy lathe (any of the 'premier' lathes, of which I consider the PM3520 the cheapest) and don't bother with ballast; the slight improvement you get isn't worth it.

Conversely I do believe that lathes that have sheet metal stands and weigh less than 600lb will benefit from ballast. In which case I'd recommend getting the most weight that's cheapest and easy to deal with.

By the way, after messing around with moving weights and running the lathe up well beyond where I would have previously been comfortable turning, my comfort level changed a little and I roughed that log out at 280rpm. There was some motion but manageable, and things went lots faster than starting out at 200. Once round, the PM3520 easily spins it as fast as I want to go (6000-9000/diameter) without any significant motion.

 

[Harry Robinette]

Ron
Sew the legs of a pair of jeans close fill with sand,gravel or small steel pellets
throw one leg over the headstock and one in the front. You'll get allot less circular movement and vibration. You need to stop the movement were it starts which is at the spindle.
Just my $.02

 

[Charlie Knighton]

thanks Ron, very interesting

 

[Odie]

First a comment on the mass and damping feedback (thanks for the Lex III comment MM, brought back fond memories of my high school physics teacher). The problem I'm trying to deal with is not high frequency vibrations, nor harmonics, etc but strictly oscillations directly related to the frequency of the out of round mass I'm spinning. The PM3520 cast iron already does a good job damping any harmonics etc, I just need to couple more mass to get less motion from the rotating mass. Optimal would be dynamically counterbalanced mass like with tire weights, but adding stationary mass just makes it tougher for the spinning log to create lathe motion. Species of the mass (sand, steel, etc) doesn't matter, just quantity of the mass. Steel just allows me to get a higher mass with less space.

Thanks, Ron.......

I think you've hit on an important point here about different types of vibrations.....frequency, harmonics (resonate?), and of course, the off balance centrifugal forces......which looks like what is your main concern.

It does seem like adding weight alone, and bolting to the floor, are pretty much going to counter these off balance centrifugal forces in the same manner......tending to help make the lathe immovable to these forces.

Tell me where and if I err, but to my thinking, sand and pea gravel, that sort of thing, will tend to absorb a shock wave (high frequency vibrations?) more effectively, but have little advantage over the kind of movement the off balance centrifugal forces deliver, other than whatever weight they posess......?

ooc

 

[MichaelMouse]

If you have the time - it seems you have an investigative nature - try shifting the weight to the rear legs rather than centering it on the shelf. As there will be a tendency to lift the rear legs as the overweight portion comes over the top, you'll have the inertia LEX 1 where it can exert the best influence.

OD and others of the loose sand or shot persuasion - remember that individual particles may move as momentum is transferred, imitating an inelastic collision, but the container will still tend to respond as a totality for anything above vibration level.

 

[Odie]

OD and others of the loose sand or shot persuasion - remember that individual particles may move as momentum is transferred, imitating an inelastic collision, but the container will still tend to respond as a totality for anything above vibration level.

You have misinterpreted MM..........

Actually, my thinking is very similar to yours on this, and your description of it is very good, well put. To me, the loose shot, or sand, will absorb the same kind of shock wave as a "dead blow" hammer......something that is entirely different than the off center centrifugal forces that Ron is attempting to eliminate, or reduce. I'm to the thinking that dead weight, or bolting down, will handle this kind of vibration much in the same manner as the shot/sand is capable of under these circumstances. The shot/sand/pea gravel will act on the vibrations purely from the weight they possess, and not from any additional ability to dampen oscillations from an out of balance condition.

ooc

 

[Bill Luce]

I love the attempt in this thread to control some of the variables with ballast to get at what really helps rather than relying on convential wisdom. Like the conventional wisdom that the 1 inch toolpost is the limiting factor with most banjos.....

I have never tried ballast, but early on found when I put a short extention on both ends of my 2436 it helped it's stability with off balance pieces more than I expected it to help based soley on the extra weight.

Also in my experience how even a contact on the ground a lathe has is critical and the biggest factor.

For example in St Paul at first the AB at the R booth was a real hopper and posed a challenge. But after Brent loosened all the bolts between the legs and lathe body to allow the lathe to accurately "settle" and then retightened, the lathe was impressively stable for such a light lathe.

Probably in part due to the splayed legs, but impressively stable none the less for only weighing like 650 lbs or so. Would be interesting to have all the top lathes in the same room and set up optimally and compare stability with the same large off balance piece. I am guessing there would be a wide range in performances.

I can dream anyway about how fun that test would be.

 

[Bill Boehme]

BTW, I am going to be picking up my AB at SWAT in a few weeks. JoHannes Michelsen will be doing some turning on it and said that he would measure my head for a hat. Right now, my head is feeling rather large so the hat may wind up being oversized after the swollen head syndrome gets back to normal.

 

[Charlie Knighton]

congratulations Bill, post a picture when you get it set up

 

[Bart Leetch]

The Vega lathe web site talks about using concrete as ballast.

Go to this URL...http://www.vegawoodworking.com/

Click on lathes then the Vega 2600 bowl lathe & read the second paragraph titled "CONTROLLING VIBRATION AND OSCILLATION".

 

[Odie]

The Vega lathe web site talks about using concrete as ballast.

Go to this URL...http://www.vegawoodworking.com/

Click on lathes then the Vega 2600 bowl lathe & read the second paragraph titled "CONTROLLING VIBRATION AND OSCILLATION".

Thanks for that, Bart.......

For the benefit of this thread, I've taken that paragraph and am quoting it here:

CONTROLLING VIBRATION AND OSCILLATION

Excessive vibration and oscillation become a problem when turning large and unbalanced shapes. While low RPM's are essential, having great mass properly placed and to use the best materials is equally critical. The most effective placement of mass is around the spindle center. Adding weight to the Lathe at any location helps, but as its distance from the center of the rotating turning increases, its effectiveness rapidly decreases. Adding weight to the base of a Lathe helps, but mainly to prevent walking or toppling. Materials to a lesser degree also affect vibration, mainly at higher frequencies. Cast Iron is somewhat better than steel in absorbing vibration, but concrete is 20 times better than cast iron. The Headstock on the 2600 is a 64-pound rectangular steel tube filled with 100 pounds of concrete. This combination has the very high strength of steel, and the unusually effective vibration absorbing capacity of concrete, with lots of mass surrounding the spindle.

It should be understood that just because it can be found in print, doesn't mean it has the authority of truth........however, I tend to think there is some truth there. I particularly tend to agree that weight close to the headstock is more effective for dampening vibration, than further away.

Interesting statement here about steel VS cast iron VS concrete...........

ooc

 

[Bill Luce]

BTW, I am going to be picking up my AB at SWAT in a few weeks. JoHannes Michelsen will be doing some turning on it and said that he would measure my head for a hat. Right now, my head is feeling rather large so the hat may wind up being oversized after the swollen head syndrome gets back to normal.

Bill,

Congrats.

I have talked to Brent a bit on the phone, in email, and in person in St Paul and I think his strong motivation for excellent tools and support will carry R well into this increasingly competitive turning market.

Having options is so critical to drive the market and the field is lucky to have such a truly dedicated player in the game.

And like everyone has said, he is a nice guy, too.

 

[Charlie Knighton]

For example in St Paul at first the AB at the R booth was a real hopper and posed a challenge. But after Brent loosened all the bolts between the legs and lathe body to allow the lathe to accurately "settle" and then retightened, the lathe was impressively stable for such a light lathe.

Bill, was this done with a load on or just a empty spindle running????

 

[Bill Luce]

Bill, was this done with a load on or just a empty spindle running????

Charlie,

I was having a bit of problem with a roughing maybe 14 inch blank (square, no corners removed) hopping around (the typical demo lathe problem), and Brent had me stop.

He loosened and then retightened the bolts between the body and the leg assemblies while the wood was on the lathe (not running) but I don't think the little bit of the wood mattered. It only took a couple minutes or less.

The weight of the lathe was able to settle on the uneven floor (as he said it would) and then the lathe handled that same blank very well. Then the biggest problem I was having (actually Brent was having as it was his booth) was that I had a hard time not throwing wood over the wall to the neighbor's booth. I am not a very neat rougher.

Bottom line is the lathe was then very stable, impressively so for it's size and weight.

If I have any info incorrect, hopefully Brent will jump in and correct me.

The Magma in their booth never was as well leveled and in spite of it looking bult like a tank was having stability issues due to the uneven ground. That is why I say how well a lathe is settled on the ground is the biggest factor in stability. I am sure set up right the big Magma would probably be extremely stable as well.

 

[Bart Leetch]

BTW, I am going to be picking up my AB at SWAT in a few weeks. JoHannes Michelsen will be doing some turning on it and said that he would measure my head for a hat. Right now, my head is feeling rather large so the hat may wind up being oversized after the swollen head syndrome gets back to normal.

Bill with an AB from R you'll need to wear an ACE Bandage from now on. You'll turn on the AB & up your head swells 24 hours later it'll almost be down & you'll forget & turn on the AB again & there you go.....ETC on & on again😀😀 & eating will be hard with such a wide smile too.😀😀