AWGB Woodturning Forum
General Category => General Discussion => Topic started by: howlingbaboon on September 14, 2017, 11:36:04 PM
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Hi All,
I'm considering mounting my AWVSL1000 on a bench instead of it's stand that it is currently on. When I've had larger pieces out of balance on for roughing out I've had it galloping round the shed like a crazy horse and the stand (sheet steel) looks like it's just going to crumple under the 97kgs (emergency stop!). I also get quite a lot of vibration even when a piece is round. Do you think it will help if I mount it on a sturdy bench instead or is it best on the stand which was made for it? I've been offered a good looking bench which could easily be boxed in to create storage and space for weighting. I guess I've got to raise it off the surface on blocks of some kind so that I can access under the bed to tighten up nuts etc.
All advice much appreciated, Cheers
Dave
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i saw on facebook that someone made a great bench out of scaffold poles to get rid of the vibration you have. they are bloody heavy so it might be better than a wooden bench.
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As Steve says weight is very important, my first lathe Axminster M900 had a sheet steel sand, I boxed this in and filled with damp sand, also bolted to the floor, it was never a problem. be careful not to exceed what the lathe is specified for though, sometimes our eyes are bigger than out bearings!!!!!!
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It's all down to weight, as Lazurus said. You can bolt the lathe to the floor, which removes the walkies, but if you don't dampen the vibrations, this will ultimately rip the bolts out of the floor. Weight, weight and more weight. And then add some for good measure.
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I will come at this from a different angle that goes against many other turners but based on basic engineering principles.
If something is out of balance it applies forces across the plane of motion. For woodturners that force converts into vibration as it moves the lathe. If you stop that movement, the force has not gone away, it is still there and will work on the next weak point, namely your spindle bearings and it WILL damage them.
When turning pieces that are either intentionally or just initially, out of out of balance it is much better to counterbalance the work, usually by placing weights on a disk mounted next to the workpiece. This gets rid of vibration and stresses on both the lathe and the turner.
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Yeah I thought about boxing it in and adding weight. I've got 2 large 16" blanks and another big log on the tool shelf to weigh it down but I don't think the shelf can take much more. Unfortunately, I don't think bolting down is an option as the floor seems to be a fairly thin layer of concrete. A mate suggested bolting it down to a big piece of ply and weighting that down but maybe the weight spread out wider with less downward pressure could be less effective. Here's some pics of the bench in question, needs a new top. It's bigger than my stand so if I box I in, I could get loads of weight in there. I thought that middle legs would add a lot of stability too.
P.s. I'm trying to spend a little more time with the chainsaw balancing the blanks before mounting now. Yeah good advice on not pushing my lathe too far, I intend to do the big ones on the Hegner in a workshop I'm a member of.
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Paul, I'm interested in knowing a little more about your counter balancing system. Could you explain a little more or maybe a pic or diagram, cheers
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So it's looking like the bench isn't quite wide enough. The bench is 48" wide. The inner 2 bolts on the lathe are 43" apart so they would fit on however the outer 2 bolts are 51" apart. This would leave me either having to have the bench top overhang by a few inches on either end or just bolt it down with the 4 inner bolts. Do you think either of these solutions would work or should I just pass on it?
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Hi
I've read this with interest and it seems to me you are pushing your lathe beyond what it's designed for. it's lowest speed is 500 rpm which is possibly too fast for roughing out large out of balance bowl blanks. I go down to 200 a 300 on mine if I have something like that to do (Nova DVR)
Also even when round a large blank will be out of balance because the density of the blank will vary. You can often see this as the piece will rotate such that the heavy part is at the bottom when the lathe is turned off.
As Paul says even if you fasten it down the forces at play will still be there.
Maybe worth considering upgrading your lathe to something designed to cope with what you want to do?
Cheers Dave
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I have the trade version of this lathe and have it on the proprietary stand like yours which I use for smaller work and at demonstrations. Though the lowest speed on mine is much lower than yours I still wouldn't try and turn heavy off centre pieces on it, I would do those on the Maxi-1 at one of its lowest speeds and can still get some vibration, especially if I have the head swivelled, if it is too big. If you try and make the lathe stable to minimise vibration etc I suspect that you would end up damaging the bearings or some other part of the lathe as it is a hobby lathe and not built to do the sort of work you are describing. The only answer tom your problem would be to invest in a much stronger bigger lathe or curb your ambitions I'm afraid.
Pete
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I agree with Dave and Pete on this. By the time you've purchased or made a bench, wood, screws, fixings etc only to find that the lathe is simply not up to the demands you are placing upon it, you would have been better off buying a heavier duty lathe. Electronic speed control, down to the low hundreds, will also make a massive difference; if nothing else because you can raise the speed slowly, instead of pressing the start button and standing back to see what mayhem results.
Remember, just because a lathe has a 12" swing, it doesn't mean it can handle large out-of-balance 12" logs.
If funds are a problem, I suggest you concentrate on smaller stuff for the time being, and try to use only well balanced blanks until such time as you can afford a better lathe.
Above all else, remember to wear face protection, especially important if you are turning large gnarly lumps of wood of unknown properties - you can not duck quickly enough to avoid the unexpected missile. DAMHIKT!
Safe turning
Duncan
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Hihowlingbaboon (Sorry I couldn't find your real name),
Paul, I'm interested in knowing a little more about your counter balancing system. Could you explain a little more or maybe a pic or diagram, cheers
I rarely use it as I try to get my blanks balanced before I start turning, either by trimming the 'blank' itself (removing 'lumps' and 'bumps'), or by moving it around on the centres until I find the correct centre of gravity. If I do use it, the 'system' consists of a ½" plywood disk, of close to max. 'over bed' diameter, mounted on the headstock, behind the chuck. The jaws are removed from the chuck as I am just using it as a massive 'nut' to hold the disk in place. I use a large spur centre into the Morse taper to drive the work and a live centre at the tailstock end. Now I can bolt weights into position on the disk to balance up the blank. Their position is determined by letting the blank find its lowest point, then you SECURELY bolt a weight at the 12 o'clock position on the disk, as near the edge as possible. The further out you can go, the smaller the weight needed to counterbalance the wood. I use an old set of kitchen scale weights drilled through the centre to take a 10mm bolt for the large ones, 5mm for the smaller ones. It's exactly the same principle as used by tyre balancers, when you have new tyres fitted.
You may need to change the weights as you work on the blank as the balance will change.
One very important thing - you MUST wear full face protection as you now have weights as well as lumps of wood rotating but we all do that don't we!
Hope that helps,
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Thanks everyone for the advice. I think the biggest I've made on my lathe has been about 10". The blank I described was out of balance because the original log must have been bucked at an angle resulting in one side of the endgrain of my blank sloping in and the other side sloping out. As I say, I've started trying my best to mirror both sides by making a sloping cut inwards with the chainsaw on the side that protruded out. The blanks are now much more balanced and the one I described turned fine after this. Don't worry, I'm saving the big blanks for the Hegner. I always use a full face shield.
I started learning to turn on the Hegner (after I'd had a taster on my dad's 100+ year old lathe). It's in a community workshop which is great with the only problems being the distance to travel and the committing nature of having to finish and tidy up in the same session (which can exhaust me). I certainly miss those slower speeds. Always seems odd to me that one has to pay more for a machine that will go slower (any way to modify it so I can go slower?)
I'd like to think that this lathe has a bit more mileage though seen as I've only had it a month or so. It also seems odd to me if a lathe with 12" swing and outboard tool rests, swivel head etc can't handle these things, what are the point of these features then? They are certainly used as selling points...
What were people thoughts on the bench connundrum?
Cheers
Dave
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Thanks for describing your method Paul. I'm sure it will come in handy at some point down the line when the other adjustments are no possible or for off-centre projects. Cheers, Dave
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Hi Dave,
Thanks for the name and glad to be of use. If you ever get the chance to see Gerry Marlow, he uses a similar system for some of his demonstrations.
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You can turn a 12" bowl or platter safely if it is balanced and the swivel is useful fpr tjurning as it means that you can rech inside them and hollow forms without having to bend awkwardly over the bed. They aren't just selling points that are not of real use. If you turn the lathe down to its lowest speed (500 rpm I believe on yours) and then slowly turn the speed up as you decrease the inbalance and / or weight you should be able to turn safely. If however the lowest speed still results in vibration then it is nor really safe, for you or the lathe. Any lathe has a limit and though you see turners on you tube turning huge pieces that are shaking all over the place they are accidents waiting to happen. The first rule in turning is always to turn safely. his means knowing the limits of both your own experience and the equipment you have,
Pete
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I am relatively new to turning and have a somewhat similar issue. My Woodfast M910 lathe (Australian made) is a solid cast machine but is mounted on a pressed steel cabinet which is only about 350 mm wide. This makes it prone to vibrating if the work is out of balance. A larger piece of wood only has to be a little out of balance to cause vibration.
Bolting the lathe down to the floor would be an option but I like to be able to turn with the work in good light (doorway) and move the lathe out of the way when not in use. I feel that a considerably heavier and slightly wider stand would go a long way to towards fixing my problem. The concrete floor of my shed is slightly uneven so the stand needs to be rigid with no flex and have a levelling leg on one corner so as not to transfer any winding forces to the lathe bed.
In my mind the two options are either a heavy steel frame or a heavy timber frame built using similar materials and joinery as a Roubo work bench. Weight can be added to the frame to increase mass. I use a pallet trolley to move my larger machines.
Derek Cohen built a light timber frame for his Jet lathe http://www.inthewoodshop.com/ShopMadeTools/AStandformyJetMiniLathe.html
I also am interested in how others have managed this problem.
Always try to get the blank as well balanced as possible prior to turning, chainsaw, run one side over a buzzer, cut it to a circle on the bandsaw and if still out of balance use an Arbortech wood carver on the angle grinder (blank mounted on lathe but lathe not going). Even so larger blanks can still be unbalanced when turned due to differing wood density.
Tony
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in my humble opinion it is part of the work turning unbalanced timber so it should always be done on the lathe (within reason of course) and i rarely trim too much off my blanks and just start slowly to get them and even shape before ramping up the speed. ok i admit i do have the advantage of a 360kg lathe but i still remember my days turning with a benchtop and an SIP lathe which were as light as a feather in comparison and you just had to take it slowly.
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OK, I'm going to try and bring back my initial query a little. I'm sure my lathe has it's limitations but I think the weakest point may possibly be the stand (yes I agree that the minimum speed is also a major limitation). The rest of the lathe seems to be very solid cast iron bed.
Could it be more stable on the bench I posted?
What did you make of my options?So it's looking like the bench isn't quite wide enough. The bench is 48" wide. The inner 2 bolts on the lathe are 43" apart so they would fit on however the outer 2 bolts are 51" apart. This would leave me either having to have the bench top overhang by a few inches on either end or just bolt it down with the 4 inner bolts. Do you think either of these solutions would work or should I just pass on it?
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Hi Dave,
How about a thick piece of oak, say 4", to fit under the lathe and on top of the bench, the right size to fit both? (Not the full depth of the bench unless you are rich, or have a very friendly timber source!) Bolt the wood to the bench and the lathe to the wood.
That would give you some weight to the bench, address the length problem and if you ever upgrade you will have a nice piece of oak to turn!
The only down side is you will probably have to reduce the height of the bench to accommodate the rise in height of the lathe.
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for me this is all down to mass. the setup you currently have obviously does not have enough when you turn large or unbalanced items hence the lathe going all hippy hippy shake on you when the limit is exceeded. adding extra mass will be part of the solution.
if you can get a really heavy wood in slab form like greenheart, ekki or cumaru and use them as a base like paul suggested, this will mean that the energy needed to exceed the limits again will vastly increase enabling you to turn larger or more out of balance pieces without too much interference from a wobbly lathe.
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Do you think that those ideas will work OK with the bench top overhanging the edges about 3 inches at either end then? I've then got to put some blocks down to raise the bed so I can access the nuts from the head, tail and rests underneath. These will also have to be partly attached to the overhanging bench top.
I've got a few pieces of strong wood which may be up to the task. 1" Ply, a 2" mahogany bench top which is long enough, and and an inch thick oak table top (which is probs not long enough whole). I've also got some recovered 3x3 oak beams which might be suitable for the blocks but I'd need 2 at each end either way I orientate them.
I'm leaning towards the ply as a base for the whole bench then a lathe-wide strip of mahogany with oak mounting blocks. What do you think?
I really appreciate all this advice guys! As you can tell, I'm no carpenter! :)
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as it happens i am a joiner so can give you any advice you need.
if you can increase the foot of the bench then the overhang of the top will not be too much of an issue but i would not use the woods you say you have as they are relatively light in comparison to what i'm thinking of. oak would be the heaviest out of what you say you have and that is only 45lbft3 whereas ekki is about 66lbft3. check ebay out for old reclaimed stuff from the coast. i do know of a source of ekki planking which would do the job.
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Seventhdevil, You obviously know a lot more than I do about wood seen as I'd never heard of most of them until now :) Now please correct me if I'm wrong (I'm learning here!)
I'm wondering if the overhang is such an issue seen as with the sliding headstock, I do most of my work towards the middle of the bed.
I'm also a bit confused (generally and specifically! :) ) Does the bench top itself have to be heavy or just rigid? Maybe they are one in the same...? I thought as long as the top was rigid, that I could then add weight to the bench itself, like sandbags etc onto the shelves underneath. I guess I'm worried (based on a quick ebay search) that some of these heavy woods could set me back more than a new lathe :) Although maybe your source is more affordable...?
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why not post a picture of your setup and i'll see if i can assist you.
yes brand new those woods can be bloody expensive but they will easily last 50-100 years when not in contact with the ground and the source i have was an old bridge built in the 90's.
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I've not got the bench yet but I've been offered it for free if I can make use of it. Here's a pic of it, the lathe and it's dimensions
The bench isn't quite wide enough. The bench top is 48" (1219mm) long by 30" (762mm) wide. The inner 2 bolts on the lathe are 43" (1092mm) apart so they would fit on however the outer 2 bolts are 51" (1295mm) apart. This would leave me either having to have the bench top overhang by a few inches on either end or just bolt it down with the 4 inner bolts.
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Being well over six foot tall, I decided to make a bench, with cupboards underneath. I used a kitchen work top for the bench top and I have used the current one for over twelve years now. The only snag is that it collects a lot of shavings and seems to attract all manner of jigs and incomplete projects. No idea where they all come from!
Ron
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There is another alternative: Leave the lathe on its stand, and put the whole assembly onto a base. The base adds weight of its own and can be loaded with additional weight. This is what I have done with my lathe, not so much for weight reasons, but for height (I am 6ft tall and the lathe on its own was just too low, probably designed for 5ft 6" people).
Now my whole assembly weighs around 200kg, and is (when needed) loaded with additional steel weights on the base, but let me tell you: if I do a seriously off-centre piece, it still walks about the workshop.
I really like the idea of putting a large disc behind the chuck to mount counterweights. Nifty!
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I cant help but feel, reading back on this thread that the issue of a stable lathe whilst extremely important is missing the issue of overstepping the lathes abilities. Its not just about the stand, its the size and type of bearings, quality of the castings and the general fir and finish of the lathe itself.
I started with a lathe very similar to that of the OP, boxed in the stand and filled it with damp sand, it cured all the issues described, but, was I pushing the lathe above its limits at times, undoubtedly.
I am now fortunate and have a VB36 which as most of you know is almost limitless, check google for some astounding items in both size and weight, again a but, I always start between centers, I always find the natural balance point of the blank, then I plan my turning around that. (Lyle JAMIESON explains this better in his videos than I can) It makes a huge difference to the comfort, and safety of my turning. No more rattle a thump as I try and even out a wobbly blank, once on balance I can zip the speed way up to start resulting in better cuts and more comfortable turning.
I think we have to keep in mind the limitations of the lathe, and the difference between our aspirations and abilities, be it by experience or equipment limitations. You can`t make butter with a toothpick!!
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All the comments about the limits of the lathe are absolutely valid and I fully agree with them. However, it should be pointed out that there are situations that require off-centre turning, which can result in unbalanced work. The biggest issue for the OP here will be the inability to reduce speed below 500rpm (which is way too high for a large unbalanced piece, even on a much bigger lathe).
I think the way to go here really is with the advice to have a separate disc behind the chuck with counterweights mounted onto it.
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All the comments about the limits of the lathe are absolutely valid and I fully agree with them. However, it should be pointed out that there are situations that require off-centre turning, which can result in unbalanced work. The biggest issue for the OP here will be the inability to reduce speed below 500rpm (which is way too high for a large unbalanced piece, even on a much bigger lathe).
I think the way to go here really is with the advice to have a separate disc behind the chuck with counterweights mounted onto it.
Hi Fuzzyturns, Thanks for the endorsement of my suggestion about actually counterbalancing the work. It won't address every situation but it's a relatively simple solution and removes a lot of stress from both the lathe and the turner. :)