I'm apprehensive about putting some 17"-19" dia. 4" to 8" thick wet NIP blanks on my VS N3K with the headstock rotated and no tail support. I've stressed mine before, but what is the experience & advice from you engineers and those who have far exceeded the lathe's design limits?
My lathe stand, faceplates, toolrest etc. will be OK and I'll start up from zero, but If things go wrong what likely happens to machines that are far overstressed? A cracked head casting, ruined bearings or what?
I know, I know....give the blanks to a Stubby owner or buy one Arch, but in the meantime....
Cut the blanks in 2" slabs, proceed to cut in to rings, then stack, glue etc., you know the drill !! Then again you could just go at it very carefully, and if your VS N3K does give up the ghost, well than maybe you will have to UPGRADE HiHi. You can't take it with you even if you like !!!
Here's text from an old article of mine. Not quite on the mark for you, but perhaps something in it will prove useful.
Turning Big on the Nova 3k
A few people have contacted me having trouble finding my earlier comments about turning larger pieces on the Nova 3k, so I thought I'd update and repost this as a separate thread.
Here's how I manage to use the Nova for large pieces.
Balance the log as well as possible both before and after mounting it. My Delta 14 inch bandsaw (plus riser) simply won't handle big logs well or at all, so I usually use a chain saw. Though some might not approve, I've often taken a 16 inch electric chainsaw or a Tiger Saw (Sawsall) to the log, even after having it mounted (or nearly so) on the lathe. A fairly well balanced log is essential (well, at least highly desirable) when using a smaller lathe like the Nova 3k. Don't hesitate to take a big hand chisel and knock off a few corners. It will be a lot easier to do this with a hammer and chisel, then have those corners banging against your gouge later on.
I have my Nova on a custom built stand that is a combination of cast iron and hard maple. The stand with its sand filling weighs in at over
600 pounds (without the lathe). It has a base of 22 inches by 50 inches. The whole lathe is bolted down to a 3 inch maple top that is 24x60 inches. Since I later added an extension bed, I have that separately supported at its end with a 2" pipe and flanges.
I use the Nova outrigger. I suspect this makes a real difference since it allows the headstock bed to be bolted down on both sides of the headstock. I think this greatly adds to the rigidity of headstock. For those who don't wish to use the outrigger, I suggest obtaining the thickest available 4 inch angle iron and doing the same.
I use a 1.5 hp Leeson DC motor which allows me to turn at slow speeds with plenty of torque. The extra weight of the motor may help counterbalance the larger logs as well. That said, I don't hesitate to move the belt down to the lower pulleys. I often leave mine set for a maximum speed in the 600 rpm range.
For 11-18 inch logs, I always rough out using a Oneway Cast Iron faceplate (either 4 inch or six inch depending on the size of the log and the form desired) using lots of Robertson head sheet metal screws (Craft Supplies is a convenient source for these).
I always bring up the tailstock when, and for as long as possible. Since, IMO, the tailstock is the weakest link on this lathe, it try to use the least quill extension possible. I usually use the optional Nova interchangeable point live center as it provides extra extension and has a fairly good bearing. A Oneway live center probably would be even better.
Even though I use a faceplate, I put a drive center in the headstock spindle to help rigidify the spindle. The drive center has been ground down to fit flush with the faceplate.
For large pieces, I really crank down on the headstock locking screw. If you ever have reason to have the headstock off, it's probably a good idea to go over the headstock and bed faces with a file to make sure that they are level and without any large ridges or flash that would interfere with solid contact between the two faces.
The outrigger, while not essential, can sometimes come in handy to work the headstock side of larger diameter (particularly if they are longer) pieces, as the standard banjo is relatively short. The outrigger is, of coarse, essential if you want to rough out or work on pieces larger than 16 inches. I've found the standard toolrest to hold up just fine, even after some awful smacks from a 3/4" Glaser Gouge.
This arrangement makes the Nova work for me with pretty big pieces. I don't argue that some have experienced vibrations with wood as small in diameter as 10 inches, but would suggest that following the above recommendations is likely to overcome their problems.
That said, the Nova definitely has it's limits. I've turned a really large log (around 22-23) inches, and despite all my other measures, this was simply too much for the Nova. I made it work, but I was stupid to have done it (all the more so, as this was the second time I'd done this). The Nova is not a high end lathe, and even following the above recommendations IMO is not suitable for regular use on pieces much over
15 inches (Of course, up to 30 inch in diameter thin table tops are quite feasible with the outrigger.) Frankly, I don't really enjoy working with things much over that size, and I'm not sure I would enjoy much larger pieces even if I owned a bigger lathe (of course I'd be happy to test this out if someone wants to donate a Poolewood 2000 or Stubby). That's not to say that larger lathes don't have other advantages as well. But for many of us, the Nova has the right range of features at the right price. Even if money were not a deciding factor, size and other priorities may rule out a large lathe. So for those who already have or are considering a Nova 3k, just know that the above has worked well to allow me to turn what I consider to be some fairly large pieces, and to do so in a way that has been enjoyable. As always, YMMV.
Lyn's advice on this is good. The Nova should be able to handle a 20 to 25" piece of wood with no problem so long as the wood is balanced. The larger the piece, the faster the speed, and the greater the unbalanced force the greater the vibration. My guess it the bearings will give out first but if you hit the right harmonic frequency you could work fracture the shaft. I think that before you get to that point evey Lyn's 600 lb stand will start walking across the floor.
I have cut pieces up to 18" with my DRV and have had no problem so long as i do the prep work on the wood and take it slow.
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