Discussion in 'Woodturning Discussion Forum' started by Scott Regenbogen, Jun 27, 2009.
Probably the difference in price between the DVR and a 3520b. Minus 2 inches of swing of course.
I have the outrigger for mine, 29" bowls are possible. The rotating head stock makes hollow forms very comfortable.
Aaron, probably correct on your assumption. However If anyone ever gets down San Antonio Way just give me a PM and anyone is more than welcome to go for a test drive. It really is a different machine when mounted on a healthy stand. I only have one rule you cannot make fun of my messy shop or old wreck of a house.
In reality, while big blanks come around every once in a while most of the stuff I get is less than 16" and and mostly in the 12" range. When the larger piece does come around I have my outrigger. The pivoting head stock is really a space and back saver.
With the unit wired 220V its power is fabulous. While most say that its is 2HP when you dig in the manual in reality it is rated at 2.3HP which is close to a 3rd of a horsepower more. At first I thought I would hate the controls but after using the 5 presents and then the ability for fine adjustment I notice no significant difference over a knob.
I have nothing against the PM or the Jet. I almost purchased a 3520B which I agree that it is a great value. I would love a Stubby but that money goes with my little boy to private school. My biggest consideration was footprint. I wanted decent capacity in both swing and bed length but need a small footprint. IMHO With the stand I built I am not sacrificing anything over the 3520B except the swing over the bed and there are some things I like better like the rotating head stock, DVR technology, and the extra spindle capacity when needed. And like I said the swing away bed segment makes a great place to park the tailstock when not needed.
I am really not a fanboy for Teknatool other than I have been very satisfied with the products I have purchased. I would probably be just as happy with a PM or Jet. However with the sale at Craft Supplies and if you need a compact capable package, and have the ability to build your own stand or get the cast Iron legs I think it is also a good value.
We have a DVR and like it. I agree that the button up/down for speed in a pain sometimes and it is slow to start in reverse with an electronic warning. For some models they have an up-graded panel with a dial for speed ($149) and a wireless remote. Good deal if you can find a nice used one.
Since we are starting to turn bigger items, we are looking at a 3hp machine.
I have had 2 Nova lathes and loved them. My only problem with the DVR is that motor. If it dies your in trouble. I bought my Powermatic (and the jet would have the same advantage) because every part on it that could go bad could be either replaced by an aftermarket device, or rebuilt by a good machinist. I've seen a lot of lathe manufacturers go by the wayside over the years and I plan to own this for a long time. I want either parts availability or to be able to have the parts made in case the company does go belly up. I believe there was a lathe called silverdyne or something like that. Came from overseas and had a spindle motor like the DVR. I think David Ellsworth had one for a while. Haven't heard from them after just a few years of a lot of ads. That's part of why I say what I say. Delta used to be a great company. Now you can't get any parts. Things change fast now days and that worries me as far as buying equipment. Much smaller than most lathe companies but Monster tool just went belly up.
John are you thinking of poolewood? I know David used to sell poolewod lathes.
Yes, that is what I also was thinking. Bill Grumbine also had one.
Well actually there were two. The poolewood that I forgot about and one that looked similar that was only sold in Europe I think and it had a name somewhat like Silverdyne.
Does anyone know where to find a detailed description of the theory of operation of DVR (aka Smart) motors?
If you do get the DVR with the extension use it as an outrigger also like this guy. Put on the lathe when needed for long items or put on the outrigger, AFAIK it is only four bolts.
Ignore the chainsaw, rasp, and 600 rpm.
Skip over to about 3:25
Digital Variable Reluctance is just a fancy name for stepper motors. If you search for information on the theory of operation of stepper motors, you will find lots of information on the web. Calling them "smart" is marketing speak. Steppers aren't able to run by just applying power ... they can only run by having a digital processor tell them what to do ... one tiny step at a time. And, there is always a tiny amount of vibration inherent in that type of motor. On the positive side, they are great in industrial automation where programmed precise control of speed, position, and direction sequences are needed. For human in the loop woodturning those really aren't design features that give them an advantage over other motors except for special applications such as where you would want to build an ornamental lathe using a stepping motor for indexing. Another positive thing about steppers is they are very simple and therefore are low cost if you don't include the cost of the electronics that are needed.
Another type of motor that hasn't shown up in woodworking machines yet is what is known as brushless DC motors (usually called BLDC motors). They really aren't DC motors ... they're actually more like three phase AC motors with built in Hall Effect sensors for controlling how power is switched. They are fed with pulse width modulated power to simulate three phase AC power much like a VFD is used to drive a three phase AC motor on many lathes. The thing that makes them somewhat like DC motors is that the the rotors have permanent magnets instead of windings ... but not just any magnet, they use rare earth ceramic supermagnets (samarium cobalt for example). They are able to output a lot of power from a very small motor. The bad news is that they are very expensive.