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Discussion in 'Woodturning Discussion Forum' started by Wheelman, Sep 29, 2009.
Jack, Same thing as on SMC. Get the Delta.
Tex, your not going to let me get anything other than the delta are you! I'll think on it for a couple more days and see. I need to call Rockler and see if they have any Deltas in stock. They had a sale on them last month and may not have any on hand. Why am I always broke during these $%*@ sales!!! . Story of my life.
Noticed that Refueler on yet another forum decided on the Delta. Seriously, hope you will both (?) be happy with your choice. I rarely endorse or promote a product or idea (because I might be wrong), but the first year or more after getting a VFD/EVS lathe my confidence and learning curve improved tremendously.
Jack It's kind of an apple and oranges kind of thing. The Nova is a larger lathe and is $300 to $400 more expensive. The Delta takes up a smaller footprint and handles smaller work but for a lot less money. I have a 20" lathe but the vast majority of work I turn could be done on a 12" mini.
There are a lot of misconceptions about the VFD. I'm not an electronics engineer but have worked with them for quite a few years now. It has been stated that they do reduce the horsepower a little. I can't argue that. However in practical use they have plenty of power especially at the low end. That is because they reduce the frequency that the power hits the motor, they don't reduce the voltage or current. At least not so I can tell from turning with one. They do reduce the RPM but that's because they go from 50 cycles per second to much less, I think mine goes down to something like 6, which gets the rpm down to about 50.
DC motors on the other hand lower the power when you turn the speed down. Consequently at slow speeds they are way underpowered.
I've turned on both lathes and they are both excellent buys for the money you put in them. I think you would be happy with either. However once you've turned on a lathe with VFD it's hard to go back. You just turn a dial and you change speeds. No belt changes or cranking a big mechanical dial.
New Kid on the block has to be considered
the question was best $1500.00 lathe. While no one can argue the merits of the Nova 1644 or the Jet 1642.00 both which are more than 1500.00 here in 2010, the new kid on the block is the grizzly 18x47 model G0698.
It has all the features, like 2hp. variable speed , 3 phase, reversing, smooth and quiet operation, heavy weight, and quality pulleys, switches, wiring and machining; one would have to say that this lathe should certainly be in the running.
My experience so far has been very positive, and the track record of the lathe with other vendors such as Laguna, Hare & Forbes, and Busy Bee shows this machine is not a flash in the pan.
I believe that the quality is comparable to the Jet 1642 evs, only it has larger capacity both in swing and between centers. The PM 3520b has very similar features, and this lathe stacks up very well for the price.
The price of the Nova 1624-44 is $1200 regular price, but it does go on sale from time-to-time for much less. The DVR XP is the one over $1500, at $2200. I've had one for 4 years now, and think that it is a great, under appreciated lathe.
I think that we sometimes place too much emphasis on which is more important since they are directly related, but with a variable speed drive it can be confusing, if not misleading because of the way that things are advertised. Just to get technical for a bit, in order to do work (cutting wood in this case), power is required. Torque does not necessarily mean that any work is being done since the motor is generating torque even when it is stalled. Three phase motors designed for inverter duty are generally capable of producing full running torque at base speed and slower -- all the way down to zero speed in the case of a true vector feedback system. Consider, however, that a one horsepower motor can only produce three pound-feet of torque at base speed and it becomes easier to see why torque alone isn't going anywhere. Power, the product of torque and speed, tells us how much work can be done. With a variable frequency drive, this also means that below base speed (base speed is the 60 Hz speed), available mechanical power output is reduced proportionally with reduced speed. Lathes with variable frequency drives are going to wimp out at some point as the speed is lowered. Lathe manufacturers deal with this problem by using stepped pulleys having at least two speed ranges. The purpose of doing this is to keep the motor speed up high enough that adequate power to the load can be produced (remember that available torque is constant). Stepped pulleys are also important to minimize overspeeding the motor. This is straying off the topic a bit, but running the motor at very at high speeds is undesirable for a variety of reasons including reduced torque and power.
Torque is important when considering loads (such as loads on gear teeth in a drive train), but it is power that actually does the work. Torque can exist in a static situation where nothing is moving and no work is being done.
I think that while VFD drives are great, when someone is shopping for a lathe, it is important to recognize that everything has a down side that balances the good news. With stepped pulley drives, the advantages are lower cost and more power while the disadvantage is limited speed control. With variable speed drive, the disadvantages are cost and reduced power at slow speeds. The better lathes compensate for this with multiple speed ranges (we're back to stepped pulleys again) and larger motors (more money). So, it is important also when comparing lathes to recognize that higher horsepower motors on VFD lathes does not automatically translate to more powerful -- more likely it means getting back on an even keel with fixed speed lathes.
I forgot to mention that when using a belt drive system for speed control, since the available motor power is always the rated power, this means that the torque at the spindle is multiplied by the inverse of the drive ratio (as viewed from the motor end of the drive train). The bottom line is that the slower the spindle runs, the greater the spindle torque. Convenience is the only "advantage" that an electronic variable speed drive can offer. When there is money and power to spare, that may be sufficient reason to choose a variable speed drive lathe. I know that I would.
Great information Bill
Your last 2 posts on this thread have been particularly informing. It is great to have someone who can explain the dynamics of electrical function. It also explains many of the phenomina that we who do woodworking experience with our machines.