OK, help me choose a new lathe

[Andy Hoyt]

.... But, when a big (and, in my opinion, reputable) company says their gee-whiz machine has a two-horsepower motor, I pretty much accept that as honest representation. Is there no standarization in this madness? ....

The honest representation ends when the designers and engineers pass it off to sales and marketing.

[Brad Hart]

all I know is there is no way I would put this piece of wood on ANY entry level lathe.
Bill

Your are right any unmodified entry level lathe. The Speed and stability of cheaper models including the jet 1442 are not such that what you are doing is really possible with them I have turned a similar piece to what you are doing on a 1442 that was about half the size and even at its lowest speed setting it litterally shook the piece apart. This shape is not easy on the less sturdy lathes. For me to do these pieces on my modified lathe (I can do one about 15") it takes turning it down to 150 to 200 rpms taking very shallow cuts.

The one thing I think you and I agree on is most lathes can make a nice quality piece it simply is a matter of maximum size your lathe will handle safely.

[Henry C. Gernhardt, III]

A quick aside on horsepower...

I wasn't trying to bash any product---grizzly, harbor freight, craftsman, or any other---in making the comment about apparent versus real power. My thought was simply that if they're quoting volts times amps, then that's not going to be the true power.

About the only way you're going to truly determine what the shaft horsepower is on a motor to any degree of accuracy is to hook it up to a dynamometer. This device can directly measure shaft horsepower.

Another issue: Torque. Some motors are designed for torque, some for horsepower. A high-torque motor can turn much heavier loads at much slower speeds. A high-horsepower motor will be able to turn things at relatively high speeds, but won't be able to handle massive things very well.

Think about this: You have an F-350 with a 5.0L Cummins Turbo Diesel, and an F-350 with a 5.0L gasoline engine. Unloaded, the gasoline engine will smoke the diesel in a drag race (more horsepower in the gas engine). Now, let's hook'em both up with a gooseneck 6-horse slant-load trailer, and load the thing up with clydesdales. The Diesel truck will be able to take off more smoothly, and sustain better speed on inclines, due to the higher torque of the diesel as compared to the gas engine.

My point(s):

My question about your motor, Frank, was mostly academic. I find it interesting that a manufacturer/supplier would quote apparent power as the power of a motor, however I understand that there are a great deal of vagaries in trying to determine shaft horsepower without a dynamometer.

My point on Torque vs. Horsepower? Bill's Vega, with its heavy construction and high low-end torque, not to mention sturdy bearings, is going to be able to handle the large, out-of-balance pieces. Horsepower and torque go hand-in-hand to a certain extent, but the heavier and more out-of-balance things become, the more torque you're going to need.

[Frank Fusco]

Frank, Stu has explained it pretty well with his motor pic, but here is another illustration for you. I have been working on this piece today. It started out at 25" from tip to tip (and still is) and about 1 1/2" thick. It is, as you can see, very irregular, not to mention fairly heavy. It is mounted on my Vega bowl lathe, which sports a 2HP 3 phase motor. Now, I am not far behind you when it comes to understanding this stuff, but all I know is there is no way I would put this piece of wood on ANY entry level lathe. Even if you could balance it to keep the lathe from literally falling over, it would tear the headstock apart in fairly short order. Cutting would be almost impossible since every time you would touch the gouge to the wood, it would stall the machine. I left the Vega set on the high range because I was too lazy to move the belt and I wanted the faster rpm once I got it (better) balanced. Top speed was around 350 rpm for a lot of the initial work. Then I got it up to almost 800 rpm for my finishing cuts. Even with the lathe I have I had to take it easy with the cutting out on the edges, and I had to keep the speed down to keep from shaking the lathe around the shop.

Bill

No argument on that from me. I believe what we have been talking about is perspectives from two different worlds. Not many turners even attempt very large bowls and would not have a need for the $4000.00 Maximus Gigantus lathe. I am only Oh-Hum impressed with the big dollar lathes I have seen. (that's only a few) The big all-in-one power head/spindle headstocks seem to spend more time in shipment back for repairs than in use. And, one in particular, owned by a friend, out of warranty, costs more to repair each time than a new $400.00 Grizzly. Until recently, my turning club had a member who was (still is) a professional bowl turner. His bowls sell in art galleries in the $3000.00 range. Until recently he used what many would call 'entry level' and still turned his beautiful bowls and vases. Then he got a big dollar something lathe. When asked about it, he shrugged his shoulders and said "It's a lathe". He doesn't get anymore money for his bowls now. Maybe if my ship comes in, less likely every day, I'll consider a big dollar upgrade. But, for now, color me 99% happy with my Grizzly. One day I tell why it isn't 100%.

[Brad Hart]

I find it interesting that a manufacturer/supplier would quote apparent power as the power of a motor,

I have never seen a tool motor no matter how much it cost quoted at anything other than apparent power of amps x volts divided by 748.

[Stu Ablett in Tokyo Japan]

Maybe I'm beating a dead horse here, but I'll give it one more try.

The top of the line lathe will do things that your $400 Grizzly lathe can only dream of.

If I, as a turner, wish to do these things, for whatever reason, then your $400 Grizzly lathe is a waste of money, to me.

The expensive lathe is a bargain.

Here is another comparison.

When they were constructing my building, the guys doing the re-bar in the concrete had a machine made by a company I'd never heard of (nor can remember) and this thing was designed to do one thing, cut re-bar. It was big, a bit heavy, but it was portable, and ran off a 18V rechargeable battery. I was a hydraulic clipper.

It had a set of jaws on it that each jaw was about 2" thick and had the shape of the re-bar in it. The re-bar I'm talking about is 1 1/2" thick, or maybe it was slightly thicker than that. They had to clip the ends to join on new pieces (7 story building) this machine was put on the re-bar where you wanted the cut, the first trigger was pulled, the machine grabbed the re-bar on both sides of the cut, then the second trigger was pulled, the thing started to cut, took a good two minutes for the cut. When done, the cut was mirror smooth and a perfect 90.

I looked at that and asked why they did not just use a cutting torch, or even a plasma arc torch. They told me that each method was way too slow, and did not leave a nice enough cut for the joint, so they would have to then spend time grinding the cut smooth. I asked how much the machine cost, they told me just under Hyakuman, which is just shy of 1,000,000 yen, or about $10,000 US

Now came the kicker, the took a second machine, lined up the new piece of re-bar above the just cut one, they attached the machine to the two pieces, and then turned it on, (this one was run by a BIG portable gen) this machine mashed the two ends together, and ran a HUGE current through the joint, welding them together in about 30 seconds, the joint was stronger than the metal that surrounds it.

Sorry to be so long-winded but my point is that for these guys, a torch and a grinder would cost them money, having the right tool, an expensive one at that, saved them money.

Frank for what you are doing, it sounds like you have the right lathe, but for many other guys, that lathe is not good value.

You have mentioned these expensive lathes that constantly break, and are expensive to repair, I'd really like to hear the brands, and what exactly broke, just in the interest of avoiding these products.

Cheers!

[Joe Tonich]

Maybe I'm beating a dead horse here, but I'll give it one more try.

You wouldn't be the only one Stu.......

[Frank Fusco]

Mabey I am beating a dead horse here by reviving this thread. I was curious about an early post slamming the Grizzly G0462 horsepower rating without reference to any facts. Also, I am not well versed in things electrical and was curious as to what Grizzly meant by "2 horse power". A post with an early reply only partially explained things. Then, others here chimed in with lengthy explanations and pictures of motors that really muddied the situation. For me, more confusion was added recently when I visited a large tool store in Little Rock, Arkansas. There was a display of electric motors. One, a 3/4 hp. dwarfed at 2 hp right next to it. Go figger. I don't understand. Anyhow, I received a reply from Grizzly that satisfies me. It is quoted in it's entirety as a copy and paste below. Please note, the responder is a fellow SC'er.

<<<Dear Frank,

Hello, your request for information was forwarded to us from our PA location. We've seen you around on Sawmill Creek and appreciate your comments - Thanks. As for the lathe question, the motor on the G0462 is a 1725 RPM, single phase, capacitor start, induction type (AC, not DC). The nameplate rating is 2hp, and I assure you it provides far more power than anyone would ever need on a lathe this size. Just ask anyone who actually owns or has used this lathe and they will verify it's robustness (Think V8 in compact pickup. It's more power than you need, but it sure is nice to have) ;-) . It uses a simple and reliable reeves drive to vary the speed (variable speed pulley), so there is no AC inverter or associated power losses. I hope this answers your question.

Sincerely,


Matt Carleton
Quality Control
Grizzly Industrial Inc>>>
</PRE>

[Frank Fusco]

No one asked me, but in an earlier post I said I was 99% pleased with my Grizzly G1067Z lathe and if anyone asked, I would tell why not 100%. But, I'll change that to more like 97% pleased. And, even though no one asked, I'll explain the defieiencies as I see them.
#1: The non-standard 1"X12tpi spindle. Hard to find adapters for this. Newer Griz lathes are now standardized with the rest of the world.
#2: The Reeves drive variable speed control requires changing speeds only when running. This may be a common feature of all Reeves drives, Griz or not. But, for a lathe, I don't like it. If one should forget to put on slow and then mount a large, heavy, pre-bowl blank and hit the start button while on high speed, one could be replacing a mouthful of teeth. Solution, of course, is to get in the habit of putting on slowest setting at end of every project AND double-check before mounting new work. But, I still don't like it.
#3: The speed control handle, when at highest speed intrudes into the work zone and can interfere with the workers hand or tool handles. Two extra minutes of engineering would/could correct this. For whatever insane reason, this defect continues with later models. I think some Chinese engineer is a sadist.

Other than that, for the dollar value, the Grizzly IMHO is the best lathe available on the market. Granted, it is not a 1500 pound, $5000.00 monster. What it is is a $400.00 lathe that will do whatever anyone wants up to it's 14" X 40" capacity.

[Frank Fusco]

I may be grave digging on this issue but the original thread both bothered and confused me. An experience today may have brought some clarification. The motor on my Grizzly lathe (see: "bad motor" thread) just wouldn't work for me. To shorten the story, the electric motor shop where I go is owned by a fellow who has been building and repairing motors for 55 years. He said that many foriegn motors (he dislikes Tiawan stuff) use the amprage forumula to determine horsepower. He says that for a more accurate idea of power, just divide by 2. The reason, he says, is that about 50% of power is lost to inefficiency of the motor. He says that American motors are tested for actual ouput at the shaft and those readings are more realistic. However, after saying that, he paused and added "American motors seem to be getting pretty sorry these days". So my original question finally has been answered. Is there no standardization? Answer: No.

[Harvey Schneider]

Stu
2.2KW/.746=2.94 HP almost 3 HP

Power out of the shaft isn't necessarily equal to power into the windings. When I worked on high speed brushless DC motors (3 HP 26,000 RPM) it was hard to get better than 70% efficiency.
With an induction motor in addition to the eddy current losses (current induced in the laminations that does no useful work), windage losses, vibration losses, bearing losses and wire losses (wire resistance makes heat not magnetic field) there is the phase angle between voltage and current due to inductance that limits the real power that can be extracted from the shaft (real power = volts x amps x cosine phase angle).
Motor manufacturers are also fond of quoting peak horsepower which is a really useless spec.
Buying quality is like buying oats. If you want nice, clean, fresh, oats you have to pay a premium price for them. Of course, if you are willing to put up with oats that have already been through the horse, well, they come cheaper.