Possible warning to those that have the Grizzly G0698 lathe

[Ken Fitzgerald]

Dirk,

Take it from someone who has worked on some pretty sophisticated electronics since 1969, that speed control potentiometer was never designed to be used as an on/off switch. Further more, I would highly recommend unplugging your lathe when you aren't using it to prevent damge to the speed control by line voltage fluctuations or lightning strikes in the area.

Around 1973 at NAS Meridian, MS I saw what lightning running in on AC power lines can do to a precision approach radar used in air traffic control to land air craft in bad weather. It was impressive.

I have a PM3520B and I unplug it everytime I am finished turning.

Electronic circuits fail. I made a awfully good living working on MR and CT scanners and x-ray equipments that could cost up to $1,500,000 because electronics fail.

Use the switch not the pot. Unplug to be sure.

[dirk martin]

BTW I got a catch while working near the end of the tool rest and it broke like it was made of dried mud.

My tool rest broke exactly the same way, Fred.

[dirk martin]

Of course folks don't get into a HABIT of leaving their woodworking hardware on. That's just common sense.
My story, stemed from a MISTAKE, where I left it on over night. Similar to Mr. Chandlers mistake of leaving his on, while he rushed to an emergency. Nobody here is saying that they have a HABIT of leaving their hardware on.

It's also not smart to leave your car ideling in your driveway, unattended.
But if you did, I think EVERYONE would agree, that it should stay ideling, and not rev to full speed on its own.

[dirk martin]

Absolutely NOT! As an electronics technician I know that essentially all electronics circuits are sensitive to temperature, resistors especially and it is a variable resistor that controls the speed. The off switch on many of these boards does not even cut power to the circuit - unplugging it is the only safe way to be sure that power is off and that the motor can not accidentally power up.

If that's the case, then turning the machine OFF, and leaving it that way, is unsafe.
Sounds like most of us have some very unsafe shops. I'll bet very few of us (yes, I realize some of you do), but very few of us, leave our shops with every single device unplugged.

[dirk martin]

Dirk,

Take it from someone who has worked on some pretty sophisticated electronics since 1969, that speed control potentiometer was never designed to be used as an on/off switch. Further more, I would highly recommend unplugging your lathe when you aren't using it to prevent damge to the speed control by line voltage fluctuations or lightning strikes in the area.

Ken, you say to unplug my lathe....
Actually, are you recomending unplugging every single woodworking device in my shop, when I'm done using it for the day? How about when I'm done using it for each task?

I mean...seriously, folks.... Do some of you disconnect your battery terminals in your car, when you park it in your garage?
Are you suggesting that an on/off switch should read "on/off...usually." ?

I'm simply pointing out a potential issue with this lathe, that could injur someone.
If it is "best practice" to unplug your woodworking hardware from the wall, after each use, then it would read such, in your manuals. After all, the mfg stands to lose a lot, if their switches read "off", and it was not unusual for them to not remain so.

[Salvatore Buscemi]

If that's the case, then turning the machine OFF, and leaving it that way, is unsafe.
Sounds like most of us have some very unsafe shops. I'll bet very few of us (yes, I realize some of you do), but very few of us, leave our shops with every single device unplugged.

Yeah but, it's safer than leaving them on with only the speed turned to 0.

[Don Alexander]

Dirk;

i understand what you are saying and i refer back to my last comment that perhaps its time to step back and take a deep breath or 6

that is not criticism just some friendly advice and i'm glad nothing worse happened

[Cecil Walborn]

Personally I had problems with my G0698 when it came and I set it up it would run then shut down on me. I would shut it off and then it would not start for me. So called and they said they would call back in 24 hours 48 hours later I called them again, this time they said they would send me a new headstock. When I came I had to ship the old one back. Would I would be using the new one it would lost rpm's on me, it would go down 50% in rpm's. Again I was on the phone, again they would call back in 24 hours again I had to call back in 48 hours cause not one called. This time they have not heard of that happening. So they would repair it but they had no parts so had to wait for parts. I said I can not afford to wait, so we agreed to exchange for the G0632 lathe which so far is running great and without fault. My wife works in a warranty company and the Toshiba circuit boards are the ones that fail the most of all the boards used. So I am glad I do not have it any more. So I guess I got one of the few that was bad.

[dirk martin]

I fully agree.

[David Campbell]

Sound as though you have a problem with your software turning your SCR's on when it shouldn't. I have a Nova variable drive with a D.C. motor and experienced the same problem. I replaced the solid state electronic board and it resolved the issue.

[dirk martin]

Thanks Don.
I am not taking any of this as criticism. Often times it's hard to get emotion from the written word...but I'm really not taking any of this a criticism. I understand folks are simply trying to avert danger and injury. Much the same as the reason I started this thread.

[Ken Fitzgerald]

Dirk,

On most AC variable speed controllers, even when you use the off switch certain circuits are still energized. So if you leave it plugged in and a power surge or sag occurs it can damage those circuits that are still energized.

That's why when you plug my PM3520B in, it takes a few seconds for capacitors in those circuits to charge and if you immediately turn it on after plugging it in, it won't spin the spindle. If you wait 3-5 seconds after plugging it in, then turn it on it works fine. That's also why my speed indicator indicates "0" rpms even after depressing the off switch. Certain circuits still have power. Leaving it plugged into the wall can allow it to be damaged by incoming power irregularities.

Most of the tools in my shop don't have electronic controlling them, thus I don't unplug my drill press or my SCMS....

However, since I have a RF remote control on my DC, I throw the breaker on it if I'm leaving town for a few days and I always unplug my lathe because those two are controlled by Electronics.

Speed control potentiometers are never meant to be used to shut equipment off UNLESS they have a switch designed into the pot. Using the speed control to turn it off is not using the pot for it's intended purpose. I don't believe manufacturers should be held responsible for a consumers misuse of a tool.

[Thom Sturgill]

If that's the case, then turning the machine OFF, and leaving it that way, is unsafe.
Sounds like most of us have some very unsafe shops. I'll bet very few of us (yes, I realize some of you do), but very few of us, leave our shops with every single device unplugged.

Turning it off and walking away is OK. I do that myself. The equipment is designed for that. That does NOT mean you are protected from surges wiping out the electronics which are still under power. Turning it off and doing something that would be hazardous if it accidentally started IS NOT, and I'll bet the manual DOES say that. Turning the reostat down and walking away is a total NO-NO IMHO.

Most modern electronics consume power when 'off'. They refer to that as 'vampiric', and many people ARE recommending that you unplug when not in use. And they mean everything. A bit extreme, but will save you money in electricity and repairs if you live in a lightning prone area.

[Ken Fitzgerald]

Turning it off and walking away is OK. I do that myself. The equipment is designed for that. That does NOT mean you are protected from surges wiping out the electronics which are still under power. Turning it off and doing something that would be hazardous if it accidentally started IS NOT, and I'll bet the manual DOES say that. Turning the reostat down and walking away is a total NO-NO IMHO.

Most modern electronics consume power when 'off'. They refer to that as 'vampiric', and many people ARE recommending that you unplug when not in use. And they mean everything. A bit extreme, but will save you money in electricity and repairs if you live in a lightning prone area.

Agree whole heartedly Thom!

[dirk martin]

Dirk,

I don't believe manufacturers should be held responsible for a consumers misuse of a tool.

Good discussion.
Ken, are you saying that you feel the turning of a potentiometer to zero, and expecting the spindle to stay at zero RPM, is tool misuse?

Are you saying that if a lathe user leaves the lathe ON, and the speed control at zero, and then finds the lathe spinning at full speed in the morning...that he has misused the tool?

The user probably wasn't being wise, but did s/he "misuse" the lathe?