Turning off a Variable Speed Lathe

[Brian Horais]

How many of you turn your variable speed lathe down to zero RPMs before turning it off? I make this my everyday practice, but I have heard some turners just turn off their lathes with the on/off switch, independent of what the speed is set for. I like to know that my lathe will not be turning when I 'power up', so I set it to zero RPMs when turning it off. I think of this as a safety item. What are your thoughts/experiences?

 

[Lamar Wright]

You know Brian, I really never though about this subject until you mentioned it. I guess it is by habit that I always turn my VS to 0 rpm when I am finished for the day.

 

[Gary Beasley]

My Nova has a digital readout that shows the speed its set at whether its running or not so I never worry about it, and it cant be turned down to zero, 100 is the lowest it will set. I can see whats going to happen before I hit the start button.

 

[GRJensen]

I'm a 'turn the pot to zero' guy. Goes back to my days in radio where I was taught to turn the pot down on my mic to avoid the switch pop from getting on the air.

 

[Dean Center]

I admire your discipline but must admit I just punch the button. I adjust the speed before I turn on again, but your way is clearly the safer one.

 

[Gerald Lawrence]

I just cut it off and unplug. I have noticed that the speed does not ramp so fast that even with my reflexes I can get to the speed control and change it. Now to qualify that statement if I have a larger blank I do lower speed before power gets turned on.

 

[Roger Wiegand]

Mine doesn't go to zero, so it's not a choice. My brain only has room for a limited number of rules, so I always check the speed before turning the lathe on. That seems more important than what it is set to while it's off.

 

[Mark Jundanian]

Another Nova DVR user, so different opperation. If the electronics are off (not just the motor) I have it set up to default to 300 RPM when powered up. I also have it programed to ramp up to speed over a second or two, so if it was last used at a higher speed setting it doesn't just blast off when I hit the start button.

 

[John Walls]

I have trained myself to turn the lathe speed to zero before hitting the switch. I have also got into the habit of flipping the breaker off when not using for more than a few minutes. The box is right behind the head stock so easy to hit.

 

[Mike Amphlett]

Not really given it much thought, but probably do both. But back in the "old days" you didn't have much choice, depended on how many many steps you had on your lathe's pulleys, it always start at a preselected speed.

 

[John Dillon]

Personally I'm in the habit of hitting the off button first and foremost whenever shutting down. I think it should be an instinctive reaction for shutdown. I'm in the camp where you turn the speed dial down prior to start-up. Just my habit.

 

[John Torchick]

My Rikon goes down to the minimum speed on the VS dial. I turn it all the way down so I don't mount a piece and start it at WOW! speed.

 

[hockenbery]

Whenever I teach I routinely inspect all the lathes for belt position and speed dial Fully counterclockwise.
also have the students check the belt position and speed.

I have a good friend who suffered a severe hand injury from a student’s bowl.
The class was NE Bowls. The lathes had reeves drives. The student had finished a bowl on a suitably high speed and mounted a new blank without turning down the speed. The blank shot up 12 feet before my friend who was rushing over could reduce the lathe speed. The descending bowl hit is hand. 20 years later one finger still doesn’t work right.

 

[Brian Horais]

Great replies by everyone! I think we all have safety in mind when working around our lathes. Surprises can sometimes be very harmful, as you pointed out in your post, Hockenbery. I took a class once and pointed out my theory to the instructor on turning the lathe speed down to zero before shutting it down. He responded that he never does it because it will wear out the speed control. My view is that speed controls are replaceable (although I doubt the control will wear out), but body parts don't readily heal (if ever).

 

[John Torchick]

Great replies by everyone! I think we all have safety in mind when working around our lathes. Surprises can sometimes be very harmful, as you pointed out in your post, Hockenbery. I took a class once and pointed out my theory to the instructor on turning the lathe speed down to zero before shutting it down. He responded that he never does it because it will wear out the speed control. My view is that speed controls are replaceable (although I doubt the control will wear out), but body parts don't readily heal (if ever).

Yes, parts for antiques are even harder to find.

 

[hockenbery]

responded that he never does it because it will wear out the speed control.

Surely he was joking....

 

[robo hippy]

I just hit the off button. Most of my turnings are bowls. When I prep a bunch of wood, they are all different sizes. At start up, I turn the lathe on and have my hand on the speed button to adjust instantly as or if needed. I ALWAYS do this, on automatic. I did hear a story about Dave Ellsworth sending a blank through a wall at one of the early AAW Symposiums in Davis, CA years ago. If I am turning a bunch of pieces the same size, I don't check the speed....

robo hippy

 

[Bill Boehme]

I took a class once and pointed out my theory to the instructor on turning the lathe speed down to zero before shutting it down. He responded that he never does it because it will wear out the speed control.

And, using the lathe will wear out the motor, belt, power switch, bearings locking levers, tailstock crank, ........

My first lathe had a Reeves drive so it didn't take too many missteps to do things the right way ... meaning turning the speed control down to minimum before stopping. For those who aren't familiar with Reeves drives, one of the idiosyncrasies is that you can't move the speed control lever unless the lathe is running. If you shut the lathe down with the speed control at maximum RPM and then mount a large heavy unbalanced blank things can be pretty exciting while simultaneously ducking for cover and lunging for the speed control.

My normal practice is to turn the speed pot down, but sometimes I just want to momentarily pause to check things out .... in which case I will just hit the stop button.

 

[Tom Gall]

I usually turn the speed 'pot' way down to a slow rpm but not to zero. My old General 260 has a "Forward/Stop/Reverse" switch which I use while turning. At the end of the day I turn the speed down --- hit the red power off button (mounted on the inverter box) --- and then pull the plug from the wall. I do this in case there is a power surge or lightning strike that would fry my inverter or mess it up. Some of you may think this is overkill.....but I think of it as an insurance policy! Had the lathe for 24 years without any inverter problems.

 

[Gary Beasley]

Nova recommends installing surge protection on the incoming power, I put a whole house surge protector in the switch box. Hopefully this will ward of all but the worst incidents. Surges are a very real problem from storms and solar activity.

 

[Karl Loeblein]

I have trained myself to turn the lathe speed to zero before hitting the switch. I have also got into the habit of flipping the breaker off when not using for more than a few minutes. The box is right behind the head stock so easy to hit.

John,
Flipping the breaker off doesn't disconnect the neutral or ground wire in case of an electrical storm. It is safest to unplug your lathe when finished for the day. I heard of VFDs getting fried even when the breaker was off so I don't take a chance because it only takes a few seconds to unplug most lathes.

 

[John Walls]

Thanks for the hint. At the moment, mine is hard wired to the box, no plug. When I get a chance this summer and make it to the hardware store I may put a plug end on to be safe.

 

[Don Wattenhofer]

The VFD's used on most lathes have accell, decel and minimum & maximum speed settings although many of the lathe manufactures apparently don't think turners should be able to access the settings. The VFD's on my lathes are units that I bought and installed myself and I set the accel, decel and the minimum and maximum speed as I like. My practice is to just hit the stop button or switch then when I am done for the day I hit the power switch. As far as starting at a high speed setting I have taught myself to turn the speed down to minimum when dealing with heavy out of balance turnings, but when working on turnings that are already balanced I leave the speed pot alone.

 

[Bill Boehme]

I have also got into the habit of flipping the breaker off when not using for more than a few minutes.

Circuit breakers aren't meant to be used as switches. Frequent toggling can lead to a breaker becoming "weak" ... meaning that they will trip at a much lower current than its rated current.