The thought that immediately jumped to mind when I read the subject line was 'out of the line of fire!'
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The thought that immediately jumped to mind when I read the subject line was 'out of the line of fire!'
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You got to be kidding me, Green is on, Red if off. All the time.
Contributor
Originally Posted by William Bachtel
Actually, I don't think the OP was kidding. Some lathes have more options than others.
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Even vfds are rated for number of starts and stops over a period of time. its what you have to do I guess. I have out fitted one newly built lathe with an air operated clutch and break and a lever control for the valve. two other lathes have rolling grip clutches on them and as often as possible I dont turn the lathe off. I know there is a difference between an artist wood turner and a production wood turner. The op didn't specify though and the best thing for a motor to stop and start is not to.https://i.ytimg.com/vi/P12E08byJ6k/mqdefault.jpg
Right, some folks are answering without understanding the question/situation. I admit to having done this myself a time or two when in a hurry and it will probably happen again. I apologize in advance. While the manual states that the variable speed is to be all the way in the counterclockwise position before hitting the start button, it does completely miss the "stopping to check you work" activity common while turning. I think Geoff W pretty well has you covered on the ins-and-outs of VS drives.
"A hen is only an egg's way of making another egg".
– Samuel Butler
Contributor
I stop peddling . . . your lathe might be different.
Bill
Member
My lathe is an older one without a lot of electronic controls. It has a red button and a green button. When you want to turn it on you push the green button. When you want to turn it off, you push the red one. It's kind of like a traffic signal. Red...stop. Green... go. "Unintended startups from disturbance of controls" is not really an issue since the two buttons are not in a position where one might unintentionally activate them. Plus, there are little bezels around the buttons that would prevent unintentionally pressing them. "Inadvertent selection of the “wrong” lathe rotation direction" is not an issue either as the lathe only turns in one direction. As long as you can remember which direction it turns, you're fine. There is also a speed control for the often denigrated Reeves drive. As we all know, electronics never fail like the old fashioned mechanical systems do and even if they do get messed up, all you need is a degree in electronic engineering and computer programming to get it up and running again. And we all know that every turner worth his salt possesses both of those. Those old mechanical systems? Well be prepared to get into some serious, highly technical processes like tightening a set screw! And the risks? Well, it's nothing as benign as getting electrocuted, let me tell you. We're talking potential for major bodily harm here... skinned knuckles, broken fingernails... you name it. If you'tre gonna take on something like that you better call 911 before you even start just to be sure they can make it in time!
David DeCristoforo
Member
David you make some very good points about mechanical lathes - they give you a little more time to think about what you are doing when changing speeds, and sure they have less hazards (economic as well) when compared to EVS lathes.
I have a Vicmarc VL150 which has the controls just below the head stock similar to many other lathe designs. While doing small spindle work I tend to brush my left hip against the lathe cabinet which contacts the dial & fortunately so far has only rotated the VS pot to slow speeds. Doing bowls this is not a problem as I don't get my body into that position unless turning inside & outside profiles from the one mounting. On the latest VL150's Vicmarc has relocated the VS pot on the control panel which reduces this particular hazard.
I've seen a little more than "skinned knuckles, broken fingernails" happen to "turners who should know better." If you ever get to collaboration / participation style events it is interesting to watch some of the logic process that turners use to create their turnings & to do emergency lathe maintenance. Only a few weeks ago I watched a couple of very experienced turners pulling a small mini lathe apart to replace a broken belt - all with the lathe still connected to power and many helpful advisers offering technical advice! I'm sure in your shop you would not approve of your employees doing that.
Belt Replacement - "1. Disconnect the machine from the power source (unplug)." Pretty basic rule but they didn't do it!
It would not be a pretty picture to see the results of what the VS speed pickup / encoder would do to fingers if the lathe was accidently turned on - but in this case that wasn't a hazard because there was no belt on the lathe.
Last edited by Geoff Whaling; 11-15-2015 at 4:06 PM.
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Came across someone's video today. Again, this is why I always use the speed control. If done using, then power is killed also. Plug pulled if leaving shop (to protect electronics)
https://youtu.be/5y1wGm-ePi4?t=1657
Member
Me too!
Thank you for the link a valuable teaching aid. It helps to illustrate the value of the OP’s question and the potential consequences of not adopting a “safe” process. Fortunately it was a near miss. Others have not been so lucky.
Quite impressive to see how much the lathe bed and stand flexes, how the tail stock quill rotates, all caused by the dynamic balance issues resulting from unintended / incorrect speed selection.
The slow motion replay demonstrates the hazards of a very common woodturning scenario and how not using recommended safe operating procedures (controls) can very quickly escalate into a potentially dangerous event. It helps to dispel a few myths about the security of turning between centres. It’s only secure if you follow the process.
Safety is a relative concept!
The methods used to make a process “safe” will vary due to lathe design & construction, EVS/belt change/reeves drive, even position of controls, the size & condition of the project blank, available tools, operator knowledge / experience etc. What is safe for one turner/project/scenario may be unsafe for others - but using a check process is a universal safety protocol and some processes will universally produce desired outcomes.
Adopting simple check processes reduces and ideally eliminates some hazards & therefore risk.
Potentially dangerous events (near misses) in woodturning are usually (always?) the result of a combination of several hazards, some of which are known, some unknown, unforeseen, some are simply oversights and / or a lack of knowledge / experience by the operator – part of the learning process. We all have forgotten to reduce lathe speed at some time in our turning careers.
However one or two “small” oversights may bring other more dangerous hazards / factors into play.
Running through a conscious process / routine to both start & stop the lathe can eliminate/reduce some of the potential hazards and pick up a few omissions like forgetting to reduce lathe speed, or lock the tailstock quill, remembering to stand out of “the line of fire” etc.
It costs only a few seconds of your time to adopt a check process - put on personal protective equipment (face shield etc), start lathe speed slow then increase speed, stop & recheck blank mount security, etc. Then following a process to dial, change belts, or reves drive selector back to a slow speed setting at the end of a session, isolate lathe at end of day etc all help to reduce risk.
A check list doesn’t have to be elaborate like a pilot’s flip chart but it may help beginners to document the checklist & doesn’t hurt old hands to review what they do once in a while.
http:// www .woodworkforums. com/showthread.php?t=164022 (copy & remove spaces as directed by Steve – thank you for leaving the edited link)
Last edited by Geoff Whaling; 11-16-2015 at 3:43 PM.
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