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Other Safeties Use them or Not?
- Thread starter Former Member
- Start date
Former Member
Guest
Safeties/stop are always series.
Starts are always parallel.
Easiest way is through a latching relay with the power off position as off. Any fault in its off.
In CNC is set up this way.
Starts are always parallel.
Easiest way is through a latching relay with the power off position as off. Any fault in its off.
In CNC is set up this way.
Dabbler
ersatz engineer
I'm sure you are familiar with how e-stop wiring is done industrially. However, many newbies here may not.
All safety stops are NC wired in series, such that all power to the lathe is disconnected, usually in the main contactor loop. This gives the best chance of the estop doing the right thing even in a malfunction.
Doggggboy
Ultra Member
Yes.
There is no lockout switch.
The FWD/REV switch is in a convenient place to use, and if I replace with buttons I'd try to put them in a similar position, it's just that it is easy to bump the lever with an elbow while fiddling with the belt during a change.
It would be harder to depress a button or turn a knob by accident.
140mower
Don
You could put a magnetic starter between the lathe and power supply. As an added bonus if the power is disrupted for any reason the lathe won't restart when the power is restored. Both my lathes are wired this way, some, maybe even most have a huge stop button for when urgency outweighs accuracy.....
SNIP!
@Brent H speaks the truth!
I've never used a lathe with a chuck cover, is the motivation to keep you from turning the machine on with the key in place or to keep fingers out of rotating pieces or ? Probably for keeping fingers out, I guess those of us without guards will have to be aware enough to keep our fingers out of places they shouldn't be like we were taught as a kid!
My table saw came with a poorly made, flimsy guard with a bunch of fiddly stamped pawls and jaws that interfered with the machine being used and was in itself dangerous because it invited extra hands-on in the danger area to finagle it to get it to work so it gathers dust. It's replaced above all by discipline - asking myself: "how could this be dangerous?" and using handling aids like the nice plastic push sticks BB sells.
For background, I was taught young. My grandfather was a fishing boat builder (Cape Islanders) and he showed me the end of a sawmill building where a log was thrown through the wall after getting caught in the blade as a warning of the consequences of things being thrown by a saw. He also showed what his 10 HP gas powered circular saw (no safety shut off) could do with a small stick just to drive home the point. Keep your lumber under control and stay out of the line of fire! It's your responsibility!
I recently saw an ad for a chip guard for the typical BP/Clone mill which, along with the discussion here about shower curtains etc. to retain chips has me pondering how to come up with something that will keep the chips from flying everywhere including your face. I think that would be a good addition if it's not too big a hindrance and doesn't cost $1000 like the one I saw! I also thought about this yesterday as I watched the mill on power X feed and reminded myself the only place my hands should be are on the power feed control or in my pocket.
I put an E-STOP on my lathe when I was wiring it up. It's not a full bore E-STOP, it disconnects the machine from the mains so no matter what you do with the FWD/REV switch nothing happens. As others have said, that would give you, @Doggggboy some more peace of mind and by human nature be more likely to be used than unplugging. There's a photo in my Intro Posting: Tecnico's Intro Posting, you could just add a box in the power cable before the lathe.
I had been exposed to E-STOPs and the discipline in process equipment in my day job. It's a good addition especially if you build the discipline to hit the button when you will have your fingers in the works where you could be injured, say, if the FWD/REV switch gets bumped. Mine also get used for material/chuck changes etc. and at the end of the job/day etc. so the default when you walk up to the machine is you know is it is inactive and safe. Keeps curious visitors from starting the machine too.
I also have a long term plan to put one on my mill however it is electrically more complicated than the lathe. It still gets turned off at the power box for belt changes and the plug pulled at the end of the day - I'll leave the discussion at that for now while I think about how to do an economical relay E-STOP.
Speaking of E-STOPs, what I described above in my lathe is not really a true E-STOP, it's more like a secondary safety switch. I'm not certain of exact details but according to standards like CSA Z432-14, E-STOP is stopping a machine as quickly as possible without creating additional hazards when triggered. There's a set of guidelines for implementation.
I don't know what a laser enclosure like @David_R8 's has (not picking on you, David) but it's a great candidate for a passive, latched E-STOP on the lid to prevent access while it's active. Latched here means it doesn't automatically close the switch when you close the lid, it needs you to intentionally close a relay with a separate switch to activate the circuit. To me that’s a no-brainer.
Apart from any regulatory imposed safeties (common sense or not, it's driven by the law) all of these machines we use still require you to think before doing and that isn't always the embedded discipline. Common sense stuff like @Dabbler said, no gloves or what someone else said, no loose clothing - my father taught and he wore a clip-on tie in the shop. Keep your fingers out of the machinery when it's running and so on.
OK, enough for now! Good discussion tonight.
D
Last edited:
Exactly, the E-STOP switch operators are push to stop, twist to re-activate so it's less likely to be re-set unintentionally.
D
Former Member
Guest
Here is a safety that did its job. But at the same token there are issues that are not addressed just in set up alone.
I think this is an example of how safeties are breeding a new form of complacency in the user.
I think this is an example of how safeties are breeding a new form of complacency in the user.
He broke the rule of stop the machine before sticking your finger close to the moving parts.
I remember in shop class in jr high having to stand beside the bench grinder until it had come to a stop and was therefore safe to walk away from.
D
There's no safety on my enclosure, only the userSNIP!
@Brent H speaks the truth!
I've never used a lathe with a chuck cover, is the motivation to keep you from turning the machine on with the key in place or to keep fingers out of rotating pieces or ? Probably for keeping fingers out, I guess those of us without guards will have to be aware enough to keep our fingers out of places they shouldn't be like we were taught as a kid!
My table saw came with a poorly made, flimsy guard with a bunch of fiddly stamped pawls and jaws that interfered with the machine being used and was in itself dangerous because it invited extra hands-on in the danger area to finagle it to get it to work so it gathers dust. It's replaced above all by discipline - asking myself: "how could this be dangerous?" and using handling aids like the nice plastic push sticks BB sells.
For background, I was taught young. My grandfather was a fishing boat builder (Cape Islanders) and he showed me the end of a sawmill building where a log was thrown through the wall after getting caught in the blade as a warning of the consequences of things being thrown by a saw. He also showed what his 10 HP gas powered circular saw (no safety shut off) could do with a small stick just to drive home the point. Keep your lumber under control and stay out of the line of fire! It's your responsibility!
I recently saw an ad for a chip guard for the typical BP/Clone mill which, along with the discussion here about shower curtains etc. to retain chips has me pondering how to come up with something that will keep the chips from flying everywhere including your face. I think that would be a good addition if it's not too big a hindrance and doesn't cost $1000 like the one I saw! I also thought about this yesterday as I watched the mill on power X feed and reminded myself the only place my hands should be are on the power feed control or in my pocket.
I put an E-STOP on my lathe when I was wiring it up. It's not a full bore E-STOP, it disconnects the machine from the mains so no matter what you do with the FWD/REV switch nothing happens. As others have said, that would give you, @Doggggboy some more peace of mind and by human nature be more likely to be used than unplugging. There's a photo in my Intro Posting: Tecnico's Intro Posting, you could just add a box in the power cable before the lathe.
I had been exposed to E-STOPs and the discipline in process equipment in my day job. It's a good addition especially if you build the discipline to hit the button when you will have your fingers in the works where you could be injured, say, if the FWD/REV switch gets bumped. Mine also get used for material/chuck changes etc. and at the end of the job/day etc. so the default when you walk up to the machine is you know is it is inactive and safe. Keeps curious visitors from starting the machine too.
I also have a long term plan to put one on my mill however it is electrically more complicated than the lathe. It still gets turned off at the power box for belt changes and the plug pulled at the end of the day - I'll leave the discussion at that for now while I think about how to do an economical relay E-STOP.
Speaking of E-STOPs, what I described above in my lathe is not really a true E-STOP, it's more like a secondary safety switch. I'm not certain of exact details but according to standards like CSA Z432-14, E-STOP is stopping a machine as quickly as possible without creating additional hazards when triggered. There's a set of guidelines for implementation.
I don't know what a laser enclosure like @David_R8 's has (not picking on you, David) but it's a great candidate for a passive, latched E-STOP on the lid to prevent access while it's active. Latched here means it doesn't automatically close the switch when you close the lid, it needs you to intentionally close a relay with a separate switch to activate the circuit. To me that’s a no-brainer.
Apart from any regulatory imposed safeties (common sense or not, it's driven by the law) all of these machines we use still require you to think before doing and that isn't always the embedded discipline. Common sense stuff like @Dabbler said, no gloves or what someone else said, no loose clothing - my father taught and he wore a clip-on tie in the shop. Keep your fingers out of the machinery when it's running and so on.
OK, enough for now! Good discussion tonight.
D
Former Member
Guest
Darwin safeties.
Be safe or get taken out of the gene pool.
Be safe or get taken out of the gene pool.
Unless my bride let's me sew a few more wild oats, I've already done my bit & left the gene pool competition 30 years ago.
But that does not mean anybody gets to pull my plug without a really nasty fight.
Tom Kitta
Ultra Member
I know little off topic but sometimes too much safety or too much emphasis on useless "safety" is too much. I.e. one should concentrate on safety that is causing most accidents - what is the most likely to kill or injure you, not on safety that is appearing to be important or make you a safety nut.
Off topic example:
Long time ago I setup top rope for rock climbing. I had a guy with me that was super safety conscious. We are talking ... safety guy. So I made the setup and went down while he inspected few girls above. Our guy checked like everything - my setup other setups... except where the girl that was coming down clipped her rope.... instead of the strong belay loop she was clipped to her gear loop - a loop that is used to hold climbing gear to the harness - just a piece of plastic.
As she was coming down to me I saw it... my eyes got a bit wide and in the most calm voice possible I told her to go down as smooth as silk... she was skinny and made it alive.
In his safety check he missed the most important aspect...
So if I had any of these chuck guards I would remove them as especially on the drill press I find it hard to have stuff fall into spinning chuck. A lot of other safety through is quite essential - just don't over do stuff or have too much of it.
Off topic example:
Long time ago I setup top rope for rock climbing. I had a guy with me that was super safety conscious. We are talking ... safety guy. So I made the setup and went down while he inspected few girls above. Our guy checked like everything - my setup other setups... except where the girl that was coming down clipped her rope.... instead of the strong belay loop she was clipped to her gear loop - a loop that is used to hold climbing gear to the harness - just a piece of plastic.
As she was coming down to me I saw it... my eyes got a bit wide and in the most calm voice possible I told her to go down as smooth as silk... she was skinny and made it alive.
In his safety check he missed the most important aspect...
So if I had any of these chuck guards I would remove them as especially on the drill press I find it hard to have stuff fall into spinning chuck. A lot of other safety through is quite essential - just don't over do stuff or have too much of it.
Tom O
Ultra Member
Here’s the latest one from Doubleboost
I was lifting a box from a high shelf.
It all came crashing down , I fell backwards .
Once i had regained my feet I had a 2.4 mill tungsten sticking in to my wrist .
It had a good hold and would not come out.
Straight in at A&E
Could not operate as i had eaten.
They kept me in overnight with my arm suspended above me .
I had 3 10ml doses of IV Morphine and still never slept.
They did a nerve block on my arm it was totally numb.
I watched the Surgeon slowly work his way in then pull it out.
I told him that I had tried . He pointed out to me that if i had nicked the artery I would have had 3 minutes
The medical care I recived was amazing
I was lifting a box from a high shelf.
It all came crashing down , I fell backwards .
Once i had regained my feet I had a 2.4 mill tungsten sticking in to my wrist .
It had a good hold and would not come out.
Straight in at A&E
Could not operate as i had eaten.
They kept me in overnight with my arm suspended above me .
I had 3 10ml doses of IV Morphine and still never slept.
They did a nerve block on my arm it was totally numb.
I watched the Surgeon slowly work his way in then pull it out.
I told him that I had tried . He pointed out to me that if i had nicked the artery I would have had 3 minutes
The medical care I recived was amazing
Former Member
Guest
Safeties have their place, and most of them would have done not a thing for the Tungsten injury above (Ouch!!) I figure it's best to learn early that among other things, Mother Nature isn't very motherly, and safeties will not keep you safe all the time. Sometimes minor bloodshed, teaches lessons that would have been much worse, if not learned with a little discomfort!
I spent a year+ in a Aviation related Technical college in Quebec, and the lathes all had multiple E-Stop buttons around them at the operators position, as well as at both the head and tail stock ends, so it did not matter which way you dove, you could slap one on the way by, or an Instructor could. These were in addition to the foot brake/shutoff pedal that ran most of the length of the toe space in front of the lathes.
I particularly hate the chuck shields, wired in to the electronics, as they can be useful, or a disaster waiting for the crash noise. When they are convenient to use for such, they are great for keeping the coolant spray contained. When not, they are just...not. Would much rather have the chuck guard set up so you could slide it in and out (along the Z axis), as well as flip it right out of the way, and it would actually be useful sometimes.
I ran a knee type CNC mill for a long while, and made up my own shields for use when the coolant and chips were flying a bit much. Really simple. A more or less, 90 degree bend, in two pieces of sheet metal, so they would sit easily around the work, and were well able to be knocked out of the way at no real risk, if they must. I had Aluminum sheet, so used that, but Plexiglass or acrylic would work too. Just a spray shield, to keep the junk on the table.
I spent a year+ in a Aviation related Technical college in Quebec, and the lathes all had multiple E-Stop buttons around them at the operators position, as well as at both the head and tail stock ends, so it did not matter which way you dove, you could slap one on the way by, or an Instructor could. These were in addition to the foot brake/shutoff pedal that ran most of the length of the toe space in front of the lathes.
I particularly hate the chuck shields, wired in to the electronics, as they can be useful, or a disaster waiting for the crash noise. When they are convenient to use for such, they are great for keeping the coolant spray contained. When not, they are just...not. Would much rather have the chuck guard set up so you could slide it in and out (along the Z axis), as well as flip it right out of the way, and it would actually be useful sometimes.
I ran a knee type CNC mill for a long while, and made up my own shields for use when the coolant and chips were flying a bit much. Really simple. A more or less, 90 degree bend, in two pieces of sheet metal, so they would sit easily around the work, and were well able to be knocked out of the way at no real risk, if they must. I had Aluminum sheet, so used that, but Plexiglass or acrylic would work too. Just a spray shield, to keep the junk on the table.
Yeah, safety shields.
In my home shop I have eStops everywhere but no shields. At the University I insist on stops & shields on everything. Here's why:
Years ago I watched an associate killed by a lathe.
He reached for the stop switch which was located above the headstock. Some clothing caught on the exposed chuck jaws. His arm was pulled under the chuck and severed.
A moment of inattention could have been prevented by a guard.
Nuff said.
In my home shop I have eStops everywhere but no shields. At the University I insist on stops & shields on everything. Here's why:
Years ago I watched an associate killed by a lathe.
He reached for the stop switch which was located above the headstock. Some clothing caught on the exposed chuck jaws. His arm was pulled under the chuck and severed.
A moment of inattention could have been prevented by a guard.
Nuff said.
That could have been FAR easier prevented by a Stop Switch that was not located above the chuck too!
Doesn't matter how many "Safety Features" the machine has, if the are as badly implemented as that seem to have been!
As to that moment of inattention that could have been prevented, so far, all the lathes I used that had chuck guards, had no means whatsoever, to prevent you from sticking an arm UNDER the chuck, or chuck guard! Most stopped at about the horizontal line, across the chuck.
The were mainly an annoyance that stopped the chuck from turning, if the cover was not pulled fully closed.
Former Member
Guest
I had a yellow line painted on my 3 jaw chuck the was easy to see and gave warning to the snag points (jaws) . It help develop safer habits because you always saw the line (though you couldn't see the jaws) and that reminded you that there are jaws there, which helped when I first started out.