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Guys, I've figured something out!

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Pcmaker

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#1
I just had an idea... lemme know if it's any good or not.

I'm new to this hobby. I ordered my lathe, but I haven't received it yet. Hopefully I'll have it by Tuesday, so I dunno if this has been tried before or not.

I"ve been watching a ton of lathe how-to videos on Youtube and there's one recurring theme about safety. Never leave the chuck key on the chuck. The plastic guard is a good idea.. preventing the operation of the machine if the key is still on the chuck.

My idea is.. why not install a key switch on the machine with the switch key machined/welded on the chuck key? Put a key switch on the machine that you can't pull out while the lathe is in operation.

Wire the main hot wire coming into the key switch, then the outgoing wire to wherever the original hot wire goes to.

Install the key switch to where it's not in the way. Sorry for the poor photoshopping skills.

The power to the machine will not operate without the key in the switch and there will be no power to the machine if the chuck key isn't inside the switch.



 

Chuck K

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#2
Thats a great fix. I made the mistake of leaving the key in the chuck early on...not something I would suggest. It's also one of those things that once done, left a lasting impression on me. I've caught myself removing them from other peoples machines when I see them left on their chuck.
 

David S

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#3
For sure that will work. There have been similar solutions over the years. Some are to make a holder with a microswitch such that the switch won't be closed unless the chuck key is placed into the holder.

My friends Craftex lathe has a spring loaded key that you have to press down into the chuck to engage and turn overcoming a spring return. Release pressure on the key and it pops out of the chuck.

David
 

gaston

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#4
Learn good work habits and its a non issue. I have a holder on my lathes for the chuck key and when ever I use it . Back in the holder it goes.
Been useing lathes for over 40 years and have never thrown a chuck key
 

DAT510

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#5
As other have mentioned good habits go a long way.

At one company I was at, the "safety" department had the equipment engineering group design a "Chuck Key Holder / Interlock Switch", which prevented the lathe from turning on without the chuck key in the hole. It was nice in the fact it was non intrusive to good habits. Take the chuck key out, put in the holder, machine runs, no other steps, other than putting the key away.
 

T Bredehoft

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#6
You've never misplaced a chuck key!
 

P. Waller

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#7
It is far safer if you never connect a machine to a power supply, at one time I had an old South Bend lathe that sat in a corner of the building for 15+ years, it was never connected to the grid and was the safest machine in the shop without question.
 

stuartw

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#8
my .2c is, that's an ok solution if you only have one chuck. What happens when you acquire more than one chuck? each requiring a different key? :)

Some lathes have a shroud connected to a switch that can only fit in place if there's no key in the chuck. But ... safety systems only work if you're willing to be disciplined! if people want to be lazy unsafe, they seem to always find a way.

ps. your lathe is probably coming with a 3 jaw chuck, you may want to at least get an independent 4 jaw check as well.
 

GL

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#9
The intent is good, execution may have issues. As previously mentioned, you may have more than one chuck. A key attached to a chuck key may be easily broken off or like too many car keys on a ring, the switch has issues over time. The holder with switch has merit. Just doing it right is the best. Easier to enforce the rules when they are yours.
 

4ssss

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#10
Why is it so hard to remember to take the chuck WRENCH out of the chuck? And why is the chuck KEY also so hard to remember to take out of the Drill chuck?
 

rwm

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#11
What I have found is that if you make it really easy to store the chuck wrench in a safe place you will get into the habit and do it consistently.
Hence:



It is so easy to drop the wrench into the tapered Delrin lined hole that I do it very reliably. When I switch chucks the old key goes with the chuck and the new key goes in the holder. No electrical wiring necessary.

Robert
 

stuartw

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#12
Why is it so hard to remember to take the chuck WRENCH out of the chuck? And why is the chuck KEY also so hard to remember to take out of the Drill chuck?
hard to say, but enough people have forgotten both hobbyist and professionals that there's a lot of attention paid to it.
 

rock_breaker

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#13
Why is it so hard to remember to take the chuck WRENCH out of the chuck? And why is the chuck KEY also so hard to remember to take out of the Drill chuck?
My experience is that I am thinking of the next step in the project when I let loose of the chuck wrench as the work is grasped by the other hand. Hard habit to break but fortunately I notice the error right away.
have a good day
Ray
 

Bob Korves

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#14
If you simply do not allow yourself to take your hand off the chuck wrench when it is engaged in the chuck, the problem is solved without gadgets. If it fails, you know you disobeyed your own rule.
 

petcnc

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#15
When I bought my mini lathe the chuck key had a spring that did not allow it to remain in the chuck unattended.
It helped me to develop the habit of removing it always. This habit remains now after changing the chuck for a bigger one and a key without a spring.
 

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tjb

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#16
Just barely into my machining rookie phase, I acquired an old Harrison M300 lathe (1979 model) for a practically junk-metal price. I had a very educational experience returning it to a good usable condition. Learned a lot about how a lathe works, 3-phase wiring and general machine maintenance. Being nearly 40 years old, the M300 had fewer safety devices on it than my newer lathe - one of which was a chuck guard. It was obvious to me that being commensurately a rookie and a senior citizen was very likely a formula for disaster since I had never been exposed to some of the subconscious safety factors many long-termers knew innately. Flying chuck wrenches can be deadly I am told. I decided to fabricate a chuck guard, loosely modeled after the one on my newer lathe. Not pretty, but it gets the job done:

IMG_1274.JPG

Learned a little more about 3-phase wiring and gained some experience in bending sheet metal as well. But the best part is I figured out a way to protect myself from myself. One thing I've learned over the years about safety (sometimes the hard way): Do the best you can to 'anticipate' a catastrophe; then take the time to design steps to eliminate it.

Regards,
Terry
 

higgite

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#17
I’m not saying abandon your idea, but will suggest developing a habit that will make it redundant while serving 2 important purposes. That is turning the chuck by hand every time after you set up a work piece in the chuck or alter its set up. First purpose is to verify that there is no interference between the chuck or the work piece and the lathe bed, carriage, cross slide, compound or whatever before you hit the go button. Second, if you leave the chuck key/wrench/t-shaped thingy/whatever you want to call it in the chuck, you will notice it immediately when you jam your hand into it when you reach in to turn the chuck.

Tom
 

Cadillac

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#18
I would think that putting all them extra safety switches would make me not wanna me to use the machine as much. I’ve never had a incident but who’s to say it can’t happen. The only time I would leave the key in is when I remove a part and am done for the day. I do have a chuck cover that will not allow the key to be in when guard is down.
If you don’t trust yourself you can easily make you chuck key spring loaded. Drill a hole in center of chuck key About 2” deep. Then slot hole to accept a roll pin the width of flats on key. Make a pin the same diameter about 1 1/2” long. Drill a hole to accept roll pin. Put a spring in chuck key hole then pin. Lock pin with a roll pin the width of flats on key. You should have a ejector pin on end of key that will eject when not in use. Done nice little project. :)
 

chips&more

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#19
Like many have said. Just learn good work habits. I have never thrown a chuck key. My chuck keys do not have that annoying spring! Or any other thing a ma gig to prevent a thrown key. It’s just a simple golden rule “don’t leave the chuck key in the chuck”…Dave
 

FOMOGO

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#20
That much weight on your key, won't be kind to your switch. Mike
 

PT Doc

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#21
Jet tools has a some type of duck key docking port that removes power to the machine unless the key is in the dock. It’s on their larger machines in case you want to look at them I think the 14x40 machines.
 

Charles Spencer

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#22
You've never misplaced a chuck key!
Nope, never. Actually I have a drawer just for lathe and drill chuck keys and I buy more of them whenever they come up for sale cheap. When I change chucks I return the old key to the drawer and take out the new one. I may have lost one or two along the way but I'll never confess to it. My drill press has the key tied to it by a string.
 

Bi11Hudson

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#23
Quoting:
I’m not saying abandon your idea, but will suggest developing a habit that will make it redundant while serving 2 important purposes. That is turning the chuck by hand every time after you set up a work piece in the chuck or alter its set up. First purpose is to verify that there is no interference between the chuck or the work piece and the lathe bed, carriage, cross slide, compound or whatever before you hit the go button. Second, if you leave the chuck key/wrench/t-shaped thingy/whatever you want to call it in the chuck, you will notice it immediately when you jam your hand into it when you reach in to turn the chuck.

A good practice there, for several practical reasons.... Way back when I was in EM (electrician, 1968) school, there was a practice in the mechanical school where machining was taught. If a student was seen leaving a key in the chuck, lathe, drill press, whatever, he had to wear a very large (and heavy) lathe chuck key on a lanyard for 24 hours. That cured most of the memory problems. Especially during meals....

In my case, having several chucks of varying types and sizes, the same quote from above applies. When the chuck near misses one time, it usually is enough. My machine is very old (older 'n me) and has few safeties beyond what I have put on it. The big issue is an odd shaped workpiece loaded. I always try it by hand first, by habit now.

The key is a good idea for locking out any/all machines, long term. But I would be skeptical of such a weight on the key. The switch wouldn't last long, even if the key did.
Bill Hudson​
 

Cadillac

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#24
As for weight of key breaking switch. Use a magnetic pickup switch. When it sense the chuck key it closes the circuit. Like door and window switches for alarms. Sink it in the hole you would store the key “NEAR” the chuck.
 

NortonDommi

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#25
Having had my ears clipped hard if I ever had a key in the chuck without my hand on it I have a phobia about this subject! As has been mentioned good work habits are life savers. Make a holder/s and use them. I've developed a habit of putting the lathe in neutral and hitting the Emergency Stop switch whenever my hands go near the chuck, one it makes it easy to turn and two if I bumped the control rod nothing happens.
Good work habits and fear will keep you safe.
 

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Silverbullet

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#26
Positively the key will break in the switch from the chuck key , weight or accidentally. Better off with a deadman switch like a limit switch to hang the chuck key on.
 

jrkorman

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#27
Learn good work habits and its a non issue. I have a holder on my lathes for the chuck key and when ever I use it . Back in the holder it goes.
Been useing lathes for over 40 years and have never thrown a chuck key
Maybe so, but I remember Dad always taped the chuck key about 6 inches from the plug. You couldn't use the key when pluged in. Added feature - makes it hard to loose a chuck key!
 
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