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Posted: Sat May 08, 2010 10:46 pm
by inonickname
No need for the spring. Everyone should really practice "never let go of the chuck key while it's in the chuck".
Posted: Sat May 08, 2010 11:23 pm
by maverik94
No need for the spring. Everyone should really practice "never let go of the chuck key while it's in the chuck".
True, prevention is the greatest remedy, but when you're really forgetful like me, it really helps

Posted: Sun May 09, 2010 1:04 am
by Moonbogg
Looks real to me. Very shocking and it drives fear right through me. Oh, and you would NOT have even a split second to react to turn off the machine. If you get caught, you are screwed instantly. Good God, I can do without a lathe for sure.
Posted: Sun May 09, 2010 2:41 am
by Crna Legija
the lathe we have at tafe has a dead mans switch but i doubt that it would do anything when its spinning at full speed the momentum will still get you
Posted: Sun May 09, 2010 5:51 am
by Insomniac
-_- wrote:the lathe we have at tafe has a dead mans switch but i doubt that it would do anything when its spinning at full speed the momentum will still get you
That's why it's called a 'dead man's switch' and not a 'somewhat injured man's switch'
Posted: Sun May 09, 2010 10:39 am
by mark.f
Well, I've had an accident with a drill press that resulted in a gigantic bruise on my arm. I'll let you guys guess how I did that.

Dead man switch
Posted: Sun May 09, 2010 10:49 am
by Technician1002
The dead man switch on a lathe works well when coupled to an electric (DC on AC motor) brake. Due to the cutting speed of most metal, the larger the swing, the slower the RPM. Cutting speed is a function of the rate the tool travels on the surface of the metal. Much like a CD in a player, the RPM is high near the center and low near the edge. If you use a higher power lathe, look into an electric brake for the induction motor.
A key switch is highly recommended so the lathe can not be started with the key in the chuck.
Most operators do not like to use a foot operated dead man switch as it requires a static operator postion so it is often located in the wrong place for viewing inside cuts and inside threading of parts. I think most lathes should have a "Pull Cord" running the length of the lathe a short distance above the work so if anything gets pulled in, it will pull the cord. It should be low enough so an accidentally left in chuck key will catch it and pull it. This is my 2 cents worth on a dead man switch. Many small lathes have a guard, but they are hard to keep clean as cutting oil and thrown hot chips mar the surface.
Due to damage to the guard, these are often removed.
Edit @ Mark, Left in the chuck key and turned it on.. Hmmm? Seen it happen too many times. I wish more drill presses were equipped with a chuck key switch. If the key is not put in the holder, the press power is cut off. I think a switched chuck key holder should be required on all drill presses for that very reason.
My Harbor Freight dirll press has a weaker solution. The key has a spring loaded pin in the end so it can't stay in the chuck. It spits itself out. That will only work until the key is lost and a replacement key without the spring pin is used. The drill press needs a designated key holder. Hopefully with a safety switch on it.
On the subject of safety devices blocking the view, my largest complaint is with table saws. Common practice it to cover the blade area with a plastic guard that quickly gets a static charge and covered with sawdust. I finally saw a table saw with a guard that worked. the guard was simply a metal ring made from 1/4 inch metal rod. This guard simply laid on top of the wood being cut. It did not go over the blade at all but simply surrounded the danger zone. Most fingers are cut while guiding wood into the blade. Having a metal rod in front of the balde and alongside both sides of the blade prevents fingers from approaching too close. It did not block the view, but was very effective in blocking fingers guiding wood.
In regards to the table saw, the shop prohibited long sleeves and gloves near the power tools. Gloves and spinning blades do not mix. Loose clothing and power tools do not mix.
Posted: Sun May 09, 2010 10:58 am
by maverik94
That's why it's called a 'dead man's switch' and not a 'somewhat injured man's switch'
Lol, nice.
Posted: Thu May 13, 2010 3:45 pm
by Lentamentalisk
"Shopped!"
[/tasteless humor]
Posted: Thu May 13, 2010 4:58 pm
by mark.f
Technician1002 wrote:Edit @ Mark, Left in the chuck key and turned it on.. Hmmm?
Nope. The bruise involved an implement much larger than a chuck key (the bruise was baseball-sized).
Posted: Thu May 13, 2010 5:18 pm
by Demon
Was it because you drilled something, then, as the drill bit was stuck in the workpiece, you un-clamped it and accidently turned the drill press on making the workpiece spin?
Posted: Thu May 13, 2010 5:35 pm
by pizlo
Does anyone else not think this link should be on a site that kids come to? I know I came here when I was 12 and I sure as hell wouldn't want a 12 year old to click that link...
take it down please?
Posted: Thu May 13, 2010 5:38 pm
by Zoltar9879
Was it because you drilled something, then, as the drill bit was stuck in the workpiece, you un-clamped it and accidently turned the drill press on making the workpiece spin?
I've done that. (I should have remembered to clamp the piece down BEFORE starting the drill

) I've never made that mistake again.

Posted: Thu May 13, 2010 6:03 pm
by MrCrowley
pizlo wrote:Does anyone else not think this link should be on a site that kids come to? I know I came here when I was 12 and I sure as hell wouldn't want a 12 year old to click that link...
take it down please?
Personally I don't mind it being up as long as it has a warning and no pictures are linked directly (so they show up straight away). It is sort of educational and it's not like a 12 year old couldn't find something similar on the internet if they tried. If they truely are an innocent 12 year old who doesn't like this stuff, the warning is in place.
Other mods might have a different opinion and if they want to remove it, I wont object.
Posted: Thu May 13, 2010 7:16 pm
by mark.f
Demon wrote:Was it because you drilled something, then, as the drill bit was stuck in the workpiece, you un-clamped it and accidently turned the drill press on making the workpiece spin?
You're getting warmer, but your hypothesis is based on the assumption that I actually took the time or had the money to clamp the workpiece with an actual vise.
I guess I'll just say it. I was drilling out a compression fitting so that a piece of tubing would fit through it (to make a dip tube for a tank), and, with the absence of a suitable drill press vise, I simply held it in place with a pipe wrench (I think you see where this is going).
Well, long story short, I misjudged the torque the press could generate, drill bit got caught in the hole it was reaming, and the wrench went for a short ride that ended when it hit my forearm and broke the drill bit.
I wore safety glasses though.
EDIT: speeling