Damn Near Lost a Testicle to my 2X72 !!

rfrink said:
Hey Mike, That sounds like an early Pavlo experiment...and you're the test specimen. "hmmm..lets see what happens when we shock this guy!!" ..or else you're just a sick bastid who enjoys self inflicted pain for pleasure.. :) :)
Click to expand...

HEY! We're NOT going to talk about my sexual preferences on this forum! :D :D



rfrink said:
Here's another test....if you are getting snapped when you touch the grinder....then try to touch something else...say, your drill press...or water pipe. If you still get snapped...then you've eliminated the grinder as the host for the charge. There is no doubt that the grinder creates the charge...but for me...I think the operator carries it.
Click to expand...

I didn't make it clear enough that is exactly what happens to me. Reach over and touch the ancient Bader that's next to the KMG, and I get zapped, too. Sort of told me I was carrying the charge. I wear rubber-soled shoes, insulating me from earth. I have an epoxied-on insulative ceramic on the platen isolating me from the grinder. I'm holding a piece of metal against a rapidly-moving belt. Isn't that a recipe for building up a charge?


Edited to add: reporting on one last experiment and then I'm headed to the Badger Show.
1) Unhook strap from KMG and grind. Touch KMG....ZAP.
2) Grind on KMG and touch Bader (earth grounded, too)....ZAP.
3) Connect strap to Bader, grind on KMG. Touch KMG...no ZAP...touch Bader....no zap.
4) Remove strap, grind on KMG and take a few more shocks just for instant graticfication.......;) :D
 
Rob, I'll send the beer as soon as you send me a demo KMG and a pair of those shoes so I can justify refunding your 4 cents. :D :D Yep, I don't see buying you a beer either. :D :D

Bill
 
fitzo said:
Daniel, what part of, "It worked!" didn't come through about the strap?

My grinder is grounded (and has always been) to the water pipe as it comes out of the concrete in the floor of my basement and runs out to the mains in the street. That's a pretty good ground. Grinder to motor case, case to earth. Doesn't stop the static buildup though, and it doesn't happen if there's no ceramic liner......

Keep a finger on the workrest as one grinds and zap doesn't happen. Since I don't grind blades using a workrest, Mr. Pinky can't act as that connector, so I get zapped once I touch something metal. The static is building up in ME, not the grinder.

I got the strap and connected it, no ZAP. Disconnect it, ZAP. Experimentally, it sure seems like good observational evidence of some kind to me.

Now maybe that doesn't fit the theory, but it works; so, I think that sort of disqualifies your comment about it being a "myth". Now, personally, I don't much care how who solves their static problem in what way. I just reported something that definitely worked for me. I don't discount what PSO Phil said at all; he's one of the people I typically recommend for electrical questions.

I'm always ready to reconsider what I think I know, but what I observe makes it tough for me to ignore.
Click to expand...


One thing you might want to think about when you are using a water pipe as a ground.If you have a electric water heater and the heater element starts to go bad,you will get a shocking condition from your grinder.
I am a lineman down here in Alabama and when a customer starts complaining about their water pipes shocking them.We inform them that he or his buddy next door has a water heater element going bad.The element will still heat water,but it will also bleed voltage into the water and the metal pipe.
If you have a gas water heater ,then you have nothing to worry about.
 
you are all talking like an occasional blue zap to the boys is the bad thing...thats just crazy talk..
 
Fitzo - I don't doubt that your wrist-strap experiment works...but you are not solving the problem and are risking shock to other parts of your body not "covered" by the wrist strap.

And I don't think anybody here is going to wrap one around their...well, you get the idea. :eek:
 
While one can get some static on himself by wearing some synthetic/wool in dry cold air (shop etc), by far the largest charge comes from the belt's cloth/synthetic backing rubbing at some really high speeds against platens etc.

If one has ceramic/glass platens like most of us, that's the worst.

When grinding, the charge will leask off the belt onto object being ground and onto the operator's body.

The voltage builds up to few KV and then it jumps the shortest air gap between the operator and whatever is ground, typically the grinder frame.

If one's family jewels take a swing really close to the frame, then that's where the sparks will fly. In most cases, it goes off one's hands.

To prevent that, don't allow the charge to build up on the belt and/or object you are grinding.

Grounding the object solves this problem. Grounding the operator doesn't solve the problem 100% - you will still get smallish sparks off the belt and onto the operator.

Another thing that helps is to wrap a small strip of alum sticky foil around a portion of the platen, in a way where the foil would contact the back of the belt. Assuming foil also touches grinder's frame (which MUST be grounded through being properly wired) it will work 100%.
 
Grounding any portion of one's body would take care of static, as we are rather conductive creations (100s of KOhm). Grab two leads of an Ohmeter set to resistance measuring mode, with 2 hands and you will see some resistance shown, it won't be an open circuit.

One must have an open circuit for the charge to build up. Any resistance,
even in MOhm range, will drain the static and not let is build up.
 
Hey Guys....

Thanks for all the advice...

What if....

I were to install a contact, that is grounded to the grinders frame, that sits inside and rubs or is very close to the inside of the drive wheel, kind of like a spark arrestor that drags along the pavement from a car...

Which BTW I get shocked with as well...
As soon as I get out BOOM,I get zapped...

Anyway,, would that work, by grounding out the drive wheel ??

ttyle

Eric...
 
The electronics manufacturing industry has put millions of dollars of research effort into the issue of static control and suppression because it is a real problem. The results of all this research is that one can either shield the sensitive object from the static charge or get everything at the same voltage potential by bleeding the static charge away. There are millions of dollars of static control equipment and consumables sold every year because it works. You only really need some basic stuff in knifemaking.

Since you cannot shield yourself from your grinder and still work with it, your ultimate objective becomes getting your body and the piece of equipment at the same voltage potential. The easiest and surest way to do this is to connect your body to ground through a static-dissipative wrist strap or ESD shoes (or shoe straps) with static dissipative floor mats AND to connect all parts of the machine that can develop and hold a static charge to ground. The wrist-strap and floor mats must be connected to a ground to work. Grounding the frame of your grinder does not take care of the electrically insulated parts like the belt. The picture posted by Mr. Wrong will work if the rubber strip is changed to something more conductive. As Rashid stated, it does not matter which part of your body you put the strap on. Toxey's post gives another reason why one must use a resistive connection to one's body; grounds can "go bad" (see http://www.3m.com/market/electronic/ehpd/technical_papers/article04.jhtml). The idea of sraying fabric softener will work as long as the coating covers most of an insulated part and "connects" it to a grounded part. There is a commercially available anti-static spray, called "Staticide", that does exactly this. A humidifier will help too since the water vapor is slightly conductive and "connects everything to everything else". Some electronics manufacturing facilities use all of these measures.
 
When I worked in larger scale chemistry, we always had to "bond" everything together in any fluid train to prevent any static charge buildup. We had jumper cables that we would connect a tank to a metal pump housing, back to the next tank in line, and then tank to tank and finally to the thick bus bar earth grounds we had everywhere. Otherwise, a static charge would build up from the moving liquid through the non-conductive rubber hose or teflon-tapeed pipe fitting and could spark when it went into the tank, especially if it was a freefalling stream.

I see the wrist strap as the same type of "bonding", that non-conductive pyroceram as the hose, and the belt as the moving liquid.

Someone correct me if I'm wrong, please. :)

I've considered a small piece of copper tape, like Rashid suggested, but I'd like to cement it in place. Does anyone know of a conductive adhesive? JB Weld doesn't do it, despite being metal-loaded.
 
take a small brass bristled brush, such as one for a Dremel, connect it to ground, then mount it so it barely contacts the inside of the belt. (or something similar, like rfrink suggested)
It would bleed off some of the charge being generated.
Even if you don't have a platen, the belt going across the contact wheel rubber generates a charge, too.
 
rfrink said:
PJ....Tell me about your KMG. That's an early one! Wow!! it looks great! When and where did you get it? QUOTE]:o :o

Im still saving for one "im too poor". I copied that picture some time ago.. But since this a topic about losing testicles I would give up my left one for a fully loaded kmg setup.:rolleyes:

Pj
Click to expand...
 
Knock on wood. I feel lucky, I,ve never been shock by my grinders. But have been shocked by spark plug wires and electric fenses.
 
raylaconico said:
I used to get shocks to my fingers when my grinder was new but not anymore. I didn't do anything to it. It just stopped.
Click to expand...

I think you'll find you changed your shoes..

Robs right
if you guys know what and how a magneto works you'd understand..
static ele is a whole different ball game then your grinder set up..
you body is acting like a automotive condenser building a static charge
once grounded ZAP..a discharge ..
change your shoes to non insulated...so the charge can't build up

I have a wilton
setting a on full steel welding table setting on cement and the wiring is right.
if the motor is not grounded it won't work right,, it's a whole different problem, voltage and amperage wise..
like Rob said
change your shoes,
work bear footed to prove it to yourself..
if your grinder is set up and grounded correctly you don't have to worry about that part of it..
 
Be careful with that !

If enough charge builds up on the belt, while idling and then, while
standing on grounded matt, you start grinding, the charge will go
through your arms, upper body and into the matt through you legs.

Worst thing that can happen is for current to flow through your heart.

Worse yet, if grinder's frame goes hot, it can drive enough current
to stop your heart. It will be nearly impossible to withdraw your hands
off the frame, as you loose control of your muscles when shocked like
this.

The static dissipating matts were designed to bleed off NATURAL
static of your body, not to ground dangerous voltages.
 
rashid11 said:
Be careful with that !

If enough charge builds up on the belt, while idling and then, while
standing on grounded matt, you start grinding, the charge will go
through your arms, upper body and into the matt through you legs.

Worst thing that can happen is for current to flow through your heart.

Worse yet, if grinder's frame goes hot, it can drive enough current
to stop your heart. It will be nearly impossible to withdraw your hands
off the frame, as you loose control of your muscles when shocked like
this.

The static dissipating matts were designed to bleed off NATURAL
static of your body, not to ground dangerous voltages.
Click to expand...
your confusing reg house curant with static
the platen will not built static your body biults it.

if the grinder's frame goes hot you have a wiring problem, it's not what's happening here, it's static, high voltage and very low amp and it's not alternating curant. also house curant can not jump even 1/4"
 
Doesnt it only take 6 miliaps across the hear to stop it? I thought this was the reason they dont do static electrcity experiment in schools anymore....
 
TikTock said:
Doesnt it only take 6 miliaps across the hear to stop it? I thought this was the reason they dont do static electrcity experiment in schools anymore....
Click to expand...
it all depends on your heart and when, you can get slaped in the chest at the right timing of your heart beat and die deader than a door nail.
 
You must log in or register to reply here.
Back
Top