Damn Near Lost a Testicle to my 2X72 !!

Normark

Normark

Joined
Nov 7, 1999
Messages
6,651
Hey Guys...

Well first I almost kill my son's pure white Budgie in my 2X72, now this.
A few days ago I damn near lost my right testicle to the grinder...

I'm grinding away at some sheaths,, working on the left side of the grinder, guard Open working at the top of the belt,,slightly slack...

I move around to the right side of the grinder just to switch positions a little,,and then it happend...

I just started grinding when a Lightening Bolt of static electricity jumps from the open guard and got me on my right testicle!!

I damn near pushed my arm into the grinding belt!!

Ya Ya,,,Laugh as you may, but that Phucking Hurt!

I've also had Wicked mean sparks jump at least 2-3 inches from my tool rest to my stomach.... They are so large I can hear them over the grinder...
It's Not much fun,,and I'm scared $hitless to go near the blasted thing...

Ok Guys..

I have got to do something with the static coming off my grinder..

How do I stop the static build up ????

Any help would come in handy....

ttyle

Eric....
 
I've always sprayed my belts down with just a quick spray of WD40 while turning the belt by hand to both keep them cooler when grinding metal and also because someone told me a while back that it would help with the static also.
I still get a zap on occasion, especially when grinding titanium but nothing like a dry belt used to do to me.
STR
 
I was afraid to open this post!

You need to ground your grinder. Take a piece of wire and attach it to the grinder and the other end to something grounded, maybe a piece of conduit or something metal.

I get the shocks to the stomach but so far nothing below the belt, thank God!

Sean
 
Yeah, I forgot to mention I wear a leather vest I had made to cover me up good as well as some tight fitting kevlar gloves with latex rubber over that. Another old boy told me to get a humidfier in my shop because if the air was more humid it reduced the static charge. My shop is pretty humid on its own though being open and damp.

Try water on the belts if nothing else. I've heard that will reduce it even better than WD40 but haven't had enough of a problem to try it. The WD40 is more to prolong the life of the belts and keep it cooler I'm not real sure it does much for static.
STR
 
Eric

Your belt grinder is acting like the Van de Graff generator at the Ontario Science Centre. Yes, the one that they pull arcs several feet long from. The cold dry air in winter makes it worse. A humidifier will help. Grounding the frame of your grinder should help too. Hopefully, you have at least one metal wheel on your grinder. If all of the wheels are all coated with rubber, you will have to ground the belt using something like a piece of the tinsel garlands that you put on a christmas tree.

Phil
 
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.
 
Jumping at the wrong time can get you into big trouble. Shocking experience!!! When it gets really bad in the shop I spray a fine mist of water in the air from time to time. Any spray bottle that produces a really fine mist will work.maby that will keep your balls out of your watch pocket!!! :D Mike
 
Glad to hear your boys are OK now. I have posted in this forum a couple of times regarding what I can to to prevent static shock. My Wilton grinder shocks the living hell out of me from time to time, especially during the cold, dry conditions of winter. It is hell for me to grind knives intended for Christmas presents for that reason. I got struck by lightning about 25 years ago and plain ol static electricity will just about cause me to wet my pants....no kidding. I know all too well what you are referring to with respect to the 3-4 inch blue flame arcs! On my Wilton my recipie for disaster was to be slack grinding on top of the belt, where I was not physically contacting the metal in the grinder, again, on the cold, dry days and nights. It never really popped me when grinding with the 8" wheel, or when contacting the flat platen. Here is what stopped the shocking crap for me (99% of the time):

I got a 6-7 foot section of small chain at the hardware store. The links are about a half inch long each...the small stuff. On each end I put an "S" hook, one big one, one small one. I wrapped the belt around my waist and connected my "belt" with the small S hook. Make dang sure you are contacting skin around your waist with your chain belt...can't be on the outside of your clothes. Because it is 6-7 feet long, you will now have a tail about 4 feet long with the big S hook on the end. Hang that big S hook onto your grinder, or metal table, drill press, etc...whatever is metal and contacting the floor. I ain't no electrician and don't pretend to understand it..but the static that is built up in your body during slack belt grinding will just pass on through the body...the belt...and on through the floor. My dang Wilton stopped popping me when I did that little trick. Best of luck! You owe it to your boys to try this trick...it sure worked for me.

Hank Hammond
 
Hey Normark,did you take that avatar pic right after the zap to the testicles?:D :D :D
 
Never ground your self to a grinder or anything else for that matter!! If things go real wrong you could be killed and it is hard to make knives when your dead. Just pick up a can of "static guard" (get it in the laundry section at wall mart) and spray yourself the grinder and the belt. It should help a lot.:D
 
Godogs57 has the answer.It is called a static ground strap.I used to wear one when working on CMOS IC chips (a long time ago).
In the shop I have a 2'X2' piece of screen with the chain attached to it and hook the other end to the grinder.Standing on the screen dissipates most of the static.If it is really cold and dry I hook a strap directly to my body as well,by placing an ankle strap on and having it hang down the back of my shoe and touch the screen.All this ,of course, is crazy if your system is not properly grounded.Ground it to the electrical ground and to an earth ground (metal water pipe,ground rod,etc.) This will eliminate the lightening bolts.

BTW godogs57,I was hit by lightening twice.Once in 1962 and again in 1984.It happened both times at the scout camp and both strikes were in about the same place (less than 100 yards apart).Felt like someone hit me with a 4X4.No permanent damage,but I was a strange person to start.
 
Sorry to hear that Eric -- I get that all the time, especially when I start using fine belts and really get in close for detail stuff. :(
 
While you may think a direct connection between you and ground is a good idea, thinks again.
You get a short in the motor to its case,then mak contact with it while grounded, and you're toasted...
Maybe even if your shop wiring isn't up to snuff, you can get a floating ground, and the the ground current will be through you to earth ground.
A real static ground strap will have about 1 Megohm resistance from you to ground, so it bleeds off the static at a safe rate...
I'd check your shop wiring to make sure htere is a good ground return for your grinder.
Some anti-static spray would help, too.
 
Here's what I do: get a static wrist strap, attach one end to the frame of th e grinder. The grinder should be ground through simple fact you have it plugged into electrical outlet. When done the only way it should be done, which is the right way, the motor's frame and thus the rest of the grinder
is grounded. Both 120 and 240V plugs are 3 wire and one of them is "neutral",
which is grounded @ the breaker panel.

Anyway, attach the "wrist" end to the frame (spring clamp) and clip the alligator clip onto whatever you are grinding/buffing. Of course do it so that
the wire can not be caught by the rollers or the belt.

Assuming frame is grounded, static might build up on the belt itself and then,
when it builds up to sufficient voltage, it will jump onto closest object -which is typically whatever you're grinding and then your hand/body.

This is why grounding the object you're working on will do the trick.

If you don't have anti-static strap, use a piece of flexible wire. Again , from
the object you're working on to the frame of the grinder. Proper strap typically have a few MegaOhm resistor inline to limit the current.
 
I have got to do something with the static coming off my grinder..

How do I stop the static build up ????
Click to expand...

YOU are the one holding the charge when you touch the grinder and get snapped. The grinder is grounded through the motor plug ...so when you touch it...the built up charge on your body is discharging to ground.

The answer is in your shoes!!!

If you electrically insulate your self from ground...then a charge with build up on your body until you touch ground again. So, you need to ground your body to allow the charge to dissipate as it builds up. Some shoes will insulate you too much and you'll get snapped. When I wear tennis shoes....I get snapped. But when I wear my industrial safety shoes, I'm good! They have a "statis dissapative" sole which is a fairly common requirement for many industries where static can be a problem. Once you are aware of this self grounding concept...you'll see it everywhere...for example, you might see fork lifts with anti-static straps dragging on the ground.

I did a quick web search and this link popped up on top:

http://www.esd.tv/Shoes.html?OVRAW=...OVKEY=static dissipative shoes&OVMTC=standard


So, change your shoes...and you can forget about getting snapped forever. :)

Now I'm $.02 poorer. (hee hee)

-Rob
 
Another thing about these "ESD" shoes is that they have offer a controlled amount of electrical resistance...such that if your machine shorts out....it will short to the wired ground on the motor rather than to your body because your shoes have resistance...and electricity takes the path of lower resistance..i.e. the ground wire in your electrical cord.

there goes anutha $.02...:D :D

stopping while I'm ahead...Rob
 
As Howie said, you don't want to ground your body directly or you may get electrocuted! You also want the wire to be easily disconnected so that if the grinder happens to grab the wire, it won't pull your arm into harms way. The commercially available wrist straps have either a snap or plug to connect to the wire.

There are anti-static strips that you can tuck into your shoe. The strip then wraps around the bottom of your shoe giving the same effect as the ESD shoes that Ron mentions.

Digikey (www.digikey.com) sells an inexpensive wrist strap (16-1021-ND) for less than $11 and a shoe strap (SCP163-ND) for just over $8. These are the same as the ones used in electronics manufacturing facilities.

Phil
 
Thanks Rob, I'll send you 4 cents. sounds like the best and safest fix for the problem. If you would post a couple more times and get this up to a dime, it would make writing my tax deductible check more CENTS. :D :D

Thank you,

Bill
 
rfrink said:
YOU are the one holding the charge when you touch the grinder and get snapped. The grinder is grounded through the motor plug ...so when you touch it...the built up charge on your body is discharging to ground.
-Rob
Click to expand...

Do you mean that the usual autoparts-store drive belts connecting the motor- and drive- pulleys are electrically conductive? I never knew that.:o Thank you!
 
Do you mean that the usual autoparts-store drive belts connecting the motor- and drive- pulleys are electrically conductive? I never knew that
Click to expand...

Dang!..Mike...your are 100% correctomundo! I didn't think about that...my grinder is mounted on a steel plate with the motor...but many guys mount everything to a wood/plywood work bench. Hence the KMG grinder may not be grounded. In this case... I wonder if the ESD shoes will still prevent snappy discharges. Hmmm...I dunno.

OK Bill...you now have an open tab!!:D
 
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