static shock

J

Jon Christensen

Joined
Jan 28, 2000
Messages
155
Say has anyone else had this problem. When grinding (not using the work rest)I get a shock as soon as i touch my grinder to adjust or turn it off. It's not an electrical shock but just a quick static shock. I cured the problem by holding a ground wire which is attached to the grinder case. Would like to know if this is common or not. My grinder is a 2x48 from KBC, an inexpensive grinder but it does the job.

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The mass of men lead lives of quiet desperation.
 
Jon,

Happens every winter here. I think the drier winter air has something to do with it because in spring and summer it's not a problem.

I fixed it the same way you did, with a ground wire attached to the machine and held to my forearm by an elastic wrist support band. Make the wire long enough to allow full freedom of movement.

It gets real annoying to get zapped like that every time you touch the machine.

Good luck on your grinding.

Gary B www.toptexknives.com/bradburn.htm
 
I heat the shop with a wood burner in winter. To avoid static from dry air I keep an old pot full of water on the woodburner. It provides enough moisture to not only help stop static but to make breathing easier. Maybe a cheap humidifier would work for you guys.

Jake

 
Jon,
The biggest part of the problem comes from what Jake said, low humidity. If you can keep the humidity above 55% static won't form. Another thing.......if you have an anti-fatigue mat, or other rubber mat that you stand on, that isn't grounded, your gona get zapped! Next time your up, ask me about that, and I'll tell you a real embarassing story of getting zapped where you would least like to be zapped. Take Care,
http://www.mtn-webtech.com/~caffrey

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Ed Caffrey
"The Montana Bladesmith"


 
I have a pair of shoes that have some sort of rubber sole. I get zapped quite frequently. I will have this happen fairly often when buffing. I am well insulated while wearing these and it gets me when I least expect it.

C Wilkins
 
Man---
You guys ain't no fun, how do you plan on staying awake if you fix the problem. Thats what keeps me going.

I have a wide belt sander in my shop with a safty stop thats butt high, every time I run around to the outfeed table I get zapped, what a wake-up call!!!

Any ideas--

John Yeackley

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http://www.toptexknives.com/yeackley.htm My contribution to the world of knife fanatics.


 
Thanks guys, Was driving me nuts till I put the grounding strap on. Unfortunately Shepherd is a real dry climate and I heat with propane so may not be able to fix the problem so easy. Nice to hear that I'm not the only one being effected by it. Thought it was just my static personality. :-)

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The mass of men lead lives of quiet desperation.
 
Jon and everybody else,

Please do not use a grounding strap, You are running some very powerful equipment there and one small error, a misjudgment, a act of God, and you will wish God was with you.

That wire could get caught up in the wheel, belts, gears, motor, whatever, and it will rip you into the "beast" before you know what happened.

I also get the "kiss" of a static charge when using my buffers.

As it has already been put forth, the best way to dissipate the charge is to ground it out. I use the blade... Hey, I'm holding the blade anyway and just tap the housing everytime I glance at the progress and the charge is gone, since I have a good grip on the blade, there is very little sensation of dissipating the charge as compared to the "bite" when you least expect it...

It just takes a little discipline to develop the habit, a post-it on the housing helps to remind you to "Charge-It"...

Please dump those discharge wires before someone gets hurt!

Bruce
 
Wouldn't it work if you just put a ground wire from the machine to the ground wire in your house? The ground that goes to the nearest water pipe is what I am thinking of. If anyone has tried it let me know. I get zapped everytime I use my buffer!!!
 

Phezzer, I think the problem is the static charge that is built up in you; not in the grinder. My grinder is already grounded with the 3rd wire of the power cord. It's me that isn't grounded until I touch the grinder or anything else that is grounded and then I dump that charge with the familiar "WOW" sensation. A grounded mat to stand on will help, but not if you're wearing rubber sole shoes. It's just like the car with a downed power line on it. You're ok until you touch both the ground and the car and then you're dead. I got used to wearing a grounding strap while working with electronic equipment; not to protect me - to keep that static charge from frying some sensative chips, but I'm also reluctant to wear any kind of strap when working around moving things.
Ron


[This message has been edited by Ron Peek (edited 01-31-2000).]
 
The static charge is most likely being built up on your equipment due to the motion of the belt relative to the air, the tribo-electric effect. When you touch the equipment, your body takes some of the charge, causing you to feel a shock or tingle. This will happen whether you're body is "isolated" or not.

Increasing the humidity in your workshop will help dissipate the static charge. The ultrasonic units work great for this.

It may help to attach a ground wire to your grinder, say the platten, to help bleed of some of the static charge.

I use wrist straps at work (electronics R&D) for the protection of the equipment that we use and develop. If you are going to use them, PLEASE get a proper anti-static wrist strap. They are available from some of the wholesale electronics distributors (probably not at Radio Shack) and possibly some safety supply houses. You might ask your local, big name computer service depot (Compaq, IBM etc) where they get theirs. There are two styles. One is stretchy fabric bracelet. The other is an expanding metal bracelet, like the Spiedel watch bands. Both have a snap button to attach your ground wire. In a knifemaking application, if the wire gets caught, it will just pop off your wrist without pulling your precious hands into the machinery. Get the style of ground wire with a "banana plug" on the other end and buy a matching socket from, say, Radio Shack. It is much more convenient that way. Finally, connect the socket to the third prong of your power cable, or the body of your grinder, through a 1 MegOhm, 1/4 Watt resistor (available at Radio Shack too). The resistor may be soldered to the end of the socket. This last step is CRITICAL. If you leave out the resistor and touch something that is electrically live (say a piece of equipment with faulty insulation), you can be ELECTROCUTED! Someone who works in electronics R&D or computer repair could probably help you set this up.

I hope this makes sense. If you need more info on how to set this up, send me an E-Mail and I will fax you a sketch. Setting up a wrist strap wrong can get you killed. Then I wont be able to buy your knives, and I wouldn't want that :-)
 
Static is a problem I must admit but I have found that footwear can have a big effect on the amount of static I experience. Running shoes are definitely out, their insulating characteristics increase the amount of static shocks. A pair of leather soled shoes reduce the amount of static shocks, probably because the soles absorb moisture from perspiration and other sources and help dissipate the amount of static to the floor.

Static won't kill you but the distraction it causes can.

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george
www.tichbourneknives.com
sales@tichbourneknives.com




[This message has been edited by george tichbourne (edited 02-01-2000).]
 
why not try to ground the grinder to a pipe like a water line .this would probably work better than tying one to your wrist.
hope this helps you.david lovins

 
Grounding the grinder won't to a darn thing to stop the static. Static is created by the movement of the belt or buff in the dry air and is transferred to the metal being polished then through you to the floor or any other object that is grounded. Bleeding off this static charge that is building up on the surface of your body is the only way to prevent being zapped.

Higher humidity will prevent the static being created in the first place but that is not always possible to achieve.

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george
www.tichbourneknives.com
sales@tichbourneknives.com


 
George is right concerning the static and shoe wear. I hinted at that in my previous post. Best case for static elimination would be to stand barefoot on the bare floor while grinding or buffing but due to safety reasons and pneumonia, I wouldn't recommend it. Leather soled shoes are much better than rubber or any other well electrically insulating material.

Two other recommendations and one has already been touched on. Touch the machinery with the blade you are grinding or buffing. This will discharge the static without the "ouch" involved.

The other is that if you have to wear a ground strap, put it on your ankle (until you get tired of it, then wear leather soled shoes or boots)
smile.gif


If you do wear a ground strap (on your ankle)at least look into it and possible place a resistor or even a fuse in series with it "just in case" you get across 110VAC and wish you never, ever even thought about dissipating static. Make sure that it is well away from ANY equipment, especially the rotating kind.

By the way George, the finger is healing just fine!

C Wilkins
 
i don't have a shock happen to me to often, unless i have metal splinters in me, then the buffer shocks me. i have a 12"x 2" wide buff on there, so know i'm no where near the motor casing, and don't get shocked.
 
Hey Guys...

Yup I've got the same problem grinding Concealex....

Bruce!!!

Thank you for bringing up the strap and safety issue!!!

I was just going to say that myself!!
Can be a Dangerous situation...

Another thing you guys might want to think anout is the clothing you are wearing!!!

Going to start a thread on Shop Safety!!

ttyle Eric...

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Eric E. Noeldechen
On/Scene Tactical
http://www.mnsi.net/~nbtnoel
Custom made, High Quality
Concealex Sheaths and Tool Holsters
Canada's Only Custom Concealex Shop!

 
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