Help with belt grinder tracking - general design

Hello guys!!! big update, the grinder is finished!! thanks to all of your replys is running nicely! basicly everything you recommended me was just what it needed to be done

so, i crowned the tracking wheel, flattened both iddler wheels, and then finished it.

i will leave some pictures!!

however, something really scared me off today, i was using the grinder today, sharpening some home knives, and i touched the end of a bolt, and it zapped me, an electrical shock. it was a minor shock obviously buy i dont know what caused it.

an importan note: today i changed the ground cable that goes from the motor to the ground terminal on the vfd, the old one was too short, and i replaced the old cable for a longer one, maybe i did something wrong? because with the old cable ive had not gotten a zap.

any ideas!! im scared to do anything know 😁😁


https://imgur.com/a/0zYXD5n


as you can see on the pictures, i have one cable going from the ground terminal on the motor, to the ground terminal of the VFD, and then another one from the VFD ground to the electric plug.

i was using crocs when grinding, yes i know is not the best shoes for working 😅, i dont know if that would make a difference.
 
taviii11 said:
Hello guys!!! big update, the grinder is finished!! thanks to all of your replys is running nicely! basicly everything you recommended me was just what it needed to be done

so, i crowned the tracking wheel, flattened both iddler wheels, and then finished it.

i will leave some pictures!!

however, something really scared me off today, i was using the grinder today, sharpening some home knives, and i touched the end of a bolt, and it zapped me, an electrical shock. it was a minor shock obviously buy i dont know what caused it.

an importan note: today i changed the ground cable that goes from the motor to the ground terminal on the vfd, the old one was too short, and i replaced the old cable for a longer one, maybe i did something wrong? because with the old cable ive had not gotten a zap.

any ideas!! im scared to do anything know 😁😁


https://imgur.com/a/0zYXD5n


as you can see on the pictures, i have one cable going from the ground terminal on the motor, to the ground terminal of the VFD, and then another one from the VFD ground to the electric plug.

i was using crocs when grinding, yes i know is not the best shoes for working 😅, i dont know if that would make a difference.
Click to expand...
You have likely experienced a static electricity shock. To be sure, though, first make certain the entire setup is grounded from the motor casing to an earth ground like a water pipe.
next, ground yourself. The Crocs isolated you, and the spinning belt generated electricity that built up in you until it arced back to the machine. Scares yer ass for a moment! To test this idea, see if you can find one of those wrist-grounding straps the computer repair guys use and ground yourself to the grinder. The "sparks" should go away. that then means doing something like wrapping a short chain around your ankle that grounds you to the floor despite the Crocs, or rig a clip from your machine to your waist or somewhere less unsafe than on your wrist whilst grinding.
Another trick is to keep a squeeze-mister of water close by and periodically spray the belt lightly.
 
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fitzo said:
You have likely experienced a static electricity shock. To be sure, though, first make certain the entire setup is grounded from the motor casing to an earth ground like a water pipe.
next, ground yourself. The Crocs isolated you, and the spinning belt generated electricity that built up in you until it arced back to the machine. Scares yer ass for a moment! To test this idea, see if you can find one of those wrist-grounding straps the computer repair guys use and ground yourself to the grinder. The "sparks" should go away. that then means doing something like wrapping a short chain around your ankle that grounds you to the floor despite the Crocs, or rig a clip from your machine to your waist or somewhere less unsafe than on your wrist whilst grinding.
Another trick is to keep a squeeze-mister of water close by and periodically spray the belt lightly.
Click to expand...
Hello fitzo, yes it scared me 🤣😅😅

I did another run of the machine with working boots, and i didnt get zapped 🤔, maybe the crocs where the problem. (Me being not grounded like you Said).

The machine Is grounded to the electical outlet, im expecting it to be properly grounded to a rod that goes to the ground, i dont have any Water Pipe near.

I didnt know you could ground yourself directly to the machine, so basicly a copper wire from my ankle to the grinders body Is a option?
 
taviii11 said:
Hello fitzo, yes it scared me 🤣😅😅

I did another run of the machine with working boots, and i didnt get zapped 🤔, maybe the crocs where the problem. (Me being not grounded like you Said).

The machine Is grounded to the electical outlet, im expecting it to be properly grounded to a rod that goes to the ground, i dont have any Water Pipe near.

I didnt know you could ground yourself directly to the machine, so basicly a copper wire from my ankle to the grinders body Is a option?
Click to expand...
If you "wire" yourself to the grinder body, make sure it is something "breakaway" with a clip or whatever so if it gets caught up somehow you can get away from it. Look up "grounding strap for computer" on Amazon and you'll see a nice thingy for this application that doesn't cost too much for what you get out of it in far fewer zaps.

BTW, I am very happy for you that you got the wheels/tracking straightened out and your new machine tracks well! Congrats!
 
I've experienced the same thing when grinding straight razors on a 4" wheel lol, my knuckles were grazing the tool arm the wheel was attached to. Scared me as well the first time it happened. Easy to build static electricity.
 
fitzo said:
BTW, I am very happy for you that you got the wheels/tracking straightened out and your new machine tracks well! Congrats!
Click to expand...
Thank you very much, im very happy too 😁

Another doubt ive got with all this grounding thing, the grinder baseplate Is bolted to am mdf wich Is itself fixed to the structure of the metal bench, should i conect a wire from one of the Bolts of the grinder baseplate to the metal structure of the bench? So everything Is grounded? Or ir doesnt make a difference.
 
taviii11 said:
Thank you very much, im very happy too 😁

Another doubt ive got with all this grounding thing, the grinder baseplate Is bolted to am mdf wich Is itself fixed to the structure of the metal bench, should i conect a wire from one of the Bolts of the grinder baseplate to the metal structure of the bench? So everything Is grounded? Or ir doesnt make a difference.
Click to expand...
Grounding the table isn’t necessary but it won’t hurt, either. What can be an important thing is to make sure the ground wire in your receptacle wiring is actually a ground. Electricians have a little lighted plug tool that tells if the circuit is grounded properly. You might borrow one of those and check the power/ground.
What zapped you, though, is static. Here’s a thought: strap your grinder across the MDF to ground to table. Put a grounding wire like that computer thingy around your ankle and clip it to the table. It’s all out of the way that way.
Try the occasional water spritz, too. That may be all you need.
All that said, make sure that power circuit has a proper ground.
“Good grinding”…
 
As said, it is static electricity, and it has nothing to do with your motor or power ground. A good earth ground won't stop it when it is cool and dry. Technically, it is a good earth ground that is part of what causes the static build-up.

A belt grinder is a simple version of a Van de Graaff generator. If the air is dry and cool, it will create quite a bit of static. Winter and dry climates like the American Southwest are the worst. Cordoba Argentina this time of year is cool and dry.
What happens is your insulated body (rubber shoes and dry concrete floor) becomes the reservoir for the electrons the belt steals from the earth, and when you approach a source of earth ground (the grinder chassis or other good ground), they discharge back to a neutral balance. The spark is harmless but can be startling.

Ways to deal with static electricity:
Use Static Guard - spray the back of the belt with Static Guard laundry spray - This usually stops it completely.
Increase the humidity around the grinder - If you grind with a mist spray like the Kool-Mist, you will never have static. If you spray a mist bottle of water in the area of the grinder it will usually stop the static. If misting, mist the floor, too.
Wear shoes with leather soles and stand on an anti-static floor mat.
Wear an ESD (electro-static discharge) strap on your shoe or shoes. This can be a simple strip of conductive material or very light chain that slips in your shoe and dangles on the floor behind you, or a little three-piece strap that slips on your shoe like a stirrup. This works best when the floor is static conductive but helps even on concrete.
Make a ground strap - It can be a 1-meter piece of 18-gauge flexible wire with a 25mmX75mm piece of copper or other metal on one end and a metal clamp on the other. Stick the metal plate in your waistband and clip the other end to the grinder. No need to attach it directly to your ankle.


When I did electronics for the government, I had to wear an ESD wrist strap to prevent frying the CMOS chips.
When working in the "Blue Room" (ATC control room), we had plastic strips that dangled out the back of our shoes (hospitals wear them in the ER, too.). The Blue Room was kept at around 55° and the air was as dry as they could make it. To make matters worse, it was carpeted to keep noise down. Walking across the floor would create a 1" spark.
For fun, we would take a fluorescent tube light and hold one end as we walked and shuffled across the carpet. Stick te other end out towards a grounded desk or the doorknob and the tube would flash like brightly as the static discharged and ionized the gas in the tube.
 
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