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Static shock from belt grinder?

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  • Static shock from belt grinder?

    At home I have one of those little cheap Delta 1" belt grinders. Every time I fire it up it builds up a hell of a static charge. I you don't constantly keep discharging it, pretty soon your going to pi$$ down one leg. How can I stop this? And no I don't mean pi$$ing down my leg, just the static build up. At work I have a Baldor and it never does this. Have any of you run across this?

    Scotty Moore

  • #2
    Where does the charge accumulate? What you have is essentially a Van der Graaf generator. Somewhere the belt is stripping off electrons and depositing them somewhere else. I suspect the issue is plastic rollers/plastic components. If you can figure out where the charge accumulates, replace that component with a metal one and then ground it. If it has a three prong plug, then you can just ground it to the metal frame/base of the machine.

    The Baldor doesn't have this problem because it has metal rollers and the belt is probably supported by a metal strip. All of these components are electrically tied to the frame which is grounded.


    • #3
      I'm going over to the shop tommorow, and I'll take note of the wheels on the Baldor. I know the bottom drive wheel is some sort of plastic, but I think the small top wheel just might be metal. I just never paid any particular attention to them. You may very well be on the right track. If that looks like the issue, making an aluminum wheel for the Delta shouldn't be any problem.



      • #4
        I'm not sure why your Delta machine has that problem. My stationary belt sander is an old one with a cast iron body and wooden roller wheels , and never generates any static charge that I notice. It even sits on a wooden table, and is powered by a V belt from a 2 prong plug motor. However, I would think that grounding the machine frame to a metal stand, or to a piece of steel sitting on a concrete floor would stop the static discharge through you. Are you sure you aren't actually feeling an electrical leak from the machine motor , which is for some reason not discharging through the grounded conductor?


        • #5
          I had one of those little belt sanders,all three wheels are plastic and it's a nylon backed belt going roundy round on them,so ya,perfect static generator.

          Mine only built up static when the humidity was low.
          I just need one more tool,just one!


          • #6

            This is a pretty common problem with belt grinders. Easiest fix is to just let some metal tinsel drag across the back of the belt to drain the charge to a ground.

            When I worked for Minnesota mining and Manufacturing we had such an arrangement on all the high speed slitters. Polyester back and cloth back abrasives would build a heck of a charge as it was being run through all the flexer rollers. It would be enough to knock you on your backside. So we used copper tinsel to dissipate the charge. It only took once to teach an operator to make sure the tinsel was in contact with the back.

            If you think you understand what is going on, you haven't been paying attention.


            • #7
              Take a closes dryer softner pad and rub it over the back of the belt while it is running. That will help if the problem is static. Be sure that it is static and not leakage. My switch went bad on the drill press and it started giving that tingling feeling. I have become very oriented to putting frame grounds to a driven ground.
              Byron Boucher
              Burnet, TX


              • #8
                I don't feel like it's leakage from the system, but that said, I also don't know how to determine if it is or isn't. This machine has done it since the day it was new.

                Today I was grinding out a small casting about 2" x 2" x 3" and had to keep tapping the casting against the corner of the table every 5-6 seconds to discharge the build up. If I didn't it would build up to the point it would arc across to get me. It was a very effective reminder.

                Thanks again,


                • #9
                  I have the same type 1" Delta belt-disk grinder, and same issue.

                  Stuff setting on the table does not get a static blast...... it's grounded. it's only when you are free-handing a part up in the non-backed part that it happens.

                  As for teh grounding..... the belt has a backing plate at table height, which does NOT discharge anything.... the belts are pretty decent insulators front-to-back.

                  Might need tinsel or points held just off the FRONT surface of the belt at a pulley.

                  Keep eye on ball.
                  Hashim Khan


                  • #10

                    I've got a 2 inch Kalamazoo that throws a blue arc off of it, that is reminiscent of the high frequency start from my TIG welder.

                    Baldor motor and a rubberized drive wheel - not sure what the upper roller is made from. Will have to check that. All I know is when I get within 1-2 inches of the belt, it lights my fire.

                    Pray tell.... where does one find copper tinsel???


                    • #11
                      Arc welding with a 2" Kalamazoo!

                      I have the 2" Kalamazoo -zoo - too, and man it's a shocker sometimes. Scares the daylights of me. I've wondered about some sort of makeshift ground strap on my wrist, but haven't tried it yet. Tinsel sounds like a plan if it can be found, or made.


                      • #12
                        Just do it!

                        Take a clothes dryer fabric softener pad and rub it on the back of the sanding belt with it running. If it doesn’t work tell me and I will have learned something. If it does work then you have learned something.
                        Byron Boucher
                        Burnet, TX


                        • #13
                          I have a 1" Kalamazoo with a Baldor motor. The drive wheel is plastic and the top wheel and platen are metal. It also has a 3 wire cord so it's grounded. I have never been bit off it yet and I've used it in all kinds of weather, high and low humidity and have ground parts without having them touch the base, in fact I've never given it a thought about getting bit. To start I would try a different brand belt, I think my belts are made by Sait.



                          • #14
                            Get belts with a cotton backing, not the plastic film type.
                            James Kilroy


                            • #15
                              I have two hard drive magnets mounted in the sparks path and that does a good job of catching the ferrous dust.

                              And the grinder fur will always be 'kissing' the belt and take away the charge.

                              (Plastic wheels is the cause)
                              " you not think you have enough machines?"