fishnaked Posted January 23, 2019 Report Share Posted January 23, 2019 I really like this grinder. However, after roughly only an hour of use, it has developed this habit of the grinding disc spinning off...AFTER I stop grinding and place the tool down. As it is decelerating, I can just watch the nut spin loose...spinning its way right off the grinder. It didn't do this when I first started using it. I thought that perhaps I had something on wrong. I've looked and see nothing obvious. I'm not new to this. I have a Makita and Metabo grinders as well. No problem. I've also used a variety of other grinders over the last 30 years. No problem like this before. I keep thinking it has to be something simple yet I see nothing. I tighten the nut as tight as I can with the included allen wrench. Makes no difference. I'm using the grinding disc that came with it. A cut off disc doesn't come off as often but...it does some times. I have no issues using sanding flap discs on it. Anyone experience this before? What's the solution? Quote Link to comment Share on other sites More sharing options...
Biggie Posted January 23, 2019 Report Share Posted January 23, 2019 Here's a guy that had a similar problem but I don't know if he ever found a solution. Quote Link to comment Share on other sites More sharing options...
fishnaked Posted January 23, 2019 Author Report Share Posted January 23, 2019 Thanks. Hope I can figure this out as the grinder isn't of much value to me if the disc comes off every time I shut it down. Very frustrating. Quote Link to comment Share on other sites More sharing options...
framer Posted January 27, 2019 Report Share Posted January 27, 2019 turn it off while the disc is applied against a surface. Quote Link to comment Share on other sites More sharing options...
fishnaked Posted January 29, 2019 Author Report Share Posted January 29, 2019 On 1/27/2019 at 12:07 AM, framer said: turn it off while the disc is applied against a surface. I started doing that towards the end of my last session with it. Works but is a pain in the rear having to retrain myself to use a grinder like that. Shouldn't have to. I contacted Dewalt but have heard nothing back. Quote Link to comment Share on other sites More sharing options...
method Posted January 29, 2019 Report Share Posted January 29, 2019 I thought dewalt nuts have a clutch in them. Have you tried a different nut? It may be faulty. Quote Link to comment Share on other sites More sharing options...
framer Posted January 29, 2019 Report Share Posted January 29, 2019 if the wheel is heavy or the motor slows down quickly, the wheel inertia loosens the nut. does the motor slow down quickly when you shut it off? perhaps bearings are going out. are you using the wrench to tighten the nut? Quote Link to comment Share on other sites More sharing options...
Big Adam Posted January 29, 2019 Report Share Posted January 29, 2019 Flip the nut over (opposite to the guidance stamped on the nut) I have to do this on my first-gen 4.5” Dewalt grinder. Never worked out why! Quote Link to comment Share on other sites More sharing options...
fishnaked Posted January 29, 2019 Author Report Share Posted January 29, 2019 12 hours ago, method said: I thought dewalt nuts have a clutch in them. Have you tried a different nut? It may be faulty. I'm not familiar with nuts with clutches in them. This one just has a plain ol' nut. Nothing fancy. Quote Link to comment Share on other sites More sharing options...
fishnaked Posted January 29, 2019 Author Report Share Posted January 29, 2019 8 hours ago, framer said: if the wheel is heavy or the motor slows down quickly, the wheel inertia loosens the nut. does the motor slow down quickly when you shut it off? perhaps bearings are going out. are you using the wrench to tighten the nut? The motor doesn't seem to slow down any quicker than it did when new...or any quicker than my other grinders. It runs smooth... and has about an hour on it or less.....so I don't think the bearings are going out. And yes, I'm using the wrench. Makes little difference how much muscle I put into the wrench either. Quote Link to comment Share on other sites More sharing options...
fishnaked Posted January 29, 2019 Author Report Share Posted January 29, 2019 6 hours ago, Big Adam said: Flip the nut over (opposite to the guidance stamped on the nut) I have to do this on my first-gen 4.5” Dewalt grinder. Never worked out why! Thanks. I thought I was being clever for doing that too. Unfortunately, it didn't make a difference. This thing has me baffled! I wish DeWalt would get back to me.... Quote Link to comment Share on other sites More sharing options...
Framer joe Posted January 30, 2019 Report Share Posted January 30, 2019 Bring it back I guess....I have the 20v and 60v grinders and no problems...hope it works out Quote Link to comment Share on other sites More sharing options...
method Posted February 1, 2019 Report Share Posted February 1, 2019 Or try a different nut from another grinder if you haven't already? If you have and it still happens maybe the thread is dodgy. Quote Link to comment Share on other sites More sharing options...
Paddy Posted February 3, 2019 Report Share Posted February 3, 2019 I have 2 cordless makita grinders and hand tighten the nuts on and then turn the wheel a little more but it's still really only hand tight so I can easily remove it and there has never been a time where it lossened up. The nut tightens in the opposite direction of the way the blade is turning so technically the blade should be getting tighter as its being used. Sounds to me like your grinder could be spinning in the opposite direction of how it should be going. Maybe some else would know if this is possible if there was a bad switch or the wiring got crossed somehow and making it run in reverse. There's an arrow on the top of the grinder head showing the direction of the blade rotation 1 Quote Link to comment Share on other sites More sharing options...
fishnaked Posted February 5, 2019 Author Report Share Posted February 5, 2019 Thank you all for the additional replies. DeWalt finally got back to me with a nice reply. They offered to send me a new nut if mine is worn but suggested I send the grinder to their service center in Salt Lake City. They offered to send me a return label. The nut isn't worn in any abnormal way for such little time I have on it. I'm going to inspect and tinker with it some more before doing anything. One thing I have observed is that the grinding disc that came with it seems to have a slight wobble to it... as it isn't balanced as well as it could be. I wonder if that could have something to do with it? After all, it is with that particular disc that the nut keeps spinning off.... though I think the cut off disc I have used on it came off once too... though I can't be 100% certain of that. Will keep you all posted as to the outcome. Until then, any other thoughts or ideas would be appreciated. Thanks! 1 Quote Link to comment Share on other sites More sharing options...
JakeDewalt Posted February 5, 2019 Report Share Posted February 5, 2019 Not worth the risk send it to the Service Center. Ok 1 thought Wrap the threads with Teflon Tape. I bet this works 😎 Quote Link to comment Share on other sites More sharing options...
Saujohn Posted March 12, 2020 Report Share Posted March 12, 2020 If not the thread, perhaps a bearing has gone. Disc usually tightens slightly while in use. Same thing happened to me I had to really tighten it and then the issue stopped. I might have swopped the bits with another grinder and swapped them back again Quote Link to comment Share on other sites More sharing options...
Biff Posted July 22, 2020 Report Share Posted July 22, 2020 I am so glad I found this. I just bought the 4011 angle grinder and was using it for the first time yesterday. I was using it with a diamond blade. After about 15 cuts as I powered off it through the blade. Scared the s*** out of me. Needless to say after reading this I will probably be getting another brand. Thank you! Quote Link to comment Share on other sites More sharing options...
Mike Shorter Posted April 25, 2022 Report Share Posted April 25, 2022 I had this same problem. I switched the polarity of the DC voltage. I put black to red and red to black. This reversed the direction of rotation on the disc and l have not had a problem since. Quote Link to comment Share on other sites More sharing options...
glass Posted April 25, 2022 Report Share Posted April 25, 2022 Solution. Throw Dewalt junk in garbage. Buy different brand. Quote Link to comment Share on other sites More sharing options...
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