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While I was doing some quick research on Ryobi’s angle grinder (below), I saw this disturbing bit in the “specs” section of their site:

Included 4-1/2″ grinding wheel interchanges with industry-standard accessories such as wire brushes, chain-saw wheels, cut-off wheels, etc.

They don’t list any specs for the grinder in question, so maybe I’m out of line.  But I’d assume that for it to be effective as a grinder, it’s probably turning at least 8k RPM or better, in which case you definitely wouldn’t want to use a wire brush on it.

A grinder spinning that fast (or even 10k-12k RPM on a wired unit) can throw wire at amazing speeds — enough to shoot the wire right into your body.

If you want to use wire to clean off rust or paint, that’s a great idea; use a knot cut brush — I’ll find one and write it up for you shortly — and use a polisher designed to spin at less than 3k RPM.  It’s just as effective and much safer.

Oh yeah, and while I’m in annoying soap-box mode: don’t remove the guard on your angle grinder.  Sure, it makes it easier to get into tight spots and make it much easier to cut with, but it only takes once for a disc to come apart — and your life is forever changed.


12 Responses to Tip: Don’t Use Wire Brushes on Your Angle Grinder

  1. Jason says:

    What about the wire brushes sold for use with Dremels?

  2. Myself says:

    The force pulling the wires from their mounting is a function of RPM and diameter — a bigger brush will experience more force than a smaller one at the same speed.

  3. Doug says:

    There are wire wheels designed for angle grinder speeds.
    One example is here:

  4. James says:

    I recently bought my first angle grinder, but I haven’t had a chance to break it in yet. I’ve never used one before so I really appreciate the tips.

    I would love to see more articles like this.

  5. The Dremel brushes aren’t meant to be used at full speed, either – they’re for the variable speed models, and maybe also the little battery powered multi-tools that don’t turn that fast anyway.

    The edge speed of a little Dremel brush turning at X RPM is much lower than the edge speed of a big brush for a power drill, so the little wires hold in place better despite the higher speed of even a Dremel at a low setting. The smaller wires are also less dangerous, though they’d still punch into you pretty well at close range.

  6. eschoendorff says:

    I’ve used wire brushed on all sorts of angle grinders and I have NEVER had a problem.

  7. Chuck Cage says:

    eschoendorff: The guys on American Chopper have used angle grinders without the guard for years without injury, too. Give it time.

  8. Roscoe says:

    I highly recommend a full-face-shield instead of just glasses when you’re using a cut-off wheel on a grinder. It doesn’t take much to shatter a wheel, and you’ll be glad for the extra protection if one ever flys apart on you.

  9. kyle says:

    i have a knoted cup brush on my 11,000rpm grinder and have never had a problem

  10. FC says:

    use 3 m bristle brushes…no wires to worry about.

  11. Richard says:

    The folks thinking there’s anything slow moving about a dremel need to think again. 35,000 rpm is faster than any angle grinder. It those little bits and attachments didn’t spin so fast they wouldnt be effective. That’s how they can cut through a nail just as fast as a full size angle grinder. Their abdvantage is speed

  12. Casey Matherly says:

    I use an angle grinder every single day damn near it and the m************ are dangerous. Download to talk about the wire wheels a few weeks back I was using a wire wheel to take all the rust off a set of rims. At the time I didn’t notice but the wire wheel kept getting smaller and smaller when it finally got so small and that I couldn’t use it anymore I felt something weird on my leg for some reason I felt like I had a bunch of super glue or something on it. I looked down and much to my surprise I had about 75 pieces of wire sticking about a quarter inch into my leg LOL this is no bull s*** it took a while to pull every one of them out so that is a true story about be careful with a wire wheel on an angle grinder wear thick pants safety goggles a mask whatever but they do fly off. Another issue I’ve had it with a pair of sweatpants in the drawstring. God was watching out for this day because I almost had my dick mangled by the angle grinder because my drawstring got caught up in the will and within a Split Second it wraps my hands up so tight that it would have cut my dick off I’m sure luckily I just so had to be hanging to the left and not the right or I’ll probably would be resembling Bruce Jenner more than I would like

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