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I’ve got a hand-held angle grinder (Makita LXT, 5”). I’m using a wire brush in it to finish a long thin bit of steel (rectangular profile, about 3ft long, 5x15mm tapering to 5x5mm - it’s a sword blade, but it’s not sharp, so that’s probably not relevant)

It’s proving difficult to clamp the workpiece as it’s very thin. (Before everyone suggests ways to clamp it - I’ve got a metalwork vice, but I’ve not got anywhere to fit it outside where I use the grinder, so I’m using g-clamps. Also clamping round the part I’m working on means the grinder is mainly in contact with the clamp, which wastes effort and makes controlling the grinder harder. It’s difficult to grind beyond where it’s clamped as it resonates. So the most effective method has been clamping either side of the part I’m working on, but this is difficult).

I think it’d be easier if the grinder was fixed, and I brought the work piece to the grinder - I’d be able to hold it either side of the part I’m working on, and to feel the movement of the workpiece and compensate.

However, I’m conscious that this isn’t what the tool was designed for, but I know bench grinders do exist (I don’t have a bench grinder), and I think they give more control (which i presume is why they’re used for sharpening knives etc). Is this approach safe? If so, are there any precautions I should take?

  • If you only need your fingers for another day or so, I would say go ahead with your approach. Otherwise, get a bench grinder. Having fingers is worth a lot of money and trying to clamp down an angle grinder has too much risk for the reward in my opinion. You might be able to pick one up used on Craigslist pretty cheap if cost is the main factor. Otherwise, any bench grinder will still be cheaper than a visit to the ER. – statueuphemism Apr 29 at 11:52
  • @statueuphemism - thanks! I’m kinda attached to my fingers (emotionally as well as physically!) are you able to flesh out the risks into an answer? My main factor for not acquiring new tools is space rather than cost, unfortunately. – Dan W Apr 29 at 11:56
  • I would look to clamp the sword to a flat wood surface at either end with two other bits of wood and a couple of screws. Once ready, those wood clamps can be moved to get to the covered points. But your choice. – Solar Mike Apr 29 at 12:55
  • @SolarMike - thanks, that’s helpful - I’d been pondering that approach and will certainly go back to clamping it. I wanted to at least explore the idea of clamping the tool as I felt a bench grinder might work, but it looks like it’s not a good plan. As I’m keen not to increase my collection of tools, or decrease my collection of fingers, I’ll go back to clamping options. – Dan W Apr 29 at 13:02
  • @DanW yes, I like being able to count to 10... Stay safe. – Solar Mike Apr 29 at 13:05
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I do not think anyone should recommend that someone try clamping an angle grinder to a table rather than buying the correct entry-level tool (a bench grinder).

While clamping an angle grinder to a table could probably be done, the effort and skill required to make a clamping jig that reliably holds an angle grinder in place is high and the risks of doing it wrong are even higher. The jig likely requires wood or steel working tools where you would have already had a bench grinder in your shop for years before buying the tools required to make a jig to clamp an angle grinder.

To outline the risks: Basically, if the grinder comes loose while you are working with your fingers next to it, then your fingers are instantly a mangled mess either by the blade or by getting them crushed in the spindle.

  • That’s a good point - a clamping jig won’t be trivial especially due to the vibrations a grinder produces, and the awkward shape of the grinder with the battery pack. A saw a few safer looking ones on google images, but they definitely involved welding, which is a skill I’ve not got. – Dan W Apr 29 at 12:15
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Safe? Probably not the safest. Should you do this? Probably not, and if you do, do it at your own risk. I don't know what grinder you have, but the biggest risk here is to have something caught in the wire brush, like your clothes. To be safer, you should use a grinder that the ON button has to be held down in order for the grinder to work, rather than a SWITCH that stays ON or OFF. This way, you can clamp the button as well for example, so in case the grinder falls, or perhaps even moves, it shuts OFF. If you have to do something stupid, you have to think it through as much as possible. That being said, I have done this. Its one of those things you do because you have to but would never recommend to anyone.

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Since you ask about precautions: If you mount the grinder get some heavy leather gloves, I have lost skin a few times even with gloves on while using a bench grinder when the wire wheel grabbed the part and pulled my hand into the wheel , if I would not have had gloves on the damage would have been severe. The biggest problem is you won't have a platform to support the blade, it still may be workable just make sure not to let the leading edge of the piece get caught in the wheel only work the bottom 1/2 surface , flip and then the half, turn end for end and repeat, don't use much force and keep your hands away from the wire wheel. These are the precautions I try to observe on a wire wheel in a bench grinder.

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Is it safe? No, not really. Have I done it myself? Yes, as a metal worker in the army. (Didn't have a bench grinder on hand)

Though not recommended, if you are going to do this be careful. Wear some thick leather gloves in case something does slip loose. I used my welding gloves. (I shouldn't need to mention eye protection) Mind how much pressure you're putting behind your work piece on the grinder as to not dislodge it from the vise. That grinder could be spinning from 10-15k rpm and would make your skin look quite messy.

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