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I have tried both thick and thin blades for cutting rebar. The thick one takes forever and is like smelting a sword. The thin one gets the job done but the blades I selected - limited choices at local hardware store - disappeared after a couple of cuts.

My preference would be to spend more for a good blade with the following characteristics:

  • relatively thin so that the amount of material grinded away is less
  • but long lasting
  • will not disappear causing lockup of the nut (i had to toss away my first grinder for that reason)

Do these types of blades exist? Most of them seem to be 6mm: I'd want 3 or less.

Note: there are two quite different needs:

  • cutting rebar to a desired length in a shop - with proper clamps and any leverage I want
  • cutting rebar inside retaining wall blocks that sometimes have significant accessibility challenges

For the second case it is critical that the tool be short length. Also I need to be able to cut as flush as possible

Update I did order this diamond tipped cutoff 1.5mm blade (which @Monkeyzeus had also mentioned in an earlier comment)![angle grinder cutoff blade

I also posted a separate question on how to replace/remove the blade in a locked up angle grinder How to replace grinder / cutoff wheel blades

source: https://www.amazon.com/gp/product/B07Q2B1TBP/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 .

Will report back after delivery.

WestCoastProjects
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    Whatever you do don't mount a metal cutting saw blade (made out of metal) to the angle grinder. Those can bind and jerk the angle grinder out of your hands causing a severe injury. Use manual bolt cutters, manual hacksaw, power reciprocating saw, or battery powered rebar cutter. – Jim Stewart Jul 13 '21 at 15:43
  • You could try [diamond cutoff wheels](https://www.homedepot.com/p/DIABLO-4-5-in-Diamond-Wheel-for-Metal-Cutting-DDD045DIA101F/301454106) – MonkeyZeus Jul 13 '21 at 19:28
  • @JimStewart It was an angle grinder blade not a saw blade. But I like the idea of manual tools: looking into that – WestCoastProjects Jul 13 '21 at 22:27
  • I got that, but I wanted to caution against putting on a saw blade. Someone could decide to try that if he was having trouble with abrasive discs. If I had not read about the risks of using a saw blade on an angle grinder, I would not know how risky it is. – Jim Stewart Jul 13 '21 at 22:34
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    @JimStewart Manual rebar cutters are $300 vs $30 for a decent angle grinder. That's a tough choice: i reallly do prefer the manual but wow that's steep – WestCoastProjects Jul 13 '21 at 23:13
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    Your grinder should have a button which locks the spindle for loosening the nut. Even if it doesn't, an impact wrench will do the job, or impact techniques using hand tools. If it doesn't have that button, "$30" might be the reason why. – Harper - Reinstate Monica Jul 13 '21 at 23:23
  • Angle grinders throw out a shower of sparks which could be a fire hazard. – Jim Stewart Jul 14 '21 at 00:12
  • https://youtu.be/NOg2jx7lvb0 manual rebar cutter demonstration. Harder than I thought. What about a battery powered reciprocating saw with the right blade? – Jim Stewart Jul 14 '21 at 00:28
  • reciprocating saw with a bimetal works but honestly it's kind of dangerous. A bandsaw works better but i've had issues with the belt coming out repeatedly. I gave up on it. – WestCoastProjects Jul 14 '21 at 01:03
  • Are you ignoring my diamond cut-off wheel comment on purpose? – MonkeyZeus Jul 14 '21 at 12:37
  • I think at the time of your comment I had not understood the term "cut-off" . I came to the same conclusion several days later and had not remembered about your earlier comment. I will update my "update" to state same. btw feel free to make an answer and I will at least upvote and based on results may become accepted – WestCoastProjects Jul 14 '21 at 15:06
  • Diamond wheels aren't suitable for metal. They're way too smooth and slow. – isherwood Jul 14 '21 at 15:09
  • @isherwood Is there a different type of cut-off wheel you recommend? – WestCoastProjects Jul 14 '21 at 15:13
  • Find a compromise between speed/durability, and quality/price. That's the case with any tool, of course. :) – isherwood Jul 14 '21 at 15:19
  • I've never seen a cutting wheel as thick as 6 mm. Are you sure you haven't accidentally bought a grinding wheel (meant for removing burrs, smoothing off welds and the like)? – TooTea Jul 18 '21 at 18:13
  • @TooTea You probably have actually: the wheels that are packaged with either of the two grinders I purchased are 5.2mm . As mentioned it is like smelting a sword to use them on rebar. I have a good setup now as shown in my answer using a 15mm diamond cutoff blade – WestCoastProjects Jul 18 '21 at 20:24

4 Answers4

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if you want to cut with an angle grinder use a cutting disc (also called a cut-off wheel) they are typically from 3 to 1mm thick. The thin ones are better because they cut faster.

For longer blade life try using lighter pressure

Jasen
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  • So for the criterion from my question `relatively thin so that the amount of material grinded away is less` . But I've tried some of these and they disappeared after a few cuts. Do you have a link to some example(s) that are thin yet durable? – WestCoastProjects Jul 14 '21 at 01:04
  • "flexOvit" is a good brand. I don't know if what you experience is faster than expected wearing out or not because I don't know what size of reinforcing steel you are cutting or or what size of disk you are using. if you have a lot of reinforcing to cut a mechanical cutter (bolt cutters, shear, etc) will be more economical. – Jasen Jul 14 '21 at 01:13
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I used a metal shear or rebar cutter.

Quieter, quicker and no electricity required.

Solar Mike
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  • Manual rebar cutters are $300 vs $30 for an angle grinder. That's a tough choice: i reallly do prefer the idea of manual but wow that's steep – WestCoastProjects Jul 14 '21 at 01:04
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    perhaps consider renting such a tool, or "borrow" one from e-bay or craigslist etc. – Jasen Jul 14 '21 at 01:40
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For cutting rebar, I use 0.040 cutoff discs. Light pressure gets me through 1/2" rebar in about 30 seconds.

Use a blade guard. These can break, but I have probably made 300 cuts in rebar in the last year, and I cannot remember breaking a cutoff disc.

If you can put the work into alignment of the thinner disc, not only will the rebar cut faster, but it will be cooler for handling after the cut.

Broken discs and locked nuts on the shaft are readily dealt with. The easiest approach is impact. I use an adapter to the nut on a standard 1/2" impact tool. Can be air, electric or hammer driven. The hammer driven ones are small and fit in almost any tool bag.

Since I have about 15 grinders, I have several different types of nuts. They fit into two categories: Hex nuts, and pin nuts. The pin nuts have round holes and some have hex holes. For the hex holes I simply use the right sized hex (Allen) tool on a socket mount. Usually 1/4" but I have one which is actually 6mm. For the pin ones, I have a old 1/2" drive socket which I welded 1/4" pins to. For the hex nuts, I just use the right sized socket, which is usually 13/16"

In the field, it takes perhaps 90 seconds to use a hammer impact and loosen the nut. In the shop it can be faster. However, it is very infrequent.

And just a final point, inertia is your friend. Do not use the shaft lock pin when using impact. No need to stress the internal gearbox locking pin. Let inertia be your friend.

mongo
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  • I mentioned the use of thin blades in a couple of places: that's not news. The blade guard is a safety factor to put something between the v high spinning disc and your fingers: but it does not have anything to do with prevening irrecoverable lockup in the nut/blade on the tool does it? – WestCoastProjects Jul 17 '21 at 22:14
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    You were looking for a solution, and I shared what works for me, and I have gone through lots of rebar building with concrete. So I affirmed the use of the cutoff wheels in a 0.040 thickness. If your primary problem was breaking the disc, or the nut getting too tight, when you failed to provide sufficient information to get a good answer. I will modify my answer to guess and speculate at details of your problem which you could have provided. – mongo Jul 18 '21 at 13:16
  • OK - I already accepted an answer about a cut-off disc but thanks for the additional details. Also thanks for that secondary info on loosening the nut. I will probably follow-up with a separate question on that. – WestCoastProjects Jul 18 '21 at 15:56
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My actual solution is along the lines of the comment by @MonkeyZeus and the accepted answer. After much research - and learning about the cut-off blades - I selected a diamond one and also got a more powerful grinder from a name brand Bosch. The results are quite good: a dozen rebars at about sixty seconds a pop. More importantly is the small and portable form factor - to the extent of a long series of extension cords being portable. I had a steep slope to do a bunch of rebar cutoffs and was able to grind down to within 1/4 inch of the ground and/or concrete with maximum six inches of clearance in any direction.

Bosch Angle Grinder enter image description here

Diamond cut off blade

enter image description here

Note It was very difficult to loosen the grinder clamp nut on this blade after use. I almost gave up.

WestCoastProjects
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    Show the other side of your "no-name" and we'll try to spot the spindle lock. Spindle lock and appropriate use of the wrench, typically with the body braced on the floor if it's bound up is how the blades are removed. – Ecnerwal Jul 18 '21 at 01:11
  • You should ask a new question about the locked up angle grinder. The answer space is not to be used for asking additional questions – Kris Jul 18 '21 at 02:10
  • @Kris OK I removed the question part of it and left as a note. – WestCoastProjects Jul 18 '21 at 03:11
  • @Kris I posted a separate question about the locked up angle grinder https://diy.stackexchange.com/questions/229443/how-to-replace-grinder-cutoff-wheel-blades – WestCoastProjects Jul 19 '21 at 22:38