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I have tried hack saw, manual bolt cutters, plasma cutter - all of which mess up the thread and make it tough to get the nut on. What's the best tool for this? Ideally something under $50 or something rentable? I have a lot of rods to cut (need to make about 50 cuts).

The nuts will be put on once and not removed. I can leave one of the ends unfinished so the nuts don't come off, but one end still needs to be pretty so I can get a nut on in the first place.

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    Have you tried a cut-off disc in an angle grinder?
    – Robert Nubel
    Commented Jul 27, 2017 at 20:33
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    Have you tried putting the nut on the rod, making the cut, then unscrewing the nut over the cut. At least with mild steel or brass, this cleans up the threads sufficiently to get a nut started.
    – Jim Stewart
    Commented Jul 27, 2017 at 20:34
  • Will try that. What about something like this attached to a power drill? amazon.com/BABAN-Diamond-Blades-Rotary-Dremel/dp/B015R3B40E/…
    – swinefeaster
    Commented Jul 27, 2017 at 20:36
  • Are the nuts on these rods going to be put on once and tightened or are they going to be put on and taken off multiple times?
    – Jim Stewart
    Commented Jul 27, 2017 at 20:44
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    Before you unscrew the nut after making the cut, you might try deburring with a file and then putting a drop of oil on the threads near the cut. This may help the nut clean the threads. If that doesn't work, perhaps a dab of diamond or cerium oxide polishing compound on the threads near the cut would grind the threads clean as the nut was unscrewed. Will the end threads near the cut be used to hold or will that protrude past the nut?
    – Jim Stewart
    Commented Jul 27, 2017 at 20:51

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I'm sorry, the right answer is a hacksaw. It will leave the threads very slightly burred, but that should come off with a wire brush or worst case a file. Your other methods will deform the thread by squeezing or melting, and that is harder to fix.

And run a threading die down it just to be sure.

The thing is, one tends to take for granted how bolts are made. When a nut starts easily on a bolt, that's no accident, the end of the bolt is finished for that effect. If you simply lop off a threaded rod - even if the cut is perfect, like a waterknife - it will still be awkward to start the thread because it hasn't been finished like a bolt.

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  • a threading die... cool didnt know about those. will try that out and report back!
    – swinefeaster
    Commented Jul 27, 2017 at 23:36
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    Yep, either a threading die or just grinding or filing down the starting thread down to the shaft...just like the factory does.
    – Iggy
    Commented Jul 28, 2017 at 5:47
  • reporting back - so i found that the real answer is learning how to finish the bolt. I ended up just using the plasma cutter to easily cut the rods, and then using a spinning grinder to file the bolt at a roughly 45 degree angle, which after you get the hang of it, finishes it off real nice.
    – swinefeaster
    Commented Aug 7, 2017 at 22:20
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A 4.5 inch angle grinder with a thin cutoff disk is the tool I'd reach for first, after threading the nut on.

If you don't have one but do have a circular saw, and the lengths you are cutting allow, an abrasive cutoff blade in the circular saw can also work. This one is listed for less than $2.50

cutoff blade

Expect sparks. Clean out all sawdust if you use one of these in a saw that you also use to cut wood with.

For larger scale projects they do make a 14" chop saw version.

You can additionally clean up the cut threads with a triangular file or a thread-restoring file.

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  • Is there a special "thread restoring" file?
    – Jim Stewart
    Commented Jul 27, 2017 at 21:51
  • Note to future readers: abrasive blades are great for this - either on an angle-grinder or a full chop/miter saw. However, while this will work just fine for 1/4" rods, these can easily have heat issues when cutting thicker metals, leading to melted metal making it harder to restore the threads; for these thicker rods, you might try a tungsten-carbide blade made for cutting ferrous metals - they cut a lot cooler and don't melt the metal. You'll still have some filing to do, but maybe not as much.
    – iAdjunct
    Commented Jul 27, 2017 at 22:22
  • I use a cutoff saw same as a grinder then bevel the end at 30 degrees after that remove the nut any burrs usually straighten out. Oil or grease is a good idea with threaded stainless because it loves to Gaul just a touch of grease reduces the chance of gauling.
    – Ed Beal
    Commented Jul 27, 2017 at 22:36
  • After using this well-suited product to cut the steel, one can gently bevel the edge of the cut, cleaning up the threads, allowing near-normal operation of the nut. Gently apply pressure as you rotate the rod, as these disks are not designed to tolerate much side loading. They are supposed to handle the occasional sideways bump and gentle contact with the steel rod would be within those limits. Stand to one side, just to be safe, but that's good advice with any activity on an abrasive disk.
    – fred_dot_u
    Commented Jul 27, 2017 at 22:40
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I know this question was asked ages ago but I have been using a really great tool I picked up in Australia. Its a hydraulic threaded rod cutter, been using it for almost three years now and never had to clean up the thread or chamfer the edge in between uses. The models ive got is the M-40L which is electric hydraulic and picked up their new portable manual hydraulic model (Model DW-400). These tools are awesome and cut like butter without even needing a hotworks permit. Company in Aus is called stainelec hydraulic equipment for those who are interested. Dw-400 model I bought

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  • Welcome to Home Improvement. Unfortunately, this answer reads very much like spam. If you'd care to edit it to indicate any affiliation you have with the company (or explicitly indicate "just a happy user"), that would help a lot.
    – FreeMan
    Commented Jul 9, 2020 at 14:53
  • looks like their website is down. maybe they went out of business. how much was the tool?
    – swinefeaster
    Commented Aug 13, 2020 at 23:08
  • In the US we've got rebar cutting tools that look just like this. Does this have some kind of softener to avoid flattening threads on either side of the cuts? My instinct is to buy rethreading dies to go along with this tool if it's to be used for cutting threaded rods.
    – popham
    Commented Mar 11 at 18:29
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Every electrician I know uses a cordless band saw. Cuts it fast, leaves the threads in good shape. Also works great for cutting EMT (conduit).

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    I'm not getting "under $50" vibes from this answer.
    – popham
    Commented Mar 11 at 18:31

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