Top 10 Ways to Cut Metal - Without an Angle Grinder!
by Yonatan24 in Workshop > Tools
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Top 10 Ways to Cut Metal - Without an Angle Grinder!
Are you terrified of using angle grinders, like me?
After spending hundreds of hours over the past few years cutting metal & steel by hand for projects, in this Instructable, I will show you my beginners' guide for cutting metal and steel - what I wish I had back when I got started. These 10 affordable alternatives for an angle grinder should be ideal for weekend-DIYers, woodworkers, and beginner metalworkers who want to save money and work safely - well - most of them!
From hacksaws to jigsaws, and circular saws to...chisels?! This Instructable will cover them all!
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(Don't want to read this lengthy I'ble? Watch the video & see the tools in action & epic slow-mo fails!)
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Tired of skipping through boring DIY videos? In case you don't already know, I now make short, tightly edited Youtube videos about homemade tools, tool hacks, woodworking, electronics, metalworking projects and much more - Subscribe to so you don't miss out! :)
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Supplies
I will link to each tool and its accessories in each step, but I recommend these for all tools:
- Safety equipment (see my PPE kit)
- Bench vise (for holding materials)
- Bar-clamps
- Measuring and marking tools (see my kit)
- Deburring: Deburring tool, or X-acto knife, files, & diamond rotary tool disc (more about this in the next step)
Flex-shaft Rotary Tool ($70+) - VS a Dremel
Rotary tools - basically a faster drill, that cuts from the side? It's much more nuanced than that.
After starting with a Dremel, I've been using a Foredom flex-shaft rotary tool (abbreviated: FSRT) for the past few years and love it! My Dremel spins at a no-load speed of 35,000 RPM, however the motor is very small and weak, so it bogs down very easily. With a Dremel, I end up wasting half of my time waiting for it cool down, after it overheats every couple of minutes.
FSRTs are very different. There's a large external motor that rotates the handpiece (chuck) through a flexible shaft. The shaft is made up of a flexible plastic pipe that encloses a titanium coated spring which encloses a stiff spring-like rod which is what the motor rotates- all of which are flexible to increase maneuverability and reduce friction. Since it has a large, external motor, it's much stronger, and I've never come close to overheating the motor, even after hours of non-stop work. While it spins only at half the no-load speed (18,000 RPM), I still work at lower speeds because the motor is quite powerful, unlike my Dremel where I need to turn up the speed to compensate for the weak motor. Another upside to the FSRT is that it comes with a foot pedal, so I can control the speed with my foot.
I've also found that holding a Dremel can be uncomfortable, because you have to make sure not to cover the air holes that pass air through to cool down the motor. FSRTs also come with larger chucks, but this usually isn't relevant for cutting metal. Once I used a carbide burr to cut off a metal rivet, something I wouldn't have been able to do with a Dremel due to its small chuck.
One downside is that the flex shaft requires more maintenance, the inner shaft requires relubrication every 50 hours of use, and if you stall it (if a disc gets stuck, a burr catches in your shirt, etc) the inner shaft can break. Replacements are very cheap, though cleaning dirty grease is never fun and takes a while to clean up. After ~200+ hours of use, the handpiece in my FSRT overheats, likely because grease from the shaft got into the handpiece bearings and is increasing the friction, so I'll have to replace it or the bearings inside.
If you need a rotary tool for doing actual work, I highly recommend a FSRT because they don't cost significantly more. You can also get pneumatic tools, but I have no experience using any, and the sounds they make are unbearable to me.
This isn't to say Dremels are useless, they just aren't made for the work I do. They are more portable and can be operated with one hand, without the need for supporting the foot pedal - also you can get cordless Dremels!
There are three main types of cutting discs (wheels), with major differences:
- Tend to shatter immediately (see the video for slow-mo of this!)
- Wear out in less than a minute, faster than it takes to replace them.
- If you aren't cutting tiny pieces that require extreme precision and a thin kerf (cut thickness), these are useless.
- Not all non-reinforced discs are this thin, I've had more success with thicker ones, but can't find any unfortunately.
Fiberglass reinforced abrasive discs:
- Cut very fast
- Last much longer
- Less brittle, and are hard to break
- Don't fill the air with stinky abrasive dust, so they're great for working indoors or around sensitive components (bearings, etc)
- Are available in many different sizes
- Stay a consistent size, they don't wear out and get smaller.
- Cut slower than fiberglass reinforces abrasive wheels because the diamonds on the cutting edge wear out, with heat likely being a factor, though this requires more research.
- The sides of the discs are coated with diamond dust, which makes them amazing for grinding! I've had a single disc last for more than 10 hours of grinding steel. More about this in the step about the chisel.
High-tension Hacksaw ($15+)
Hacksaws are by far the simplest and most versatile tool - a must have for every workshop - but there are many different kinds - which is why this requires 2 steps!
In my opinion, the most important thing about a hacksaw is the ability to tension the blade. A high tension hacksaw is ideal, though as long as there's some type of mechanism for tightening it, it will work. A tight blade won't bend, is less likely to break, and will help you cut straight.
In terms of blades, I use blades with larger teeth (low TPI) for cutting aluminum because they cut very fast, and the rough edge they leave can be fixed quickly for soft materials. For harder materials, I use high TPI blades, usually HSS or bi-metal. The difference between them hasn't been noticeable in my experience, though that's likely because I cut scrap steel whose hardness is unknown, so it's hard to compare. The real question is simple at what point you replace the blade, but it's an economical question.
You can even get carbide grit and diamond hacksaw blades that can cut through hardened steel and other materials, though I've never used these. If you have any experience with them, I'd love to update this Instructable with your experience and credit you!
I've encountered this odd debate online about the TRUTH & FACTS & LOGIC & You're doing it WRONG of how a blade should be mounted in a hacksaw - which way the teeth should point. But I find it's not that complicated. Blades are meant to be used in a way where the force is applied in the direction in which the teeth point to. So there's no "correct" way. Before cutting, think of the position you're in, and whether it makes more sense and is easier to push or pull the saw, and that's how you should mount the blade. So if you're trying to cut an underground pipe, make sure the teeth point forward and focus on pushing the blade. And if a short kid is cutting a bolt that's mounted in a tall bench vise, make sure the teeth point backward, and focus on pulling the blade.
While you should let the blade do the work and not apply too much additional pressure, hacksaws can be a great workout that uses your whole body (I only realized this after spending a whole day cutting, and ending up with sore muscles that I didn't even notice I was using!), but a nightmare to use during hot summer days! And with enough practice and muscle memory, you'll be able to cut things very straight (see picture 6).
If you find that you aren't able to cut accurately with a hacksaw and can't afford more expensive tools, consider buying a miter box for your hacksaw (see this or this). Miter boxes usually come with additional slots for cutting at 45° miters.
Mini 6" Hacksaw ($5-20) - and More
Small hacksaws - Yes, there is a difference!
Small hacksaws use thinner blades that come in handy under many different circumstances. Thin blades allow you to cut faster and require the removal of less material. Very often, even the highest TPI blades (in large hacksaws) get stuck in thin material such as metal tubing with thin walls. I use mine mostly for cutting bolts, since the blades fits right between the threads of even the smallest ones, unlike my larger hacksaw where the blade can jump and "dance" off. I've even used it to repair the worn-out notches of an antique bar clamp!
Mini hacksaws are more of a light-duty tool and usually aren't as comfortable for continuous use, without much variety in blades, that break often if abused.
In the video, I also show a simple trick for cutting multiple bolts to the same size, and without having to worry about damaging the threads.
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In my experience, one-sided hacksaws that don't allow you to tension the blade are basically useless (see the 3rd to last picture). Instead of having to break blades, I made a small hand saw from a broken jigsaw, utilizing the blade clamp for replacing blades quickly! Metal cutting jigsaw blades are shorter, thicker, and stiffer (see the last picture).
Jigsaw ($40+)
While a woodworking jigsaw cuts faster than a hacksaw, I don't recommend it for long term use - if you have adequate alternatives. I've used mine to cut metal several times and it works - but it doesn't cut as precisely as I can cut with a hacksaw, and using it for long periods of time is an absolute nightmare, the vibrations destroy my hand and make it go numb, and there's plenty of research proving that years of prolonged use of vibrating tools can lead to nerve problems.
Trimming a small piece off the edge of the material I'm cutting can also be challenging because the shoe (base) needs to be supported on both sides, though I show a solution to this problem in the video - but it's not practical for multiple cuts. Sometimes starting the cut with a hacksaw can also make it easier.
When cutting steel with a jigsaw, keep your fingers well away from the shoe. I once had a blade catch in a piece of square tubing on the down stroke, and on the up stroke it came crashing down in my thumb AT FULL SPEED! Not something I would recommend - believe me!
However - with all that said, I don't think it's a tool that should be avoided: for making curved cuts in sheet metal it's ideal - but making straight cuts in thick steel - not so much.
Reciprocating saws, like jigsaws, also utilize a reciprocating blade. I've never used one so I can't speak in terms of vibration, and there is a wide variety of different blades you can buy for different materials - some of which might fit in a jigsaw blade clamp, despite being intended mostly for demolition work. I've also found this drill powered reciprocating saw attachment, in case all you have is a drill.
Circular Saw W/ a Carbide Tipped Blade ($50+)
I tried cutting metal on my horrible, antique, guard-less, drill powered circular saw, that had over a millimeter of play in the blade (arbor).
And to my surprise, it worked much better than I had expected - so well I bought an actual circular saw. I bought a corded Worx mini 710w circular saw. (If you're interested in this saw, I have a detailed 5-min review video on it)
First, I tried using my circular saw to cut aluminum, the same way I would cut wood - and it worked perfectly! It cut very fast (~30x faster than hacksawing), and as long I was careful, it left a smooth edge, even on a solid aluminum rod (see picture 5).
Next, I also tried cutting brass flat bar. Cutting it took more time, but it also worked very well.
After that, I moved on to steel, knowing it would be the hardest to cut. I adjusted the blade height and cut successfully through steel flat bar. Next, I tried cutting through stainless steel, and the blade just wouldn't budge, and I didn't want to push it through with too much force. The stainless didn't feel hardened, but suspecting it had damaged the teeth, I tried cutting through thin aluminum angle, which it cut through easily.
I quickly built an improvised chopsaw using an door hinge (don't try this!), and tried to cut through rebar, failing multiple times, and despite securing it properly, the rebar flew off while cutting, which I caught on a slow-motion camera - it's in the video! I didn't know if it would cut all the way through, but expected it to cut at least half way, yet it didn't budge. I have a few theories for why this happened, since I've seen rebar being cut easily with a carbide tipped blade in the past. The blade was damaged, the $3 carbide tipped blade I bought was very cheap and had low quality carbide teeth, they didn't have the right geometry, I was cutting at the wrong angle, and the hinge had way too much play in every direction - my fault.
This, as expected, destroyed the blade, breaking off half of the carbide teeth, so I moved on to the next step - cutting sheet metal! Vibrating and rattling material can break off teeth, so I decided to try something new. I clamped the sheet metal between two sheets of plywood, which I clamped to my workbench, effectively eliminating the possibility for any vibrations could ruin the saw blade. To my utter surprise, my circular saw managed to cut through it without stalling the motor, though I could clearly hear it was struggling, definitely something I will be repeating in the future.
Most circular saws are larger than mine, and using a small blade in a large circular might theoretically not be a bad idea because small blades are supposed to spin faster, and larger circular saws are supposed to spin slower. The slower the speed, generally the longer the blade will last. This is measured in FPM. Always follow the instructions and do your own research!
I reached out to two professionals with my questions, and here are their replies:
John Heisz: "Here's what experience has taught me: the deeper the blade is, the faster (and cooler) it will cut, but the greater the risk of snagging on the metal. - with the blade shallow, it will cut slower, run a bit hotter but is much less likely to catch on the steel. If you are cutting metal that's thick, (1/4" or more) it's better to have less teeth cutting the metal at a time, since the teeth can't snag as easily. So deeper is better in that instance." Though John has deleted his reply for an unknown reason.
Wide Vision Metal Fab started using woodworking blades originally because they were significantly cheaper than metal cutting blades, and claims they last the same amount of time: "I never had [carbide] teeth fly off or explode, but they could chip if in a bind. But the "correct" blades also can chip when in a bind. About the only difference I could tell between the blades was the metal chips. They seemed to be cooler and smaller with the steel cutting blade, which makes sense given the geometry of the teeth, and that wood is softer, which means more can be removed by each tooth." WVMF has since stopped using woodworking blades because they were too small by a fraction of an inch, and the price of metal cutting blades has decreased.
I didn't ask, and none have advocated for it - so try it at your own risk. If you have experience in these subjects, I'm curious if you have any recommendations regarding lubricating the blade, using diamond blades, and your overall experience.
In addition to standard circular saw best-practices and common sense, stay safe!:
- Always use safety glasses! The blade shoots tiny pieces of metal everywhere, consider also wearing a face shield
- Never remove the blade guard from your circular saw.
- Use a blade with as many teeth as possible. I used a 4" (110mm) 40 tooth blade. Larger blades should only be used if they have more teeth.
- If the blade suddenly explodes, will you be in the line of fire? Make sure your face, hands, legs, other people, or any windows won't get hit, and always stand to the side.
- Always make sure that the material you're cutting is not hardened steel. Try filing off a bit with a file, if the files slides off without its teeth biting into the material, it's hardened and should not be cut with a carbide tipped blade. Cutting hardened steel can cause the teeth to chip, sending small, sharp pieces of carbide everywhere very fast - and it the worst case it can cause the whole blade to explode.
- Don't overtighten the bolt that holds the blade.
- Don't use a blade with damaged teeth, inspect it before each use.
- Don't put a carbide tipped steel blade in a saw made for abrasive discs (the opposite)
- I've seen carbide tipped blades with large slots (I believe these are for cooling and reducing sound), and would avoid using them because they're likely more prone to bending sideways.
- If you plan on using yours a lot, I recommend investing in a proper "cold cut" metal cutting circular saw that's built for the job, with adequate RPMs and proper chip collection. Check out Milwaukee and Evolution.
Circular Saw With an Abrasive Disc ($50+)
An angle grinder cutting disc in a circular saw? I tried this a few years ago and got called every name in the book - for no reason, so I knew I had to do it again!
As I outlined in the previous step along with other recommended safety precautions, cutting hardened steel with a carbide tipped blade in a circular saw is a horrible idea. But how about using a disc that's engineered to cut steel?
I bought a $2 angle grinder cutting disc (also known as a cutoff wheel), but it wouldn't fit as it was meant for an angle grinder with a larger arbor. I rummaged around in my collection and found a washer whose internal diameter fit my circular saw, and whose external diameter was just slightly smaller than the internal diameter of the cutting disc. It fit, but was too thick, so I spent a few minutes sanding it down, and used it to bolt on the disc along with another thin washer to assist in spreading the clamping force. I recommend turning the saw on and off several times for a few seconds. It should feel and sound normal, if you feel any vibration, the disc is off centered and should not be used.
I decided to try it first on hardened stainless steel tubing (don't use these on soft metals) that dulled a hacksaw blade in less than a minute. Once again, I was surprised at how quickly and cleanly it cut, leaving a square edge with only a small burr. I also cut through the same piece of rebar from the previous step and threaded rod easily, with virtually no wear on the disc. So it's a huge success.
Other than the possibility of abrasive dust getting trapped in the bearings, I have yet to hear a logical explanation for why this shouldn't be done. Circular saws spin slower than angle grinders, have additional guards that protect you from the blade, and have a base plate that can help you cut accurately. The instructions for this saw say not to use an abrasive disc, though this makes no sense because it comes with a diamond blade for cutting - you guessed it - abrasive materials.
Shears ($10+)
Shears, also known as tin snips - I choose to use them whenever possible. As long as what I want to cut isn't too thick, the act of shearing will always be faster than cutting with a saw blade. They make quick work of angled tubing, especially steel drywall studs and aluminum angles. Cut, use them to bend, cut again, and repeat if necessary.
If you're planning to make many cuts, I recommend wearing gloves. Not only do they shear metal, but the continuous pressure creates a lot of shear stress between layers of skin and can cause nasty blisters. Also, whenever possible, I try utilizing something to press the shears against, my workbench, the floor, or (in) a bench vise, and use the weight of my body instead of the muscles in my hand.
Dull tin snips tend to warp/bend the material they're cutting, but if you have a rotary tool, there's no reason to have dull tin snips. All I do to sharpen them is match the angle which they were sharpened to originally, and remove a bit of material with a diamond disc.
Bolt Cutters ($20+)
Bolt cutters! ...In the name only?
I found these half-mangled bolt cutters (accidentally!) in the dumpster of a construction site. They were probably used on rebar, rendering the middle of jaws useless (though they can be sharpened!). Despite being able to use only the front part of the jaws, I've used them to obliterate almost everything I've tried so far, saving time cutting on materials I didn't want to cut by hand.
But there's a problem - one that leads me to believe they were called bolt cutters for legal reasons. Despite being called bolt cutters, they are completely useless as cutting bolts - if you want to reuse the threads.
But for cutting random steel parts - you can't beat them. I've even used them on hardened steel (this can be dangerous), they just cut everything.
A trick I've found for cutting large steel rods is to nibble away at them slowly with the tip of the jaws, then cut them, wedging the jaws into the rod. I used this technique to cut a large steel rod to be used as weights for a homemade light stand. I even tried cutting through pliers since I got the impression they weren't hardened, but failed (see the last picture).
I've never used them, but Knipex sell compact bolt cutters and flush cut bolt cutters that have one flat side than can be used for cutting bolts without destroying them
Chisel (0-$20)
This is the only tool that you need to make to be able to use, but it's very simple. I got inspired to try making it when I first saw Matthias Wandel using this technique to cut sheet metal for an electrical box. I would've never imagined it was possible.
It can be made out of virtually any flat piece of hardened steel: an old chisel, masonry chisel, flat screwdriver, spade drill bit, or maybe even a carbide-tipped chisel made for stoneworking.
I found an old chisel that was made in Japan, assuming its steel was going to be hard enough. I scraped away all of the spackle hoping it didn't have any asbestos, ground away all of the rust with a diamond disc in my flex shaft rotary tool, and used a fiberglass reinforced abrasive wheel to cut a new angle as close to square as I could, making sure to keep it cool. I'm sure I could spend whole week testing and optimizing the cutting angle (or even adding a micro-bevel), but I find it doesn't matter that much - the sharper the angle, the faster it'll dull.
If you show what you've done to a woodworker and they get mad, congrats, you can move on to the next step!
It's simple: use the vise jaws as a guide for cutting on the line, hammering and shearing metal as you go. It worked much better than I had expected, especially when the rectangular hole I made was too small, and I used it to carve away a few slivers of steel - faster than filing could ever be. (see the 2nd to last picture)
Ideally, I wouldn't hammer through the handle, but I couldn't think or a better idea that would still be easy to hold.
If you find the cutting edge is rounding over, here are several reasons for why that might be happening:
- The angle you sharpened the chisel to is too sharp.
- You're hitting hardened steel, which it can't cut.
- What you're cutting is too thick. Try cutting it slowly with the corner of your chisel
- Your chisel isn't hardened. It could be a cheap chisel, or it got too hot during the grinding process and the steel got annealed.
Brute Force - Pliers - Metal Fatigue - Improvise (it's Free!)
The last idea...is an odd mix of many ideas. I often find myself stuck without any tools that can cut metal, and have to improvise.
Pliers, can be used to bend small pieces of metal back and forth and cause it to break due to metal fatigue, a technique I've used many times. Sometimes I just use my hands to generate leverage and break bolts, welds, connections, etc. In one instance, the best way to break apart dozens of welds was to bash them continuously with a brick that was laying across the street. Violence FTW!
Once I was able to salvage four large threaded rods from an odd bathtub stand - I didn't have a saw to cut them off (it would have taken hours anyway), and I didn't have two wrenches to undo the nuts, so I just bent the steel around the bolts, bolt by bolt, until it broke.
Even More Tools!
Don't forget to watch the Youtube video if you haven't already!
Some more thoughts:
- I find that more expensive tools buy you accuracy and save you time, usually not much more.
- If you've bought any metal cutting tool and are happy or regret the decision, I'm interested in hearing why!
- If you're like me and love building your own tools, don't forget to check out The Ultimate Collection of DIY Workshop Tools, which contains dozens of Instructables on all sorts of homemade tools, perfect for your budget!
If my tools aren't don't suit your needs, check out these specialty & more expensive tools:
- Portable bandsaw (+ you can convert it). Also cordless Portabands (how adorable!)
- Drill-powered nibbler
- Abrasive chop saw (like step 6, but cuts more accurately & faster)
- Carbide blade "cold cut" saw: Circular saw or Miter saw. (like step 5, but more accurate & faster)
- Reciprocating saw. Also cordless ones, an alternative for hacksawing. And crazy carbide blades!
- Plasma cutter
- Impact driver powered shears
- Fein oscillating tool
- A uhhh... $100K Waterjet (Youtube)
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I read ALL comments, and reply to as many as I can, so make sure to leave your questions, suggestions, tips, tricks, and any other ideas in the comments below! - Thanks!