What’s the Best Tool for Cutting Rods?
We get threaded rods in 1 meter lengths and then we cut them in thirds using this angle grinder. It works, but we’ve had the grinding wheel get destroyed during the process and send bits of the disk everywhere. We need a better solution.
So we’re asking you, because you might be an expert on this thing. What is the best tool for this job?
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28 Comments so far
Devon Jones
Try a metal cutoff saw, something like this:
http://www.amazon.com/Milwaukee-6180-20-14-Inch-Abrasive-Machine/dp/B00023S32W/ref=sr_1_1?ie=UTF8&s=hi&qid=1252008781&sr=1-1
It’s equivalent to a wood chop saw, but for metal. It will also ensure that your cuts are a proper 90 degrees, and keep you from bending the rod from the force of the cut.
John Tindale
A band saw is by far the best tool for cutting any kind of all-thread. I have installed commercial HVAC systems, and use all-thread to hand the unistrut that supports the unit, and I’ve made hundreds of all-thread cuts.
A band saw provides the cleanest, quickest cut. If you must use something like a sawzall or other recip, be sure to thread a bolt onto the rod before you cut, because you’ll have a hard time getting it to start after the cut is made.
I’ve also seen guys use a diamond plade in a chop- saw, but this can also leave a jagged cut if the blade dulls.
Tiago Henriques
What if i tell you guys that some days ago i was just asking myself exactly the same thing ?
And my idea was to ask you soon what is the tools you do use!
So far i haven’t yet found any better tool than angle grinder! hope some one in the comments have a better tool!
Steve Conklin
I think that power hacksaws are the best for production – they don’t heat the wrok like a cutoff wheel, they leave a smallish burr that a grinder knocks off easily, and they’re pretty fast. The downside is that they are more expensive. Here’s a link – just to provide a photo of what I’m talking about – I have no particular brand recommendation:
http://www.amazon.com/Grizzly-G9742-Metal-Cutting-Bandsaw-Swivel/dp/B0000DD0PL/ref=sr_1_1?ie=UTF8&s=hi&qid=1252008974&sr=1-1
Justin
The most efficient way is to use a band saw. That way the blade stays at fixed location. You set the work piece, cut, move work to next cut location, cut, etc. etc.
The way your doing it from the picture takes too long to move from one cut to next because your clamping/unclamping down the work pieces.
Justin
Actually if with a band saw you could tape multiple rods together, and cut them all at once.
David
I would use a Milwaukee portable band saw.
Chris
Well maybe you’re on the right track but you might be using the wrong wheel/disc. from the pic, I’d be cutting right next to vise (within an inch or you’ll get chatter on rod that thin) or create a dadoed base to cut into w/ a hinged apparatus (as mentioned below).
I use (since i found them to exist) “pencil discs” which have a kerf of 1/16th (or less) of an inch, as you might imagine the thinner the kerf the reduction of material being “ground/cut away” and the faster the cut & generally the more cuts per disc. These are amazing Sait makes them and you can buy them by the box or solos from industrial supply houses we have a great one locally http://www.KLJack.com or most any welding supply house , even Lowe’s has them made by Dewalt in 5″ but I prefer the Sait ones, if you have a die grinder they make an even thinner one like 3/64ths but in a three inch diameter super make worthy gear.
as with any abrasive disc especially the thin ones you need to be focused on a concise direct on even motion into your stock or you invite disc breakage/ binding/bogging. For a lot of repeats of motion hinging a sled to a surface and making a test cut ofcourse you can fashion a simple sled for the grinder w/ a simple stacked ‘holder’ with band clamps or temp screwed in cleats.
you grinder disc perpendicular to the cutting surface rod clamped in place in dado (the burn will be minimal (spray bottle @ the ready). the kerf is your guide to a mark on rod.
repeat cuts to stop block(s).
You then have tolightly grind the end to de-burr then spin a matching die on your end to verify ‘health of thread.
I think it’s easier than hack sawing and the disc freehand (with great care) is & can be an awesome detail ‘finesser’
Bruce Boettjer
I use a bench grinder. this leaves the best finish and the threads don’t get munged. I will thread on a nut first, cut the rod and use a wrench to remove the nut, in order to ensure that the threads didn;t get munged… I say this is the bet way because I like to ‘roll’ the cut surface around the grinding wheel edge, to deburr it… one less thing to get cut on
Josh Kopel
A metal cutting bandsaw is the best option by far, but it is pretty expensive.
For considerably less you can get a decent quality abrasive chop/cutoff saw with a built in vise. In addition it will let you add a stop at the exact length you need for repetitive cuts. At the very least your cuts will be square! As others said you may need to thread on a nut or use a thread cleanup file after cutting.
Jeffrey Matthias
As a designer for production, I agree completely with Josh Kopel above if your production levels are sort of high. Your best bet is a metal cutting bandsaw. These have a coolant system on them and cut very cleanly. Look for a used one. They are relatively basic.
If your production levels (for the rods specifically) aren’t that high, a cut-off saw works, as dos a hack saw and everything else mentioned by everyone else, BUT you will have to clean the cut ends up afterward. A well-tuned bandsaw will likely leave clean enough cuts to avoid a secondary process.
Good luck!
Datamancer
Chop saw. It’s like a miter saw but for metal. They are very inexpensive (under $200), safe, and you can cut several rods at a time. If you want, you can also thread a nut onto the rod, chop it, then unscrew the nut off the chopped end which will take the burr off and sort of re-thread the rod near the cut.
-~D~-
Jeffrey Matthias
The nut trick works to clean up the threads but it still leaves material hanging of the end. If you’re selling these to people, that won’t be acceptable. It also adds time to each rod you cut. You’re better off getting a horizontal bandsaw without coolant than a chop (cut-off) saw. Even a harbor freight one. Once again, though, you’re probably best off to find a used one with a cutting fluid (coolant) system.
Jeffrey Matthias
Also, in the mean time, cut closer to the vice. In the picture about, the distance from where the vice hold the rod to where it is being cut allows it to flex while being cut. It can then vibrate and change the angle of the rod to the grinder blade. This should reduce the number of wrecked cutting discs.
rmadams
Why not build a metal chop saw like this one: http://www.lindsaybks.com/bks8/dixon/index.html using the book “How to Build an Abrasive Saw Cutoff Attachment.” Cheap, easy and pretty safe, too.
Letsburn00@hotmail.com
In agreement with Jeff above, you want to get a machine where the vice is as close as possible to the cutter. Otherwise you’ll bend your rod, which will screw them up given they have to be 100% straight
dylan snow
This is rather off the top of my head. I’d like to hear how I am probably wrong from people who know more about industrial materials. That said…
Why do the threaded rods need to be metal? If you can go nylon (or wood) then you open the margins of your cutting options. Switching away from metal would reduce weight and thus reduce shipping cost.
(Wood might swell in humid environments, bad idea.)
I don’t think the nylon would bend/bow or wear down at the 1/3 meter length. However, it would give it a cheap plastic feel and I don’t know how the nylon would vibrate compared to the metal you use now.
Lastly, if you do stick with metal, Aluminum rods are lighter and might be easier to cut than most other metals. However, they are more expensive. But that expense might be offset by a drop in shipping weight.
To directly answer your question about cutting: plaid shirt, suspenders, beard, small axe, tiny amounts of liquid nitrogen and good timing. Then start a kickball team called Brooklyn Metaljacks.
You might be able to cut the nylon with a few passes of the laser cutter. After the initial set up you might save time because you can walk away while it does its thing on rows and rows of nylon rods. Pro: less loud noises. Cons: nylon fumes might be insanely toxic.
Hotproceed
Hello
You seem to be busy with shipment of Cupcake CNC.
I have good news to you. I have advice to see your photograph. The cutting of M8 rods 330mm long will be hard. Possibility you may know, but there is a convenient tool in Japan.
M8 rods Cutter
http://ctlg.panasonic.jp/product/info.do?pg=04&hb=EZ4540LN2S
It can easily to cut, and it can attach a nut without clean a cut end.
If you would like to get it, I can purchase and send it to MakerBot industries.
I hope for the answer of the last email.
Best regards
Hotproceed JAPAN
Tim
I use a metal cutting bandsaw like this: http://industrial.jettools.com/Products.aspx?Part=414458&cat=333042
It has a hand wheel to quickly clamp the material, and you can turn it on and walk away. When the cut is complete, it switches off.
I’d stay away from the grinding wheel tools. A bandsaw like this will cut all day long, is safe, quiet, and doesn’t produce any sparks.
Dominic Muren
Definitely a metal cutting bandsaw, or reciprocating cutoff saw (which can run with lubricant, cut thicker stock, and will have longer lasting blades, but be more hard to find, expensive) is the way to go. You can even cut a bundle of 20 rods at once!! Just hold them together tightly with tape on both sides of the cut — not the most A-1 safety method, but definitely fairly safe, and ridiculously faster than grinding. Plus you’ll lose less material in the kerf.
Nat Poate
Make a fitting for the anglegrinder like this…
http://twitpic.com/gfef8
Nat
Jonathan Foote
For small diameters, the “bolt cutters” on crimper/stripper tools work surprisingly well. One side is threaded and the other side is a blade that is flush. Not sure how useful for production quantities, and doesn’t work for anything bigger than #10, but thought it was worth a mention.
Conrad
My dad has a saw thats like a wood saw (the ones that you grab the handle and pull down) only it has a disk on it. he uses it to cut steel tubing alot…maybe thad help! Or try that band saw.
Ernie S
Try a very fine tooth metal cutting blade on the bandsaw in the picture with the lowest speed setting you can set it for.
Use “Tap Magic” cutting fluid, you don’t need much.
You can bundle the rods and bind them with a hose clamp near the cut to do more then 1 at a time.
Whatever you cut the rods with you will no doubt have to de-burr the cut ends to allow a nut to thread on.
Try a small bench mount belt sander (http://search.harborfreight.com/cpisearch/web/search.dokeyword=belt+sander&Submit=Go) for this with #80 or #100 grit belts.
Hold the end of each rod flush against the belt to establish a square end then spin it at about 45 degs. to put a ‘lead’ on the threads to start a nut with. Spin the end against a wire wheel after these steps to make a nicer job.
This method uses what you have (mostly), is safe and gives you more process options for other tasks.
You’ll find the belt sander is cheap so if it works for you maybe you’ll upgrade later to a better one, if not you haven’t lost much.
Hope this helps.
Chris L
Don’t bother with abrasive cutoff saws/discs.. They throw off too many sparks and too much abrasive dust and are incredibly noisy, not to mention the danger of shattering disks.
I know someone who almost cut off their thumb when the wheel on an angle grinder caught.. It’s just not worth the risk.
Portable bandsaw, with bi-metal blade. If you want to do one at a time, then you can use the saw by clamping the saw upright into a vise, turn it on, adjust the speed, hold the rod with both hands, one on either side of where you want to cut, then just push the rod into the blade and watch it cut. Alternately, if you can bundle a bunch of rods together and secure them, then you can use the portable bandsaw as it was designed to be used: start it up, carefully set the saw on the cut area and let the weight of the saw do all the work. Fast, safe, efficient. Not very expensive either – $89 at Harbor Freight:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47840
Oren Beck
Waterjet’s the best balance of total process value for a project like fabbing MakerBot in my view..As it has tolerances you are hard pressed to match plus it eliminates many secondary operations.
Tolerance Stacking is the demon that lurks in every initial part fabrication step. Meaning? if the rods we cut on Sept 1 are dimensionally off from those cut on October 1 we’re literally fabbing in an avoidable risk. Tolerances STACK with a vengeance often awe inspiring to the unwary. You of course likely know this but the readers may not:)
Hence, Making EVERY piece as Kaizen driven as we can is often barely Good Enough.
Back to your basic query? It’s needed to first enumerate the metrics of your situation.
as it depends on the volume of pieces and how “fast” you need the cutting done. THEN you narrow the field of methods by accuracy needed. The basic “Practical” cutting operations can be classed as abrasive material, toothed cutter, laser,plasma,waterjet flame and shearing. There’s debate over which method’s application is the best for a given situation. Based on what I call “total process cost per piece” A big enough laser may be MakerBot’s next generation capitol investment tied with perhaps a Waterjet. While waiting for that orbit’s cash flow? The low tech hack of “Air Whizzos” and largish diameter cutting wheels may balance all the Cost Vs Time Vs all else factors..
A cheapie Oriental Buffalo air whiz fitted with the largest diameter wheel “sane” to put on it will make reasonably short work of whacking allthread to length. Pre-threading several nuts onto the center of each length to use as cleanup dies is well worth making a process step. But you also might consider that an even semi-precise indexing flat for a drive pulley’s set screw improves overall “Tolerance Retention” dramatically. Unless you go for drilled and tapped threads that a thru bolt anchors pulley or stop collars with. If I were drafted to fab your parts I’d consider Heat Affected Zone issues from cutting as questionable to unlikely.
DW
Contact your bolt supplier (not the big box stores) and have your part made on a screw machine at the length you want. No cutting, de-burring or eqipment required. A good supplier will have the contacts. Run a cost analysis and you will find it will save you money. My cost for 1000 3/8-16X4 was about .20 cents each.
beeutrec
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