In yesterday’s post about the new HK Porter PowerLink double action bolt cutters, Jerry left a comment saying I’m waiting for ratcheting bolt cutters… I would think the same principle would work with bolt cutters.
Fred replied with: Maybe Stuart can comment on the science of this – but I think that ratcheting pruning shears and ratcheting cable cutters work by cutting or slicing through a few fibers or strands at a time. With bolts, padlock shackles, threaded rod, chain and rebar there are no strands.
So I gave it a little bit of thought, and I’ll ask all of you the same question. Is there the potential for a brand to come out with ratcheting bolt cutters?
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Maybe I’m wrong, but here’s what I think:
I don’t think there’s much hidden engineering or science behind ratcheting cutters. There are ratcheting PVC cutters as well, so the concept doesn’t just work on stranded material.
They work similar in idea to rotary pipe cutters, in how they cut a little bit at a time. There’s a leverage multiplier such that the handles spread really wide to close the jaws a small amount.
I don’t think ratcheting bolt cutters would necessarily work better than standard ones – I guess it might be related to the type of material being cut.
For really hard materials, I don’t think bolt cutters cut them all the way. The force response isn’t exactly linear, as some of the effort involved imparts stress and pressure on the material. As soon as a cut begins, a lot of the stored energy will be relieved as the material splits itself apart.
Think about standing on an aluminum beverage can, which you might have done when younger. It’ll hold your weight until someone flicks it to create a localized weakness. Don’t try this at home by the way. Once that initial weakness is there, the can collapses instantly under your weight.
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Using bolt cutters in hard materials is usually a *grunt grunt grunt SNAP* process when cutting harder materials. Cutting PVC, branched, or wire cable is different and more linear. It’s more *squeeze, cut*, *squeeze, cut*, *squeeze, cut*, instead of *squeeze squeeze squeeze cut.*
Here’s a pretty standard ratcheting PVC cutter (Tekton branded), and there are a bunch more with similar designs over at Amazon.
I’m not saying that ratcheting bolt cutters would be impossible, but I can’t imagine a design that would be practical. The mechanism would have to serve as a force accumulator, as opposed to an incremental width advancer, for lack of a better description.
I suppose that it would be possible. Ratcheting bolt cutters would be say 14″ or 18″ in length, and with a ratcheting compound action mechanism. But do you know how beefy all of the components would have to be**? And how much pumping of the mechanism that would be required? I’d think that most users would simply opt for 24″ bolt cutters, longer ones even, or a powered cutting solution.
** Update: Nathan explains the same in his comment, but more eloquently: The gears/ratchet pawls [would] have to be strong enough to match the torque demand – and load – so they have to basically be stronger than the material being cut by significant margin. While possible – you’re now carrying around 100 lb+ bolt cutters that are hard to maneuver and place.
Maybe I’m being too skeptical here. What do you think? Are ratcheting bolt cutters a possibility?
David
First hit when googling for “ratcheting bolt cutters” is this link to Amazon:
http://www.amazon.com/MCC-Quality-Cutter-Ratchet-Capacity/dp/B008U80GBW
So they seem to exist already. Not sure of the value of the mechanism, but at least it has been tried.
David
Stuart
I wonder how I missed that. I saw a few ratcheting cable cutters, but hadn’t seen that bolt cutter. Still, I think it says something that the brand has a whole range of traditional bolt cutters and just one longer length (31″) ratcheting cutter.
fred
Thanks David
You learn or see something new every day!
I’m quite familiar with the MCC brand- having used and commented on ToolGuyd about their threaded rod wrenches and drivers. But I never saw these ratcheting bolt cutters.
Nathan
looking it over – it does have a slight capacity advantage over their basic 30 inch model – and that advantage comes at the ability to reset/reposition the handle so you can get another good press or 2 – while still working though the material. As I see it in the pictures – wish there was a better view of the end on the handles.
it’s not a significant advantage (a few 32nds with 36HRC rod) and it comes at quite the cost. I admit though it does seem like a decent piece of kit.
Kevin
For electrical there would be a need for a ratcheting cutter for 1/4 “ all thread or bolts. A single hand held tool not for pouches but the toolbox. Maybe something like “power dykes “ to cut black iron or rod then hand pressure snaps it off easily . Also , channel locks that ratchet closed not intended for cutting . When running 3/4 EMT or pipe with compression fittings . Reduces fatigue for all day everyday work. Vise grip handle is too short and flat jaws are preferred by many.
John
I use a cutting wheel in an angle grinder for the little bit of tough cutting I do but on occasion I have used normal bolt cutters and they work good enough. Why make them more complicated, it just drives the cost up.
Farid
One issue with cutting hard materials, if you start a cut and find out you can’t finish it, you will have to release the ratchet somehow, which usually means applying even more pressure on the handles until the ratchet moves slightly allowing the pawl some slack. I can imagine situation where the tool can get really stuck. We have a giant set of ratcheted cable crimps that got stuck because the wrong die size was selected. The crimp could not be completed without breaking the tool, and the ratcheted could not be released. We eventually got it loose by taking it apart, but it was not easy, and bit risky
Regarding your last addition about the ratcheting mechanism matching the material hardness… that is only partially true, as it depends where the mechanism is placed and the mechanical advantage it has. But, you are correct, to make make most practical and small, it has to be very strong.
firefly
This is an excellent point. It’s the kind of problem that often missed in engineering and got discover in real world use.
Jerry
I can see that they are available now, but for the price I may be better off just getting a larger set of standard bolt cutters for larger items, and some cutoff wheels for my cordless angle grinder for confined areas.
If they would be under $100, I’d be seriously thinking about it.
However, after a bit of poking around on Amazon, I see they offer hydraulic bolt cutters.
http://www.amazon.com/Hydraulic-Steel-Chain-Cutter-13ton/dp/B00S65H95K/
They are rated at 20MM cutting capacity and appear to work similarly to a hydraulic jack. Anyone ever use anything like that?
Toolfreak
Those work ok if you need the compact size, and powered hydraulic/pneumatic/electric cutters aren’t an option or out of the price range.
Otherwise, just going to the larger size bolt cutter with longer handles for more leverage works pretty well.
Jerry
What I’m looking for, is somewhat decent cutting capacity, in somewhat confined spaces. I’m needing capacity of at least 3/8 inch in medium hardness rod, but work in areas where long handles that open wide don’t fit really well. Also, this is an outdoor job around dry grass/weeds, so bolt cutters would be much Desiree over something that throws sparks. I ‘can’ make the bolt cutters I have work, but shorter ones that don’t require as much space to swing the handles would make the job much easier. They don’t have any specs on the overall length on the hydraulic ones. Do you have any idea on the overall length of these or any similar cutters?
Toolfreak
The ones I’ve seen are pretty compact, in the range of the 14-18″ bolt cutters.
Like I said, they are pretty much the best solution for a manually operated cutter in a confined space.
The issue is usually quality, most of these units are no-name made in China stuff, like Harbor Fright but not even Harbor Fright.
If you want to cut stuff but not spend $100+ on a cheap tool, I’d suggest a reciprocating saw with a carbide or diamond blade.
I’ve used my Bosch 12V Max compact recip saw with a Lenox diamond blade and it will go through the hardest hardened metal, with zero sparks. I use it for a LOT of other stuff too so it’s well worth the price compared to a specialty tool like a manual hydraulic bolt cutter, unless that is the only tool that will do the job.
Pete
Seems a like gear driven bolt cutter might be more effective. Dont know exactly how it would work but its certainly do-able. Make the gears compound the force rather than straight leverage.
Toolfreak
Ratcheting bolt cutters actually would be pretty good for cutting the hardened steel of bolts and locks, or at least it would let you rest your arms for a few moments without having to set up all over again, and you could pinch the jaws the rest of the way.
A ratcheting mechanism would actually be perfect on the foldable type of cutters, since usually not having enough leverage is what would cause you to need a ratcheting mechanism in the first place – either that or not having a sharp enough edge on the tool.
Cutters for hard wire with metal fibers or strands have a different jaw design, which actually cuts the wire so fast and clean that there would be no need for a ratcheting design if the edges were sharp. A ratcheting design might actually be more of a hindrance since you’d likely have to re-open the jaws and start the cut with the jaws open again.
AlphaFox
Add the ratcheting buckle loading belt around the handles and here You are 🙂
Paul
You made and interesting comment about a force accumulator opposed to an incremental width advancer. I am envisioning a mechanism that is almost hydraulic like a mini jack. You would essentially pump the jaw closed with every push of the handles. That would also address the safety concern with a not being able to release a ratchet that is too tight on hard materials.
Yes it would be heavier than a normal bolt cutter but maybe more compact because the need for mechanical advantage in the handles is not as necessary. It would still be lighter than a full jaws of life type cutter which is not human powered.
Mike
They exist, though I’ve never seen the actual bolt cutter variety in person. I do use the cable cutter configuration pretty frequently and it’s perfectly capable of slicing through anything a bolt cutter is capable of.
http://mmhtools.com/YQ-12B-hydraulic-bolt-cutter-p43.html
http://www.greenlee.com/products/CUTTER%2540c-CABLE%2540dHYDRAULIC.html?product_id=18387
Gabe
At my place of work, we regularly use hydraulic bolt cutters (all day, every day).
Not ratcheting, but it’s portable and suits our needs.
This is what we use:
http://www.wayfair.com/Monarch-Specialties-Inc.-Slide-End-Table-I-3204-I-3254-MNQ2057.html
The head of the cutter opens on a latch hinge to get around the bolt head. Snap the latch shut, then you pump the thing like mad until it cuts through the bolt. Has a jaw release lever on the side to open the jaw back to full open.
Jeremy
I’m thinking something small fit the plam of your hand has a gear drive in it to multiply the force has a 1/2 drive hole in the rear to use cordless impact or breaker bar or any other 1/2 tool if they can develop a gear mechanism in semi truck landing gear on the trailer that can lift 20 tons by easy had crank this should not be that hard
Roland
Bit late to the discussion here… but before I did too much more searching, your logic simply didn’t seem to hold up to me – if I can apply the amount of force to cut a bolt with normal bolt cutter, a ratchet to incrementally increase doesn’t seem that infeasible.
And… now that we are several years down the road from your post, it appears you should have patented the idea. Several exist. For a tool-guy, your armchair physics arguments seem to have been lacking… not as hard to make or as heavy as you thought. Expensive, yes. Worth it to some people for various reasons? Yes. Something I’ll consider? Nah, I’ll just keep making the guys responsible for checking my bolt-seals cut it with whatever tool they have.
https://www.westechrigging.com/bolt-cutter-klein-ratcheting.html
Stuart
You’re just reinforcing what I thought and said. This is a 31″ bolt cutter weighing 12 pounds. Do YOU have a better explanation as to why there aren’t 14″, 18″, or even 24″ ratcheting bolt cutters?
Chris L
I know this is an old post but wish I could even find a picture of the bolt cutters I have to give a link to it because I cant post a pic. One handle has a bar with groves on the top side and fit through a gear attached to the other handle. I would love to find out specs for them. I can not find any info whatsoever.