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?
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.
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?