A gorgeous solution to a common problem… This mesmerizing mechanical vise adjusts its shape to hold oddly shaped items still without damaging them, using a design first patented more than a century ago. It can also turn inside-out.
Some things don’t fit neatly into a vise. It’s a problem that’s existed as long as humans have been trying to build and engineer things, and every backyard tinkerer has doubtless had to bodge together a solution for this kind of thing at one time or another. I know I sure have.
One very neat solution was put forth by Austrian/Hungarian inventor Paulin Paul Kunze in the early 1920s. Kunze envisaged a “fractal” vise using a number of freely rotating semi-circular grips, smaller ones nested within the larger ones, such that as the vise is tightened on an object, the grips are all able to rotate, molding themselves to the shape of the object and distributing pressure across it much more evenly than you can with a straight-jawed vise.
It did become a product at the time, sold by Mantle & Co – which later sold it to the United States Automatic Box Machinery Co, where it was rebranded as the Boston Automatic Vise. More recently, the idea has made its way into a bunch of 3D-printed DIY kits – and in 2021, YouTube channel Hand Tool Rescue reached 23 million viewers with the following restoration of a 1920s-era Mantle vise they dug up:
Rare Antique Fractal Vise [Restoration]
Not everyone is a vintage tool refurbisher or DIY enthusiast, of course, so it’s great to see a terrific old idea like this one getting another chance to make a splash thanks to “makers, creators, tinkerers and engineers” at UK company MetMo (Metal in Motion).
The MetMo team has created a compact version of Kunze’s fractal vise, with options for 3.2-inch (82-mm) or 1.2-inch (32 mm) clamping zones, a precision fine screw drive to perfectly lay the squeeze down with, and a grippy rubber baseplate.
Uniquely, this version lets you flip the fractal heads around, so you can invert the vise and use it (for example) to grip onto the inside of a tube or glass.
There are optional adapter plates you can use to bolt it to a bench, or a ball mount that clamps onto a bench and gives you many more flexible positioning options. You can get ’em in aluminum or brick-outhouse stainless steel, or if you’re desperate to throw money away, there’s also a stainless steel version plated in 24-carat gold.
MetMo Fractal Vice
MetMo has designed them – particularly the stainless models – to outlast the buyer as a tool that can be passed down a few generations. As such, each part is CNC-machined, and the Fractal Vise is designed to be taken apart and put back together so it can be customized, upgraded or repaired over time.
This might be a 1920s idea, but the pricing is extremely 2025. It starts at UK£149 (US$192) for the smallest aluminum vise, and goes up to UK£279 (US$360) for the long-travel stainless version before taking off into sillier territory for the gold-plated vises. These are early-bird discounts on Kickstarter, where MetMo is crowdfunding this product launch. So all normal crowdfunding cautions apply, and deliveries aren’t set to begin til January 2026.
Still, this is a super-charming design – part mechanical fidget toy, part seriously useful workshop tool – and those of us that wouldn’t shell out for this kind of thing can still enjoy the idea and the video!
We can also enjoy a second Hand Tool Rescue video… When Kunze patented this idea back in the 1920s, he thought it might also serve duty in anatomically-conforming chairs, which could use the same basic “fractal” mechanism to adapt to the shape of your butt. How did that go? Check it out below – jump to the 18-minute mark for the dramatic reveal!
The Fractal Chair
Source: MetMo