Metmo Fractal Vise 32 and Dual M18 Battery Adapter: Two TikTok Finds Put to Work

Introduction

Every so often, a tool shows up in our feed that we just have to buy and test for ourselves. This time it was a pair of items that kept getting tagged in our direction: a fractal vise that conforms to nearly any shape, and a dual battery adapter that promises both more amp hours and more power. Both come from very different corners of the internet, but they share one thing in common: they looked too interesting to ignore. So we bought both, put them through real work, and measured what they could actually do.

Metmo Fractal Vise 32: What It Is

The Metmo Fractal Vise 32 is a compact clamping tool with a design that lets its jaws conform to irregular shapes. We bought the black version with polished stainless jaws, which costs less than the all-polished stainless model while doing the same job. We also picked up a base that allows the vise to be screwed into a tabletop. In total, we paid $240 for the vise plus the base.

Metmo appears to be a company based in Yorkshire, England, that makes precision metal tools and puzzles. The package shipped from there, and some parts are cited as being from the UK and Netherlands. The fit and finish are serious: the hard coat anodized body, precision ground stainless surfaces, and tumbled edges show careful machine work. The custom Acme-style thread and knurled stainless handle with brass ends feel more refined than our usual shop tools.

When it arrives, it looks smaller than it does in product photos. That is worth knowing before you buy. You can mount two side by side on the same base plate to enlarge the clamping area, but at that point the cost approaches that of a full-size daily use vise.

Clamping Performance and Limits

In practice, the fractal vise does what its design suggests. It clamps awkward shapes well, from round parts to forged pieces with uneven surfaces. We used it as a drill press vise for fabrication work, and it held parts in place for drilling and grinding without complaint. You do not need to position parts perfectly, which is a real time saver.

It did struggle with thin, flat material. The sliding crescent jaws do not get enough purchase to hold a thin piece down against drilling pressure. A traditional vise handles that better because you can add blocking on the flat surface. The fractal vise also has a drive screw down the center, so drilling through a thin flat piece means you will eventually drill into the vise itself.

Tapered parts are another weak spot. Something that is straight-up tapered will slowly pinch and push out of the vise like a wedge. But for threaded pieces and bolts, it is excellent. Normally we wrap threads in a shop rag to protect them, which can let the part spin or become a hazard at high rpm. This vise spreads the load around the whole diameter, holding threads securely without developing flat spots, even on soft nickel-plated brass.

We measured the clamping force at 205 to 215 kg, or about 460 lb, by hand. That is more than expected, though about half of what a drill press vise can do. Using a drill with the clutch set to 10 on an M18 driver, it delivered 250 kg or 550 lb. Letting it run at full power produced up to 570 kg, or 1,250 lb of clamping, which held parts that would otherwise pry out easily. For context, a lower end hand clamp does about 75 kg, and a higher end version of that style reaches about 250 kg at its max.

The build quality held up well after use. The surfaces that need hardness have it, and the ones that do not are left softer. The jaws usually settle into a natural position without fiddling, and the thread has not collected shavings in a noticeable way. The little handle can thread off even with Loctite on it, but the drive screw is large enough that it is not likely to break by hand.

Would we buy it again? It is not cheap, and we wish there was a less fancy version for rougher work. But after a month or two on the tinker table, it has proven genuinely useful. If someone offered us $240 to take it off our hands, we would probably say no.

Dual M18 Battery Adapter: What It Promises

The second item is a dual M18 battery adapter that turns one tool into a two-battery setup. The marketing suggests it increases both run time and power. We found a few versions on the seller page and bought a couple to test.

The adapter does not actually make the tool run at 36 volts, but it does double the cells you have on tap. It is not meant for every tool, but in the video that got us tagged, it was used with an M18 high torque impact wrench. That tool does crave large batteries, so we wanted to see what doubling up standard packs would do.

We tested it with two XC5.0 packs and got 922 ft lbs of torque, up from 789 ft lbs with a single XC5.0 directly on the tool. That is close to what a 6 amp hour stacked Forge pack delivers, though not quite across the whole curve. Using DeWalt batteries, which have fewer built-in limits, we got 978 ft lbs. Two 12 amp hour Forge packs, about $500 worth of batteries on a $27 adapter, produced 985 ft lbs. It seems tapped out around that point.

Inside the Adapter and Real-World Data

Opening the adapter reveals a simple bus bar board. There is no regulation, no thinking, and no capacitance. It is just live wiring connecting the two packs together. That means you should not put a low charge pack next to a full pack on the same adapter, because they will try to equalize voltage with as much current as they can. It might work as a way to jump-start an old battery that is not charging, but it is not a controlled process.

We strapped batteries onto our test rig to get precise data. With a single XC5.0 under a high load request, we saw about 54 average amps, 875 W, and an average operating voltage of 16.4 V. With the dual adapter under the same request, we saw over a kilowatt on average, up from 875 W, and 2.9 Wh of energy during the same trigger duration. The higher operating voltage means the high draw request cannot sag the voltage down as far, and this effect becomes more pronounced the longer the tool runs.

That said, a single 8 amp hour Forge pack still beats the dual adapter. It delivers about 1,070 W instead of 1,000 W, and 3.07 Wh instead of 2.9 Wh. So the adapter does increase power if you only have standard packs, but some single packs will outright beat it. It is good for seeing spikes, like hitting a knot with a circular saw, and it can increase both power and run time in theory.

Does it represent savings? Sort of. If you already have two XC5.0 packs from kits, a $27 adapter in a drawer might get you similar Forge pack performance in a bind without buying a $200 battery. It is not complex, well regulated, or pulling from the packs independently. It is clumsy and heavy, but it is also a striking setup that gets 10 amp hours out of tools that drain batteries fast.

Overall Buying Advice

These two tools serve very different purposes. The fractal vise is a utility tool that earns its place on the bench for anyone who works with odd-shaped parts, threads, or delicate materials. It is expensive, but the build quality and clamping performance justify the cost for serious users. The dual battery adapter is more of a novelty that has real uses in a bind, especially if you already own standard packs and want a boost without buying a premium battery. It is not a replacement for a good high-capacity pack, but it is a fun and occasionally useful addition.

Conclusion

Both tools did better than we expected. The fractal vise wins on utility, earning regular use in our shop for fabrication work and thread holding. The dual battery adapter wins on spectacle, delivering a noticeable power bump with standard packs and a very memorable look on the tool. If you work with irregular parts and threads, the vise is worth the money. If you want extra runtime and occasional power spikes from batteries you already own, the adapter is a cheap experiment worth trying.