1. CASOMAN 17-piece — the set for most sheds
The CASOMAN covers the widest spread of the three, and that’s what puts it first. You get seventeen extractor sockets running 7mm up to 19mm plus the imperial (SAE, the inch sizes) equivalents from 1/4 inch to 3/4 inch, so whatever’s seized on the mower, the trailer or the old gate hinge, there’s a socket close enough to bite it. Inside each one are reverse-spiral flutes — angled teeth that dig into a rounded head as you turn it back off, gripping harder the more the bolt fights you.
It runs a 3/8-inch drive, the square hole the ratchet or breaker bar plugs into, which is the sweet spot for stuck fasteners: big enough to take real force, and it clips straight onto an impact wrench for the ones that won’t move by hand. The sockets are drop-forged chrome-moly — Cr-Mo, the tougher alloy used for impact sockets — with a black phosphate finish that shrugs off the surface rust these things live around. A drill adapter and a size-up adapter round out the case. It’s not the cheapest kit here and it’s not a trade name, but for the bolts a home shed rounds off, it’s the one we’d reach for first. (Joel: half the fixtures in the Traralgon place fought me on the way out — this is the spread I wish I’d had in the drawer.)
2. GEARWRENCH 86170 Bolt Biter — the one built to last
If you’d rather buy once, the GEARWRENCH is the best-made set here. It’s a reputable brand, and the Bolt Biter sockets carry a torsion zone — a section engineered to twist slightly under load instead of snapping, which is what usually kills a cheap extractor the first time it meets an impact wrench. A tapered mouth helps each socket seat down onto a chewed head, and they’re bi-directional, so the same socket that backs a ruined bolt out can nip a fresh one up. Each is dual-sized to fit both metric and SAE, and it’s chrome-moly like the CASOMAN. Where the import kits stop at a one-year warranty, GEARWRENCH backs these for life — the cover you’d want on the set you buy to keep.
The reason it sits second is the drive. It’s a 1/4-inch drive, eight-piece set aimed at smaller fasteners and tight spots — spark plugs, brackets and trim bolts, not a rusted 17mm suspension bolt. For fiddly work in a cramped engine bay it’s the nicest to use here, and the build should outlast the others by a wide margin. It just covers less, and it’s the dearest of the three. (Matt: I’d own this and the CASOMAN and stop pretending I won’t strip a bolt again — the torsion zone is the bit you’re paying for, and it earns its keep on a tool that only comes out when something’s already gone wrong.)
3. MIXPOWER 13-piece — the one for the glovebox
If a rounded bolt is a once-a-year problem, the MIXPOWER does the same trick for the least money. It’s a 3/8-inch drive set like the CASOMAN, with the same reverse-spiral flutes and the same chrome-moly under a black phosphate finish — thirteen sockets instead of seventeen, covering 8mm to 19mm and the SAE sizes alongside. There’s a knockout pin for punching a snapped-off stud back out of the socket, and a drill adapter in the case.
What you give up against the CASOMAN is the bottom of the size range and a bit of finish quality — this is the one most likely to look tired after a few hard jobs. But the flutes bite the same way, and for a glovebox or a rarely-opened drawer, thirteen sizes covers the fasteners most people ever round off. If you can’t picture reaching for an extractor set more than a handful of times, don’t spend up — this is enough. (Joel: not every tool needs to be the good one. For a bolt you’ll fight twice a year, a cheap set that works beats an expensive one that just sits in the drawer.)
How to get a seized bolt moving
An extractor only works if you set it up right. Undo direction is anticlockwise, so the flutes tighten their grip as you turn — the harder the bolt resists, the deeper they dig. Give a rusted fastener a soak in penetrating oil first and a few minutes to work; the socket does the gripping, but the oil does half the freeing. Seat the socket square and tap it down onto the head with a hammer so the teeth bite before you load it up. Take the first turn slow on a hand ratchet or a breaker bar (a long bar that doesn’t ratchet, so you get more turning force) rather than hitting it straight off with an impact wrench, especially on the budget sets — once it’s moving, then bring the rattle gun in. And know when to stop: if a head is sheared dead flat, an extractor socket has nothing to grab, and you’re into drilling it out.
The CASOMAN and the MIXPOWER are budget kits, and each carries a one-year quality warranty from the maker against a socket that fails or turns up faulty. The GEARWRENCH sits apart: its Bolt Biter sockets carry the maker’s lifetime warranty, which attaches when you buy through an authorised seller — so check who’s selling before you count on it. On top of any maker’s cover, Australian Consumer Law may also entitle you to a repair, replacement or refund if a tool isn’t of acceptable quality, whoever sold it.
The verdict
You’ll strip the odd bolt and want one set that covers it: the CASOMAN 17-piece. The widest size spread here, a 3/8-inch drive that takes real force and an impact wrench, and a build tough enough for the rust these live around. Not the cheapest and not a trade name, but the one that’ll have the right socket when you need it.
You’d rather buy the good one, or you’re working in tight spots: the GEARWRENCH 86170 Bolt Biter. The torsion zone and tapered sockets make it the toughest-built set here and the nicest in a cramped engine bay, and it’s the only one warranted for life — marked down only because the 1/4-inch drive and eight pieces cover less, at the highest price.
A stuck bolt is a once-in-a-blue-moon job: the MIXPOWER 13-piece. Same flutes, same drive, fewer sizes and a thinner finish — plenty for a glovebox and the handful of times most people ever need it, at the lowest outlay.
All three bite a rounded head loose. Pick on how often you’ll need one — a regular risk in your shed, or a rescue tool you hope stays in the drawer.
