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How to use a nut splitter

Updated: 23 October 2026

The nut in front of you is one you are willing to destroy. Seat the chisel on the centre of a flat, turn the screw until the nut cracks, and stop if the pin that keeps the chisel from spinning has sheared. This is that sequence. It is not a ranking of the sets on the [Nut splitter comparison](/hub/hand-tools/nut-splitter). The steps follow Wonkee Donkee’s how-to, where the guide screw often fails before the nut does. Peter F. updated this page on 23 October 2026. There was no lab cut. Wear eye protection before the first turn. A qualifying purchase can earn a commission at no extra cost to you.

The nut in front of you is one you are willing to destroy. Seat the chisel on the centre of a flat, turn the screw until the nut cracks, and stop if the pin that keeps the chisel from spinning has sheared.

Our top picks

BGS BGS 1812 nut splitter set

Best overall

BGS BGS 1812 nut splitter set
7.9/10about £18.11
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Hilka Hilka 12455002 nut splitter

Best value

Hilka Hilka 12455002 nut splitter
7.0/10about £12.56
View offer
QWORK QWORK 3-piece nut splitter set

Alternative

QWORK QWORK 3-piece nut splitter set
7.6/10about £15.45
View offer
On this page
  1. 1.Set the chisel back and seat it on a flat
  2. 2.Turn clockwise and stop at the crack
  3. 3.A second cut is a reposition, not more force
  4. 4.If the chisel spins or the frame bends

Set the chisel back and seat it on a flat

Wind the chisel back so the opening can pass over the nut. Wonkee Donkee’s first steps are that retraction, then a chisel square on the middle of a flat, not on a corner. A corner lets the edge skate, and the load goes into the guide screw. On a ring tool the far side of the ring is the anvil. Do not hunt for a separate pad the listing never shows. Hold the frame so it cannot twist. If the nut is rounded, one JEUCLEL review says flats have to be filed on first. If you cannot see a flat, this tool is the wrong next step. Oil on the stud will not stop a stud that spins on a ball joint. That case is on the nut splitter for seized nuts page.

Turn clockwise and stop at the crack

Turn the screw clockwise to drive the chisel, and anticlockwise to release it. Keep your other hand on the frame, not on the chisel. BGS and Hilka state 14 mm and 19 mm drives. JEUCLEL states a 19 mm spanner. A socket that almost fits will round the hex. Stop when the nut cracks. You do not have to cut it in half. One Hilka review says the thread was destroyed and the nut was not split, so a spared thread is a listing claim, not a result you can count on. Do not put an impact driver on the screw. A live view of Hilka B076FDG5BT on 22 October 2026 says that model is not for power tools. Reviewers on the BGS file greased the screw. The bullets do not say to, and grease does not harden the chisel.
BGS BGS 1812 nut splitter set

Testsieger

BGS BGS 1812 nut splitter set
7.9/10about £18.11
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A second cut is a reposition, not more force

If the nut has cracked and still will not turn, take the tool off and seat the chisel on the opposite flat. That second cut is a new position, not another half-turn in the same groove. Hi-Force and HTL, on hydraulic heads rather than these ASINs, warn that a second cut is when the blade can meet the bolt. If the first crack has let the nut spread, a socket may finish it. If the frame has gone oval, stop. Loading a bent frame harder locks the tool onto the fastener.

If the chisel spins or the frame bends

The grub screw in the side of the frame sits in a groove so the chisel cannot rotate. Wonkee Donkee describes it, and the amazon reviews say it shears. On QWORK the pin fails and the chisel spins. On BGS it is the cutting pin or the locating screw. On JEUCLEL the set screw snaps and the loop bends. When that pin has sheared, the tool is finished. Do not drill it out and carry on. If the nut is next to a fuel hose, a brake pipe or a steering joint you cannot see, a garage takes the joint. An angle grinder is a different harm, on the nut splitter or angle grinder page.

Common questions

Which way do I turn the screw?
Clockwise drives the chisel into the flat. Anticlockwise backs it off. That is the Wonkee Donkee direction for this type of tool. If you keep turning after the crack, the chisel can meet the stud. Do not add an impact driver if the frame has cocked.
Should the chisel sit on a flat or a corner?
On the centre of a flat. A corner lets the edge walk, and the load goes into the guide screw, which is the part these reviews say snaps. If no flat remains, one JEUCLEL review says flats have to be filed on first. If you cannot do that safely, the splitter is the wrong tool.
Do I have to cut the nut in half?
No. Stop at the crack. A split that lets a socket take over is a finish, which is what some BGS and Hilka reviewers describe. Cutting until the nut falls in two pieces is how the chisel reaches the thread the listing claims to spare.
Why is the chisel spinning?
The grub screw or roll pin that sits in the chisel groove has snapped, fallen out, or jumped the groove. Wonkee Donkee describes that screw as the part that stops rotation. QWORK, BGS, DASBET and JEUCLEL reviews all describe it failing, often on the first nut. Once it has failed, the tool is scrap. Tightening the set screw only helps before it shears.
Can I use a ratchet or an impact driver?
A ratchet or a spanner is appropriate if you can feel the crack and you stop there. An impact driver is not the method. Hilka’s live amazon.co.uk listing says that model is not for power tools. A DASBET reviewer used an impact driver after an adaptor snapped. That report sits next to tools that broke on first use.
When is the tool scrap, and when do I call a garage?
The tool is scrap when the guide screw has sheared, the chisel spins, the edge has chipped, or the frame is oval. Call a garage when the nut is on a brake hose, a fuel line, or a steering joint you cannot see. A driveway split is for a nut you can seat and a stud you can inspect afterwards.

Related pages

Nut splitter buying guide

Nut splitter

Best nut splitter: the review file, and who to skip

Nut splitter for seized nuts: exhaust, link, tow bar

Nut splitter or angle grinder: colder cut or sparks

Sources

Sources from the research digest, last checked on 22 October 2026.

  1. HSE, PUWER overview (retrieved 22.10.2026)
  2. HSE, INDG291 (retrieved 22.10.2026)
  3. Consumer Rights Act 2015, section 9 (retrieved 22.10.2026)
  4. GOV.UK, General Product Safety Regulations 2005 (retrieved 22.10.2026)
  5. GOV.UK, consumer product safety advice for staying safe (retrieved 22.10.2026)
  6. Wonkee Donkee, types of nut splitter (retrieved 22.10.2026)
  7. DIYWiki, threaded fasteners FAQ (retrieved 22.10.2026)
  8. Hilka nut splitter listing, amazon.co.uk (retrieved 22.10.2026)