Product Details
Thin steel sheet is the hardest material to lift magnetically. Below 5 mm, a conventional two-pole lifter struggles: the sheet absorbs only a fraction of the magnetic field, the ON lever fights you, and the sheet sags away from the magnet at the edges. The PML Double Circuit Magnetic Lifter was engineered specifically to solve this problem.
Instead of the two poles found in conventional lifters, it uses a four-pole, double magnetic circuit built around high-grade NdFeB (rare earth) magnets. The double circuit spreads the magnetic force across a larger contact area and uses it more uniformly — so thin sheets under 5 mm are held securely, and the ON–OFF lever turns with noticeably less effort, something a single-circuit lifter simply cannot offer in thin-sheet work.
Lifting Large or Long Sheets
Thin sheet sags under its own weight, and sag creates air gaps that weaken any magnet's grip. For longer or wider sheets, the correct practice is to distribute the load: hang multiple Double Circuit lifters from a spreader beam, spaced along the sheet to counter waviness and sag. The same multi-lifter arrangement handles large steel plates, and the lifter also serves for connecting MS plates during handling operations.
Compact, lightweight and entirely self-contained, the Double Circuit lifter works as a hoisting device across industrial plants, fabrication shops, warehouses, docks and the transportation industry — improving both working conditions and working efficiency wherever sheet is moved.
Key Features
- Purpose-Built for Thin Sheet
Lifts thin plates up to 5 mm thick — the application where conventional two-pole lifters fall short.
- Double Circuit, Four-Pole Design
Uniform magnetic force over a larger contact area, for a stronger grip and greater operational safety.
- Effortless, Lockable ON/OFF Lever
Noticeably reduced lever effort, with a locking system that prevents accidental switch-off.
- 2.5× Factor of Safety
Meets all safety standards for under-the-hook devices — verified by test certificates from government-approved third-party testing.
- Zero Electricity, Zero Upkeep
Permanent magnets need no power supply, no maintenance and carry no operating cost.
- Built to Last
Forged hook for high mechanical strength; compact, lightweight and rugged — and no damage to the work-piece being lifted.
What This Means for Your Operation
- One operator can move large, heavy work-pieces safely and single-handedly
- No slings or clamps to rig — lifting magnets save labour and time, improving productivity
- Space is used more effectively: no need to gauge and increase stacking height
Construction & Operation
The lifter generates its magnetic field path through permanently magnetised NdFeB material — turning the lever manually switches the magnetic path ON or OFF, and a hook on top takes the crane connection. Because the magnets are permanent, holding force costs nothing to maintain and cannot be lost to a power failure.
Operating Instructions
- Keep both the work-piece surface and the magnet pole faces clean and smooth. Ground or machined surfaces are ideal, but a clean, sufficiently flat ferrous surface or casting is acceptable — the goal is full magnetic contact.
- Ensure there is no air gap or inclusion between the magnet poles and the job surface.
- Place the magnet on the ferrous surface, unlock the lever by pulling it out, turn it to ON, and release to lock. Reverse the procedure for OFF. (Never attempt to switch ON against a wooden or non-magnetic surface — the lever will not operate.)
- Move the load smoothly; avoid shocks and collisions.
- To set the load down, turn the lever to OFF only after the load is resting in a balanced position.
When Not in Use
- Apply grease or oil to the magnetic pole faces to prevent rusting.
- Rest the lifter on a thick wooden plank to protect the pole faces from damage and scratches.
Safety Instructions
- Always place the magnet on the ferrous surface in the OFF position before switching ON.
- Position the magnet over the load's centre of gravity before lifting.
- Keep all personnel out of the immediate danger zone while the load is in motion.
- Confirm the lever is OFF only after the load rests securely in a balanced position.
Understanding Real-World Lifting Capacity
A magnetic lifter's rated capacity assumes ideal conditions, and honesty about the physics keeps your team safe. Magnetic force flows as lines from the north to the south pole, and anything that restricts that flow reduces lifting ability. Four factors matter:
Load surface condition. Magnetic lines of force do not travel well through air — they need iron. Paper, dirt, rust, paint, scale or a rough surface finish all act like an air gap between magnet and load, cutting lifting capacity.
Load length and width. As a load gets longer or wider it stops lying flat and droops at the edges. That sag opens an air gap, and capacity falls.
Load thickness. The thicker the load, the more magnetic lines of force it can carry — up to the magnet's full capacity. Thin material carries fewer lines of force, so every magnet is rated for a minimum load thickness; below it, capacity derates. As a rule of thumb, the load should be thicker than the width of one magnet pole.
Load alloy. Low-carbon steels such as soft iron and mild steel conduct magnetic force almost as well as pure iron. Alloys containing non-magnetic elements conduct it poorly — a stainless alloy like ANSI 1020 is nearly as poor a conductor of magnetic force as air. Use the reduction factors below for materials other than AISI 1020 steel:
| Materials | Reduction Factors |
| Cast Steel | 0.90 |
| 3% Silicon Steel | 0.80 |
| AISI 1995 Steel | 0.70 |
| 416 Stainless Steel | 0.50 |
| Cast Iron (Non-chilled) | 0.45 |
| Pure Nickel | 0.10 |
Frequently Asked Questions
Why do I need a double circuit lifter for thin sheets?
Sheet under 5 mm is too thin to absorb a conventional lifter's full magnetic field, so grip suffers and the ON lever becomes very hard to turn. The four-pole double circuit spreads the field across a larger contact area, holding thin sheet securely with an easy lever action.
Can I lift a large sheet with a single lifter?
No — long or wide thin sheet sags at the edges, which opens air gaps and weakens the grip. Hang multiple Double Circuit lifters from a spreader beam, spaced along the sheet.
What happens if the power fails mid-lift?
Nothing. The lifter uses permanent NdFeB magnets and consumes no electricity at all — the hold cannot be lost to a power failure.
Will it mark or damage the sheet?
No. The magnetic grip leaves no damage on the work-piece being lifted.
Why Buy From PML
- 65+ years of magnetic expertise — Permanent Magnets Ltd has designed and manufactured magnetic products for 65+ years, and our consumer range is built to the same engineering standards we supply to global industrial leaders.
- Made and tested in-house — magnets, assemblies and finished products are manufactured and quality-checked at our own facilities, so every unit performs to its stated specification.
- Honest specifications — the ratings you read on this page are the ratings you get. If your application needs a different size or strength, our engineers will tell you exactly what works — and what won't.
- Support from real engineers — from product selection to after-sales, your questions are answered by the team that builds the product.
Need help choosing, or a custom specification? Enquire now and our engineering team will guide you to the right solution.