Strong Magnet For Magnet Fishing (60kg Pull) - £17.00
Strong Magnet For Magnet Fishing (60kg Pull)
PLEASE READ ALL HEALTH AND SAFETY DOCUMENTS BEFORE YOU USE YOUR MAGNETS (CLICK HERE TO DOWNLOAD)
Neodymium Magnets (NdFeB) are some of the most powerful magnets which can be bought on the open market today. They are made up of Neodymium, Iron and Boron. Neodymium magnets can create a force of up to 850 times there own weight.
Ideal For Magnet Fishing In -
Used for -
- Metal Detecting
Purpose of this document
To enable safe handing of any powerful magnet (Neodymium Iron Boron/NdFeB, Samarium Cobalt/SmCo, Ferrite/Ceramic and Alnico) and to educate users about the dangers associated with these magnets. The information can also be applied to any powerful magnetic system or magnetic assembly.
Neodymium/NdFeB magnets are the most powerful type of magnets commercially available today. They are available in power grades from N27 (powerful) to N52 (extremely powerful). Neodymium magnets and magnetic assemblies have extraordinary magnetic power and are used for applications that require the highest possible performance from the smallest possible volume. They can be dangerous to handle and use.
Although this text primarily refers to Neodymium/NdFeB magnets, the contents are equally applicable to any SmCo, Ferrite or Alnico magnet and any magnetic assembly deemed powerful enough to pose a potential Health and Safety risk. These other magnets, although weaker than NdFeB, can be as powerful as NdFeB if of big enough size. Where the word ‘Neodymium” or “NdFeB” occurs, it can generally be interchanged with “SmCo”, “Ferrite”, “Alnico” or “magnet assembly”.
- Risk Of Injury
A neodymium magnet is not dangerous unless it is placed within reach of another magnet, a strong electromagnetic field or a ferromagnetic (ferrous) surface.
Larger neodymium magnets can attract each other from surprisingly large distances (in some cases 500mm) and, if they are free to move towards each other, incredible forces are unleashed.
A combination of massively increasing attraction, a sizable mass, sharp comers and high velocity can, in the worst case, sever fingers from a hand.
Never underestimate the strength of magnets — they can be (and often are) more powerful than you think they are.
Magnets are hard and brittle. They can break, crack, chip or shatter if allowed to fly together or mechanically crushed.
The following assessments of risk related to the hazard of fingers being trapped between two magnets. Two magnets attracting each other have TWICE the attractive power of one magnet attracting a steel part.
Small Neodymium magnets (<1 cm3) are fascinating and can surprise users with their ability to attract through relatively large air gaps and can nip the skin on fingers. They cannot cause any real injury. The biggest danger of these magnets is if they are swallowed and cannot pass through the digestive system because of internal attraction. Swelling and considerable pain will soon follow and surgery will be needed to remove them.
Medium Neodymium magnets (1 cm3 — 12.5 cm3) offer substantially higher forces and can cause minor injuries to fingers. They can cause trapping injuries such as blood blisters and cuts to the skin.
Large Neodymium magnets (12.5 cm3 — 50 cm3) offer high forces and manual separation of two magnets should not be attempted. They can cause chunks of skin to be severed from a hand or cuts and bruises.
Very Large Neodymium magnets (>50 cm3) offer forces that make them impossible to separate manually unless special tools are used. As the volume increases the clamping forces increase proportionately. Magnets in excess of 125 cm3 can sever fingers if two attract each other and a finger is caught in-between. These magnets should be classed as very dangerous.
- Magnetic Forces
All magnets unleash their maximum attractive force when in direct contact (no air gap) with another magnet. They offer half this force when in direct contact with a ferrous or steel surface.
If the steel or ferrous part is thin in cross-section and cannot absorb all of the magnet’s magnetic field then the hold is reduced proportionately to the cross-sectional thickness of the surface. 2
If the surface is made of steel and is flat, clean and thick in cross-section, then optimum pull forces are realised.
Example: A powerful neodymium magnet may exert only 25 kg of force on a 1mm thick piece of sheet metal and yet 250 kg of force on a piece of steel plate 10mm+ thick. The same magnet would exert a force of500 kg on a matching magnet of opposite polarity.
If an air gap is introduced which prevents direct contact between the magnet and the part that it is attracted to, then the attractive force is less. A non-magnetic material between magnet and steel creates an ‘effective air gap’. =
As the gap thickness increases, then the attractive force decreases dramatically. Conversely, as the gap decreases, the attractive force increases dramatically.
- Inverse Square Law Relationship
The relationship between magnetic attraction and ‘air gap’ follows an inverse square law relationship which means that the level of attraction falls away dramatically as air gaps are introduced.
An air gap is any non-magnetic material including for example paint, plastic, wood or even a finger.
Two large magnets may offer an attractive force of 5 kg through a gap of 100mm, as they get slightly closer, this amount increases substantially.
If your hand was trapped in-between the two magnets, the force would start to compress your hand and as your hand got thinner and the magnets became closer together, the forces would then increase dramatically again causing further compressions and yet further increases in force. The scenario really is like having your hand in an engineer’s vice whilst a colleague tums the handle to crush your hand.
Once in this situation, there is no real way of releasing the hand from the magnets as the skin bulges around the magnets making sliding impossible and the forces are so high that only special equipment such as hydraulic clamps can pull them apart. This is extremely serious and must be prevented by a rigorous and well-rehearsed Health & Safety methodology and assessment.
- Safe Handling - Rigorous & Well Rehearsed Health & Safety Methodology
- Read all of this information thoroughly before handling the magnets; ensure that anyone coming into contact with the magnets has read and completely understood it.
- Workin a clear uncluttered area and evaluate it for possible hazards such as anything ferrous (ferromagnetic) or any other magnets. Do this before unpacking the magnets.
- Remove any magnets or ferrous objects from the working area AND create an exclusion zone of 2 metres all around the perimeter of the working area.
- If magnets have been supplied in individual containers, do not remove more that one magnet at a time unless special provisions have been made.
- Special provisions include wooden or rigid plastic partitions at least 50mm thick and 300mm high firmly fixed between two large magnets.
- Be aware that these magnets can do the most unexpected things:- they can attract each other from distances in excess of 500mm.‘ They can jump over or jump around undersized dividers or spacers that separate them. If in repulsion, they can flip over and pull to each other in attraction. Once they start travelling towards each other, the massively increasing forces can accelerate the magnets to very high speeds before impacting each other.
- Two magnets impacting in this manner will shatter or crack causing sharp fragments to fly off at high speeds in any direction.
- Safety goggles should always be worn to protect against this possibility.
- When handling large or very large Neodymium magnets, always rehearse every action to evaluate the risks. Create a risk assessment to eliminate any possible risk.
- Be very cautious; take excessive precautions. Two Very large magnets with a hand trapped in-between cannot be removed.
- Never underestimate the power of these magnets.
- If two magnets do accidentally get stuck together, then a non-magnetic fixture must be constructed which will firmly hold one magnet and slide the other one off by means of a screw jack, hydraulic ram or a long wooden hinged sweeper arm.
- it is 5 times easier to slide magnets apart than to try and pull them apart vertically.
- Always ensure that one magnet is firmly held and the other is at least 300mm away before attempting to recover one of the two magnets. Always move it away from the magnet and be aware that these magnets can easily ‘snap-back’ once separated.
- Never work near the magnets with steel tools such as spanners, wrenches or screwdrivers. A significant trapping hazard exists if fingers can be caught between a magnet and a heavy steel wrench. The level of attraction is directly related to the volume of steel contained within the tool. A tiny screwdriver will not experience such high forces because its small volume cannot carry much magnetism.
- If you do have to work close by, obtain non-magnetic stainless steel tools or firmly fix non-magnetic and non-compressible rigid spacers in place so that, if attraction occurs, the tools cannot get any closer than 50mm away. At this distance, crushing injuries are not possible.
- Remove watches and credit cards from operators as they will be permanently damaged by the fields from these magnets.
- Safe Handling - Rigorous & Well Rehearsed Health & Safety Methodology
- Do not allow the magnets to be near computers, monitors or magnetic media as the magnets will disrupt or damage them (within <2 metres).
- Do not allow any person with a heart pacemaker to get within 1 metre of the magnets.
- Do not allow any person with steel plates inserted in any part of the body to get within 300mm of the magnets.
- Do not use these magnets in explosive environments.
- Placing Very Large Magnets Onto A Thick Steel Plate
If you do need to mount a magnet onto a steel plate, do not attempt to simply drop the magnet in position, it could cause injury and will almost certainly cause cracking or chipping.
The following method should be used:-
Prepare 10 pieces of 1mm thick non magnetic stainless steel (304, 316 etc) each at least 200mm x 200mm (bigger if the magnet has a large area). One edge should be bent up at 90 degrees by 15mm fo create a handle.
Prepare 5 pieces of rigid plastic sheet each 10mm thick and the same 200 x 200mm size.
Stack them all on top of the steel, with the plastic on top and the stainless pieces on top of the steel surface. This stack will be 60mm tall. Carefully place the magnet centrally on the stack. Attraction will be felt but at manageable levels.
Maintaining the magnet’s central position, slide out the plastic spacers one at a time to that the magnet drops 10mm each time and then the stainleSs plates one at a time so that it drops in 1mm increments.
- Technical Support
If in doubt — please call +44 191 584 2709 - Email – firstname.lastname@example.org – Website ropeservicesuk.com