Magnet how to make plastic coated neodymium magnets
A pot magnet is a permanent magnet encased in a steel shell, which is sometimes called a pot, hence the name 'pot' magnet. 

A permanent magnet emits a magnetic field without the need for any electricity
The steel shell helps the pot magnet by increasing its holding power and providing the magnet with added strength and stability. 

Magnet
A pot magnet's magnetic face is only exposed on one side of the steel pot.
The north pole of a pot magnet is in the centre of the magnet, with the south pole around the outside edge.
 
The configuration of the magnetic poles creates a closed circuit when the magnet is attached to a ferromagnetic material, providing a stronger hold. A closed circuit is where the magnetic field is trapped within the ferromagnetic material when it becomes attached to the magnet.
 
This type of magnetisation does lead to the magnetic field being strong, but not far reaching, as the lines only run parallel to the magnet. Therefore, the pot magnet can only attract ferromagnetic materials when they are very close to the magnetic face.
 
Steel shell on a pot magnet
The steel shell is a casing for the magnet and protects it from any chipping or cracking from contact with a hard surface.
 
The steel pot provides strength for the magnet, which would otherwise be very brittle, and allows threaded holes and studs to be inserted.
 
The steel shell helps the magnetic field become up to thirty two times stronger than other magnets by concentrating it to only one magnetic face. This means it can hold large objects such as supermarket signs from a ceiling without any additional support.
 
Some varieties of pot magnet can also be encased in a brass or plastic shell. The brass and plastic provide the magnet with a non-ferromagnetic shell which increases the magnetic field when a pot magnet is not supplied with a spacer. This only occurs in American pot magnets, as brass or plastic shells are not currently available in this country.
 
Pot magnet spacer
A spacer acts as a barrier in-between the magnet and the steel shell to avoid any demagnetising effects the steel may have on the magnet.
 
A spacer in a pot magnet can either be made of brass or plastic. 
Rubber cap and rubber coating on a pot magnet
Pot magnets can have a rubber coating on top of their steel shell which allows them to be used on surfaces where the user does not want the magnet to scratch, such as on a car roof. 
 
If the pot magnet does not have a rubber coating, there is the option to buy a rubber cap which is easy to press onto the magnet and to remove.
 
The rubber provides the pot magnet with friction which allows the magnet to be clamped on vertical surfaces so they will not easily slide off. However, the rubber cap or rubber coating on a pot magnet creates an air gap meaning the holding capabilities of the magnet can be reduced.

There are five forms of pot magnet: bi-pole, countersunk, through hole, internal threaded, and stud.
Pot magnets are often used as magnetic bases and magnetic holders for large supermarket ceiling signs.
GME Neodymium Pot Magnets compliment our Alnico Pot Magnets by delivering large holding powers in small packages. These magnets are designed to be "Low Profile," but still incorporate a tapped hole in the back wall for mounting.
The Neodymium Pot Magnets not only have a potent attraction while in direct contact with a work piece, but they also have excellent field projection capabilities.

NEODYMIUM with higher operating Temperatures and Intrinsic Coercive Forces are available in these Pot Magnets. Samarium Cobalt and Stainless shells and shields are also manufactured. The all Stainless Pot Magnets, for both Alnico and Neodymium, are a Level I or II food grade unit.
All GME Pot Magnets are Centerless Ground after pressing to +0.001″ / -0.000″. The standard tolerance on the length is +/-0.015″. Tighter tolerances are available upon request.

Options
Various Tap Styles and Tap Depths.
Insulated (Brass Sleeved).
Shoulders and Machined Features on shell.
Protruding Pot Magnets.
Metric and Custom Sizes
What are pot magnets used to?
 Exhibition display signs
Countersunk pot magnets can be used to attach an exhibition display sign to a stand for marketing purposes, e.g. at a trade show.
 Magnetic bases
Deep internal threaded pot magnets can be used as a magnetic base for gauges e.g. an articulated gauging arm. An articulated gauging arm is used to precisely position objects within metrology (the science of measurement).
  
Tow lights
Through hole pot magnets can be attached to the bottom of a tow light to enable the user to attach the tow light to the car to warn other road users that their car has broken down.
 
For more information, please refer to greatmagtech.en.made-in-china.com or greatmagtech.en.made-in-china.com