China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Round countersunk magnet is a magnet with countersunk holes (screw holes) on the surface of a round magnet, mainly made of NdFeB, widely used in machinery assembly, electronic equipment, household and other fields, the outer diameter size is mostly in the range of 8-25mm, today to introduce you to this size range of countersunk holes in the round magnet's surface magnetic strength and pull strength.
Below is the round shaped countersunk neodymium magnet, also called a countersunk magnet ring by some people.
Gauss value is an important index to measure the magnetic field strength of a magnet, which usually indicates the magnetic flux density at a certain point on the magnet surface. The magnetic grade of neodymium magnet (e.g. N35, N52) directly affects its Gauss value. Generally speaking, the higher the magnetic grade, the higher the magnetic field strength of neodymium magnet.
8mm diameter round countersunk hole neodymium magnets usually have a surface gauss value between 2700-3500 Gs. For example, with a thickness of 2mm, the Gauss value is 2700-2900 Gauss. With a thickness of 3mm, the gauss value is 2900-3100, and with a thickness of 4mm, about 3000-3300 gauss. Thicker gauss values will be larger.
The 10mm diameter countersunk hole circular magnet surface magnetic strength is generally in the range of 3300-4200 gauss, e.g. 3mm thickness surface magnetic flux density gauss is 3400-3700, 4mm thickness is 3800-4100 gauss, 5mm thickness is 3900-4200 gauss.
12mm outer diameter, 3mm thickness countersunk hole magnet ring, surface magnetic field strength of about 3500-3700 gauss. 12mm diameter, height 4.5mm countersunk hole round neodymium-iron-boron table magnetic data for 4100-4300 gauss.
15mm outer diameter, 3mm thick countersunk hole magnet ring has a surface magnetic field strength of about 3300-3700 gauss. 15mm diameter, 5mm high countersunk hole round rare-earth neodymium magnets have a surface magnetic data of about 3900-4300 gauss.
The surface magnetic field strength of a 20mm diameter, 4mm thick rare-earth countersunk circular magnet is about 3200-3500 gauss. 20mm diameter, 5.5mm high countersunk circular neodymium magnet has a surface magnetic field of about 3800-4300 gauss.
25mm diameter, 4mm thick round magnet with a countersunk hole typically has a surface magnetic field strength of 3100-3500 gauss. With a height of 6mm it is typically 3600-4000 gauss.
The following figure shows the diameter 8mm10mm12mm15mm20mm25mm countersunk hole round magnet pull strength size data, the front is N, the back is KG, Data is for reference only.
The above is about the NdFeB circular countersink magnet 8-25mm Gauss data and tension data introduction, there is a need to quote or custom neodymium countersink magnet can contact us.
Other common types of countersunk hole magnets;
Square countersunk hole magnets
Rectangular countersunk hole magnets
Other related countersunk hole magnets professional introduction;
Difference between Straight Hole and Countersunk Hole Magnets
Why ring neodymium magnets need to process countersunk hole shape?
Rectangular countersunk magnets basic size schematic drawing