We have many different sizes of magnets with different thread sizes - both internal and external. Most of our magnets are made after the metric system (as used in Europe). However, we also made a list of calculated sizes from mm. to inches below, if you need to compare which American sizes comes closest to the metric thread sizes.
Here are the thread sizes according to the metric system first:
| Thread size | Increase in mm. | External thread diameter (Ø) | Internal thread diameter (Ø) |
| M2 | 0.40 | 2.0 | 1.6 |
| M3 | 0.50 | 3.0 | 2.5 |
| M4 | 0.70 | 4.0 | 3.3 |
| M5 | 0.80 | 5.0 | 4.2 |
| M6 | 1.00 | 6.0 | 5.0 |
| M7 | 1.00 | 7.0 | 6.0 |
| M8 | 1.25 | 8.0 | 6.8 |
| M10 | 1.50 | 10.0 | 8.5 |
| M12 | 1.75 | 12.0 | 10.2 |
As promised, here is a table with conversion from millimeters to inches if you are looking for measurements closer to American standards:
| Thread | Ext. thread | Converted to inches | Int. thread | Converted to inches |
| M2 | 2.0 | 0.079 | 1.6 | 0.063 |
| M3 | 3.0 | 0.118 | 2.5 | 0.098 |
| M4 | 4.0 | 0.157 | 3.3 | 0.130 |
| M5 | 5.0 | 0.197 | 4.2 | 0.165 |
| M6 | 6.0 | 0.236 | 5.0 | 0.197 |
| M7 | 7.0 | 0.276 | 6.0 | 0.236 |
| M8 | 8.0 | 0.315 | 6.8 | 0.268 |
| M10 | 10.0 | 0.394 | 8.5 | 0.335 |
| M12 | 12.0 | 0.472 | 10.2 | 0.402 |
The above conversion table to inches is made with a 3 decimal decrease. If you need more decimals, or if you need more thread sizes to convert, you can find a good converter on Google.
What are thread sizes used for?
You need thread sizes to find suitable screws and nuts. But also to know the size of the drill bit, if for example a magnet with external thread needs to catch a nut on the other side of a wooden board to make the wooden board magnetic (e.g. for a sign, a notice board or similar), or if you need to catch a magnet with internal thread with a bolt through a hole.
It is therefore important that you choose correctly from the start. Preparation is half the battle.
Please let us know if you need advice on choosing the right magnets for your project. We are available in customer service every weekday during opening hours.
