Unless otherwise specified, our tolerances on alnico material meet and often exceed International Magnetics Association (IMA, formerly MMPA) standards. For unfinished surfaces (as cast) the following tolerances apply:

0-1” ± .016
1-3” ± .031
3-5 ± .047
5-7” ± .062
7-9” ±.078
9-12” ± .094

Finished surfaces are normally ground to ± .005 (See MMPA standards for more details.)

Magnetizing is done after the magnet has been machined to the correct tolerances. Care should be taken when handling alnico material since it is brittle and can chip or break if dropped on a hard surface. Also, because it has a low resistance to demagnetization, it will lose power if it is stored improperly (poles repelling each other). For best results, store magnetized alnico so that pieces are attracting each other, or with a steel keeper.

Alnico is a very hard and brittle material and does not lend itself to conventional machining. The Magnet Source™ employs experienced machinists and the proper equipment to grind alnico to its required dimensions.