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Tubular cores, heater cores, cores, Swageable Cores, Swageable Insulators

USES:  MgO cores of this type are intended for bulk applications requiring only a tubular geometry with a heating element in the center.  The vast majority of commercial needs are met by powder filling applications, but special engineering requirements might make a preform technology desirable.

Description: MgO cores of this type are characterized by the single hole geometry, and the general scale of sizes from 4 mm to 14 mm.  The wall thickness is typically 15-20% and the default strength is typically similar to a cartridge wind core.  OZARK cannot distinguish your end use without your assistance, and the designation as a “tubular” core vs. any other type is only a superficial one.



It is not necessary to stipulate an OZARK grade.  OZARK uses high quality electrical grade fused MgO from two North American sources.  The minimum MgO content is 96.4% MgO with appropriate limits for impurities and magnetic iron.

For the purpose of finished part identification, OZARK part naming will use the prefix “T”.

Your certification paperwork may indicate one of the above designations, which are used internally to specify and engineer the perfect MgO grind and blend for your part.


The following are typical analyses or limits for powders used to produce MgO wind cores. All raw materials are high quality fused grain powders which are processed in-house to obtain optimum particle size distributions for end use.

Attention: The internal data of table “14” is corrupted!

Strength Toggle

Insulators are fired to uniform mechanical strengths which have been established for optimum handling and swaging characteristics for different applications. A true mechanical test does not exist to characterize “crushability”. A Modulus of Rupture measurement is normally provided for historical tracking purposes.  This test is a modified three point bending test performed according to ASTM standard E1652 Appendix 4 and has many limitations.  Please refer to our Technical Bulletin # (LINK AND REFERENCE HERE).