An apparatus for use in a linear variable differential transformer (LVDT) (105, 600), the apparatus comprising: a core extending along a first longitudinal axis and having a C-shaped cross section in a plane normal to the first longitudinal axis, the core having: 1) a core inner diameter defining an inner surface of the core and defining a central lumen extending along the first longitudinal axis, and 2) a core outer diameter defining an outer surface of the core; and, wherein the apparatus further comprises: a cylindrical rod extending along a second longitudinal axis and having a rod outer diameter defining an outer surface of the cylindrical rod, wherein the cylindrical rod is received in the central lumen of the core, wherein the C-shaped core includes a longitudinal gap which extends from a proximal end of the core to a distal end of the core, and wherein the C-shaped core includes a spot weld in direct contact with the core and the rod on the distal end of the longitudinal gap and a spot weld in direct contact with the core and the rod on the proximal end of the longitudinal gap, wherein the welds (620, 625) are configured to bond the core to the rod, such that the cylindrical rod is received in the central lumen of the core, and the first and second longitudinal axes align with one another. a core extending along a first longitudinal axis and having a C-shaped cross section in a plane normal to the first longitudinal axis, the core having: 1) a core inner diameter defining an inner surface of the core and defining a central lumen extending along the first longitudinal axis, and 2) a core outer diameter defining an outer surface of the core; and, 1) a core inner diameter defining an inner surface of the core and defining a central lumen extending along the first longitudinal axis, and 2) a core outer diameter defining an outer surface of the core; and, wherein the apparatus further comprises: a cylindrical rod extending along a second longitudinal axis and having a rod outer diameter defining an outer surface of the cylindrical rod, wherein the cylindrical rod is received in the central lumen of the core, wherein the C-shaped core includes a longitudinal gap which extends from a proximal end of the core to a distal end of the core, and wherein the C-shaped core includes a spot weld in direct contact with the core and the rod on the distal end of the longitudinal gap and a spot weld in direct contact with the core and the rod on the proximal end of the longitudinal gap, wherein the welds (620, 625) are configured to bond the core to the rod, such that the cylindrical rod is received in the central lumen of the core, and the first and second longitudinal axes align with one another. a cylindrical rod extending along a second longitudinal axis and having a rod outer diameter defining an outer surface of the cylindrical rod, wherein the cylindrical rod is received in the central lumen of the core, wherein the C-shaped core includes a longitudinal gap which extends from a proximal end of the core to a distal end of the core, and wherein the C-shaped core includes a spot weld in direct contact with the core and the rod on the distal end of the longitudinal gap and a spot weld in direct contact with the core and the rod on the proximal end of the longitudinal gap, wherein the welds (620, 625) are configured to bond the core to the rod, such that the cylindrical rod is received in the central lumen of the core, and the first and second longitudinal axes align with one another.