ASTM B389-81 (2020) pdf free.Standard Test Method for Thermal Deflection Rate of Spiral and Helical Coils ofThermostat Metal.
Spiral Coils—The specimen holder for spiral coilsshall provide means for securely holding the coil. Althoughother means of support are possible, the holder or mountingarbor shall be preferably circular cross section whose diametershall be as large as possible without touching the inner turn ofthe coil under any conditions of test temperatures.The arborshall be slotted across its diameter and to a depth greater thanthe width of the specimen. The width of the slot shall beslightly narrower than the thickness of the specimen so that theinner tab will be a push or snug fit in the slot.The edges of theslot shall be sharp where it intersects the circumference of thearbor. The slot shall be so positioned in the arbor that the centerof rotation of the coil and the center of the arbor coincide. Helical Coils——The specimen holder for helical coilsshall provide means for securely holding the coil. Althoughother means of support are possible, the coil shall be held withits axis in a vertical position, the bottom end of the coil secured and the top end allowed to rotate freely with a temperahrchange. Preferably the end of the coil with the center tab snalbe considered the bottom and secured by clamping or pressfitting the tab into a slotted arbor similar to that described in6.4.1 for spiral coils. The depth of the slot shall be such that thefull height of the tab shall be held. If the coils do not have acenter tab, the arbor shall contain provisions for attaching thecoil with screws, rivets, or by welding. A transmission pointer can be affixed to the top end. The center line of the coil, thetransmission pointer， and the protractor shall coincide.
Deviations from these procedures of holding may be necessary when simulating the mounting used in the device forwhich the coil was designed, or in cases where coils are pressfitted on arbors. In these cases, the details of mounting shouldbe mutually agreed upon between the manufacturer and thepurchaser. Spiral Coils—To the outer end of the spiral coil shallbe attached a pointer that will transmit the rotation of the coil so that it can be read on the protractor. The pointer shall be oflightweight construction and attached to the coil by suitable means so that the movement of these portions of the coil thatdo not normally contribute to the movement of the coil with a temperature change shall not influence the rotation of thepointer. The pointer，when using the fixture shown in Fig. 1，shall be so positioned that its tip shall ride slightly above thedivisions of the protractor, but shall not touch the protractor at any time during the test. The pointer, when using the nxmreshown in Fig. 2, shall be of sufficient length so that the top may protrude from the bath when the coil is submerged. The pointerfor either method, shall be so positioned that it will be in linewith the radius of the protractor and the specimen.ASTM B389 pdf download.