H. Akcay et Ca. Eckelman, A circular internal bond test for predicting the holding strength of furniture fasteners, FOREST PROD, 51(5), 2001, pp. 73-78
A circular internal bond (CIB) test was devised that provides a simple proc
edure for obtaining internal bond (IB) strength data that could be used as
an indicator of fastener-holding strength. The procedure consists of drilli
ng a hole two-thirds of the way through one face of a panel with a hole saw
, and then drilling a concurrent hole two-thirds of the way through the pan
el from the opposite face with a hole saw of a smaller diameter. The method
of the test consists of applying a load perpendicular to the face of the s
maller of the two disks cut into the face of the board until the ring of ma
terial holding the disk in place fails. CIB strength is computed as the ult
imate load divided by the difference in area of the two rings cut into the
faces of the board. This method of test yields IB strength values that are
only about two-thirds as great as those obtained by means of the convention
al IB test method. Thus, the CIB tests cannot be substituted on a one-on-on
e basis for the standard American Society for Testing and Materials IB test
. Values obtained with the CIB test proved to be slightly better predictors
of screw-holding strength than did those obtained by the standard method,
however. If this relationship also holds true for other fasteners, the CIB
test would provide a simple test method for obtaining board property data,
which should prove useful both for quality control and for product design.