PITTSBURGH JENNMAR's latest offering is its INSTaL HT (high tension) system featuring J1M and J8M expansion shells. The key change in the new design is a three-prong configuration that provides more surface area contact than the older four-pronged expansion shell. That means that J1M and J8M shells set more quickly and with less torque. The three-pronged design eliminates the use of heavy support nuts, improving the installed torque-tension relationship and eliminating any distortion or twisting of the expansion shells. They are suitable for use with or without resin.
The new J1M shell comes in 5/8-in. diameter for a 1-in. diameter drillhole. The J8M shell in -in and 7/8-in. diameters is suitable for 1-3/8-in. drillholes. Both meet current F432-95 rock and roof bolt specifications including the thread compression test.
For all your bolting needs see www.jennmar.com.