Crimping 68pin (HD68) Wire

[Ali via cctalk]

Hello All,Recently I tried making some custom SCSI cable. In the past I have 
successfully made my own 50pin SCSI and Floppy cables with out much issue. 
However, I am finding it almost impossible to crimp the HD68 connectors on the 
cable. I have even tried a vise grip and I still couldn't get it to crimp all 
the way down. Anybody with some advice? Is there a trick I am missing? TiA.