roger lance
I watched the video of Frank Klausz where the Gramercy holdfast was slipping and then I watched the video that came up after that......it was of Frank in his new retirement shop and he was demonstrating making thru dovetails on his bench......he was setting the holdfast with a metal hammer......about mid video, he talks about his holdfast.....says that it is a Gramercy and that he "loves it".

There was no slipping in this second video.