Watching Igor's video I noticed the system he uses to secure the blade with a wormscrew pressing downwards. I'm not sure that the force the wormscrew applies is enough to secure the blade.
As I noticed with my initial design, when I force the tool to make the cut, the blade retreats into the holder. I think I noticed something similar to Igor's video (compare 9:30 to 9:47).
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To remedy this I used the wedge type securing bolt that solved the problem for good.
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[/QUOte I have some of the old style tool holders ,,,lantern type,,, and several use cam lock to hold bits . I have used them and when tight they will not move if they do it tightens it tighter. Well I do have way to many tools of all kinds from 50 plus years of collecting and inherited from gran parents and friends. So many it's hard to sell them.