Having looked at the various replies, my timidity in purchasing one of these jigs would appear justified. Yes I have watched the videos using most of these jigs you mention, yet they all neglect to include the fundamental principle rammed into my brain during my metalwork/woodwork classes, that to control the tool there must be a supporting bar close to the cutting face of the tool, minimising its distance as much as possible from the grinding face of the stone. This is so that the downward pressure at the end of the handle will prevent tip, which contributes to dig in.
Yes, with good strong pressure on the end of the handle, pivoting about a close set solid mounted tool tip, you could get away with a gourge or a chip lump flying from the stone, but if you study the arc of travel of the cutting face, with its handle end suspended in the jig pocket (the centre point of ark) the penetration is to 3/4 depth into the stone if handle remains in the fixed position, and the thought of this quick snatch (even on the bowl end tool is it called?) the pressure for cutting has to be so light, I guess to someone who has been using the jig for some time, they will know how much to apply, but for the rookie like me, well I guess I would be the first in hospital.
So, I guess after some verification of my fears I will be making a similar jig to Rhossydd when I get set up, in conjunction with a Wetstone as Procell suggested for the reasons given.
Oh, by the way, I think the video/write up said that the jig operator had cut away the guard so that full operation of the jig could be effected. As you will guess, I have been a safety rep in industry during my younger days in the Chemical Industry, a dangerous enough environment as it is to begin with. Cutting away safety gear from a machine is not a good idea as a press shop operator at Fords nearby where I live found to his dismay who cut off and removed the hand-guard plate from one of the press machines so he could turn out the body parts quicker, and distracted for just a split second got ALL his fingers chopped off as the press came down. Ignore safety and it will bite you in the arse.
