Is there a way to control "waste area" for blade start?

[tbeaulieu]

I'm trying to make a simple gasket using a drag knife. The tool path looks close to being perfect, except for the two center cutouts. The drag knife appears to be starting it's orientation of the cut outside the center cuts. The problem is that these cutouts are to be removed, so I'd want them to be sacrificial, without any extra cuts in the main body. In this specific situation I can live with it, but I'm curious for future situations.

[TReischl]

I may be totally off base here, but have you tried adding a "lead in"?

[tbeaulieu]

That’s what I was expecting, but that’s a tool path feature. This gadget creates the tool path from vectors.

[TReischl]

Sorry about that.

If it is working from vectors then what I suggest is that you create the lead in vector. Yea, I know, that is more work that just drawing a circle, but hey, it is what it is.

Evidently the gadget does not recognize inside v outside cuts? Or can that be done by specifying direction of cut?

[tbeaulieu]

Based on your suggestions, I experimented a little. I should work with this more in our physical world to see it in action. I can "trick" it by creating trail-offs inside the circle, but that only seems to help on the lead in (you can tell it to respect the path start). On the lead-out it still does what it wants.

I'm not sure why it does anything after the cut. Maybe so it knows the direction of the blade for the next cut? Also, I suspect the turn depth is what it will move to for the "leads". So, maybe it's ok to have a minimal trace where I don't instinctively want one? I suspect I need to experiment with how little of depth do I need to get it to bite and turn.

[MiloScott]

Some of the loops that look like overcuts or waste areas are just to move the spindle further, so the trailing point of the drag knife cuts to the corner, before turning. The point offset distance from center of the spindle to the knife point determines the amount of movement past the corner. Since the knife acts like a caster wheel, if you turned at the corner with the spindle centered, you would round off the corner with the knife point.