My machine has a three inch max depth of cut. I have some thoughts about the Z axis carriage and how the spindle motor is mounted to it. Theory, if the top of my table is at max depth, three inches from the Z axis carriage then the max depth is reduced by the thickness of the spoil board, correct?, does this make sense so far. Then if any of this is true then I should mount my permanent table surface at three inches plus whatever thickness I choose to use as a spoil board. Making the thickness of the spoil board my default thickness. Any comments, I have pondered this for a long time now. Is it rational????
I don't know what mill you have, but my head is movable, (given that I remember to lock it after I do move it) while the spindle only moves abut 1 3/4 inches. Yeah, if your head is semi-fixed, can't be moved easliy, that 's what I'd do. If you need three inches of movement, and can accommodate a piece of spoil, you still have three inches of movement.
I suspect we are talking about a CNC router here, since you didn't specify. Do you only have 3 inches of travel on the Z? If that's the case, then I would do as you described. I would set it up so the shortest tool bit would just penetrate the spoilboard surface at maximum Z extension.
Once again, I didn't add enough info. The machine I have is a K2CNC 2514 Gantry Router. There is only three inches of clearance between the gantry assembly and the table.
But I have thought it is lessened by any spoil board unless the table is mounted on a modified plane. I wish I could add photos, but.
That is correct. The only way to add clearance is to make taller gantry support arms, or lower the table. For one router I did, I just made new support arms that were 2 inches taller. But you still may be limited by the amount of the Z travel.