I don’t know what tools you are using. In Fusion 360, I can pick a stock point on the bottom of my stock as a reference. If you cannot do this in your CAM software, you can:
- Zero against the spoil board
- Raise the router your material thickness as defined in your CAM
- Run a G92 Z0
needing to set my material thickness to 1-2mm thicker than the material
If everything is well calibrated and you’ve surfaced your spoil board, and you use that surface as your reference, you should be able to avoid most of this extra depth of cutting, saving your spoil board somewhat. Or maybe just not worry about it. I have a Primo, not a Lowrider. My spoil board has an array of threaded inserts, so replacing the spoil board is time consuming job, so I like to give it as much life as I can. If all you have is a sheet of MDF, maybe don’t worry about cutting up the spoil board as much.
Are there better methods for holding down the full sheet material?
I have a Primo, not a Lowrider. I expect the hold-down strategies for full sheet goods to be different than smaller stock. I suggest you ask this as its own Forum topic/question to see what other Lowrider owners are doing.
Rather than double-sided tape, you could use the masking tape trick. You apply matching masking tape to the spoil board and the stock, put CA glue on one side and activator on the other and push the two together. I’ve seen this done with shelf liner rather than masking tape for covering larger areas cheaper. The problem with this idea is that, with a full sheet, matching the tape on both surfaces could be difficult. It would be easy along the edges, but you have to do some planning out in the middle, or make the tape on the stock larger to compensate for errors.
If you plan on doing a lot of full-sheet cutting (like this is a business), you might consider making your spoil board into a vacuum table. I’ve seen DIY solutions that pull the air directly through the MDF, and I’ve seen DIY vacuum tables using shop vacs.