Carving Too Deep

I am having an issue with my XCarve cutting too deep into all my projects. I put tabs on the projects and the xcarve blows right thropugh them and into the wasteboard, doing any extra pass into the wasteboard and usually destroying the project. I have tried cleaning out the collet and collet adapter, made sure the bit is not slipping, tightended the rain bands and still no luck. I use electronic calipers to ensure i have the correct depth of the material and always double check it. I used a speed square to ensure that everything is aligned and it seems to be straight on squared up.

Is there a way to run a quick Z-Axis calibration test? I am new to CNC routing and any help would be appreciated.

Give this a try. How are you setting your Z-zero position?