After using CAD and Cut3D programs to create a 3D part for a toy steam locomotive. The 3D part needed to be cut out of 1-1/2" thick wood board. After running the code in Mach3 program for about an hour, I found out that a nut on the Z-Axis carriage on my home-built CNC router will hit a hold-down clamp so I had to hit the E-Stop switch with about 1/4" remaining to be cut. I was using 1/4" diameter straight router bit for rough cutting. I think that the 1/4" diameter core box router bit will be too short and I may not be able to do finish cutting because either the Z-Axis carriage or the collet nut will hit the board. Any suggestions?

yea, Cut3D, has a feature in where you can do a "Front and back".