Hi @BrockW,
Thanks for reporting on your testing. If the flare go away by just rerunning the file (be it 4 times…) this seems to confirm it’s a matter of deflection: each pass has fewer material to remove than the previous one, therefore lower cutting forces, therefore less deflection. MDF is so soft that the second pass does it, and maple is quite harder so I can how it would take more passes.
(Side note: the square body being exactly 1" before all passes are done could be a coincidence that the machine X/Y calibration is not dead on, have you tried cutting a very shallow pocket with a square endmill and checked dimensions ? But let’s ignore that for now)
That said, it should not be required to do multiple passes to get a clean vcarve in maple.
- unless I missed it, you did not mention your cutting parameters (feeds and speeds and depth per pass) ? A lower depth per pass would probably help deflection.
- there is a fantastic thread from @LiamN about machine deflection (among many other things), it may be a lot to take in but for starters you should check ALL your vwheels (they need to be nice and snug against the rail, but not too much, it’s a Goldilocks thing). I know you said you do not feel any play in the Z axis, but sometimes the play comes from the gantry (X/Y axes).
- Then, you can try raising the router (and therefore also raise the stock) such as to minimize the lever effect around the X axis. This will also reduce deflection.
On a mechanically sound machine and with conservative feeds and speeds and depth per pass, maple should vcarve accurately without the need for a second pass.