diff --git a/labsw/mech/Makefile b/labsw/mech/Makefile
index d1084c0..1e78dae 100644
--- a/labsw/mech/Makefile
+++ b/labsw/mech/Makefile
@@ -3,6 +3,8 @@ SHELL=/bin/bash
 SPOOL=/home/moko/svn.openmoko.org/developers/werner/cncmap/spool/spool
 CNGT=/home/qi/cae-tools/cngt/cngt
 
+BOARD = X0=8.5mm Y0=3.5mm BOARD_Z=1.6mm ENGRAVE_Z=0.5mm
+
 .PHONY:		all mill pos cng plot clean
 
 all:		mill.rml
@@ -16,7 +18,7 @@ logo.gp:	front.fpd
 		  [ "$${PIPESTATUS[*]}" = "0 0" ] || { rm -f $@; exit 1; }
 
 mill.rml mill.gp: front.gp logo.gp
-		./doit BOARD_Z=1.6mm ENGRAVE_Z=0.5mm CLEARANCE=3mm || \
+		./doit $(BOARD) CLEARANCE=3mm || \
 		  { rm -rf $@; exit 1; }
 
 mill:		mill.rml