You can use a door hinge type attachment on the back of the tool, which lifts the entire tool clear after each forward stroke
Saw it a while back being used to make a t slot
Basically the lower hinge drags up the top of the workpiece during the forward stroke
When the tool clears the cut it runs forwards another inch or two
this allows the 90 degree hinge to drop down straight to 180 degrees, falling behind the tool
this then lifts everything clear of the workpiece on the return stroke
It's an old shaper/planer users trick and seems to work well and is mainly dependent upon enough clearance at the end of each stroke
Edited By Ady1 on 19/03/2013 11:48:51