Hitachi GR2000 - Manual (Page 335)

called UNDER SUPPORT instead of screwjacks. The steps are shown below.
1. Remove the M12 bolts attached or mounted to UNDER SUPPORT, and fasten
them temporarily to the M12 bolt holes for the screwjacks.
2. Insert UNDER SUPPORT between the bottom of the router and the M12 bolts
3. Tighten the M12 bolts.