Use to make your own drilling jig, great for accurate drill positioning especially dowelling. This two part threaded drill guide can be fixed into a piece of MDF by boring a 20mm hole in the jig and screwing the guide bush in place. Drill a 12mm dowel hole, unscrew and reposition on the opposite side to drill the mirror hole for accurate dowelling. The jig is used as a positioning guide, more than one guide bush can be used. Suitable for duplicate holes, the simple design of this guide makes it ideal for many tasks including aligning dowels when jointing worktops. Sold individually. Suitable for the Lamello Invis invisible clamping system.