【High-quality material】Concealed hinge jig device we use high-quality aluminum alloy material, precise manufacturing, accurate positioning, sharp bit, easy to use, wear-resistant and durable, long service life. This very practical woodworking punch is an excellent tool set for furniture factories and woodworkers to install concealed hinges on doors or cabinets. 【Double clamp design】 We have improved the three-bearing drill sleeve of Hinge Jig to reduce the swing distance of the drill bit and improve the accuracy of hole opening. Double clamps on the front and back, firmly fixing the layout again without damaging the finish. Applicable to door thickness: 15-25mm, opening depth 10-15mm 【Margin Adjustment Function】 The total height of the upper, middle and lower load-bearing drilling sleeve of Hinge Jig is 2cm. The higher the height, the lower the vibration of the drill bit and the more accurate the drilling will be. We have added the margin adjustment block and 2 adjustment screws, the