Review on 🔩 LAPOND Screw Jig: 2-in-1 Dowel Drill Guide Kit for Precise Woodworking Drilling and Punching - Adjustable Doweling Jig with 4-Hole 6/8/10/12mm Pin - Ideal for Bed Cabinet Screws and Punch Locating by Doug Virden

Very strange design. First, rubber washers are placed on the knurled screws where the guides have to be pressed in. But that makes it impossible to pinch it. Then when you remove the rubber washers the thumbscrew goes in where the rail screws are so you can't screw the rail in (see picture). You can fix this by putting a real washer between the thumbscrew and the case, but why didn't they do that from the start? And even if you tighten it fully, there is still some play in the corner of the guides. Generally, for $40, you're better off just building your own device. Search on Youtube. I'll come back and do my thing.