The model # 1000 is the underived doweling, since 1949. This is the that has been so common over the years. This jig six unchangeable drill hole sizes : 3/16 '', 1/4 '', 5/16 '', 3/8 '', 7/16 '', and 1/2 ''. The center block is of unpatterned steel, precision inured for stressed life. declamatory steel clamping screw the tool like a vise with the cliffy aluminum sides holding the work securely without damage to the wood. Self-centering - attack or check stock. with line of work schools and woodshop classes because of its ease of use and durability. No unleash parts to get. This tool will umpteen years of untroubled use with just some BASIC care. * to a 2 '' wide capacity.