Fractal bench dog/clamp for workmate

thingiverse

Updated version included pick the files with V2 Prefix for the improved copy. STEP file also included for those who want to make adjustments. After watching a restoration video by Hand Tool Rescue of a fractal vise (https://youtu.be/QBeOgGt_oWU), I was fascinated by the mechanism, it lets you clamp curved or irregular objects. I didn't find anything similar when I searched thigiverse, so I decided to design my own. Rather than designing an entire vise I instead designed a jaw that can be used as a bench dog, in workmate benches, or proper workbenches. The peg on this version is 0.77", 19.6mm, but I've included a 0.75" 19mm version as well. All parts were split so that printing could be accomplished without supports. The design is intended to be assembled with screws, but adhesive could work for most parts, except the retaining screws. A 0.3mm clearance was the basis of design, but the pin sides of the sliding dovetailed parts can be shimmed for printers that can't achieve this precision. either #4-40 or 3mm screws will work. V2 will accommodate a range of bolt lengths 10mm-16mm (3/8"-5/8") will fit. In V2 grub screws have been replaced with small cut lengths of filament inserted during assembly of the upper and lower halves. The following applies only to the original version (without the V2 prefix): 3 different screw lengths were used, 9/16"(14mm), 3/4"(19mm) and 1-1/8" (35mm) - Comments indicated that the long bolts are difficult to find, I tested an alternative. The long bolts are for retaining the middle stage, and do not fasten anything. taking another bolt of arbitrary length - I used a 12mmm, cut a piece of 1.75mm filament to make up a total length of 35mm, put the filament into the hole and then drive the screw in to retain it. This works just as well as the long bolts. If anyone wants a version with a different diameter, let me know and I can adjust that, or you can make your own to fit, the hole in the main jaw has a 3° taper to guarantee a tight fit. I designed the peg split so that it prints in the orientation for optimal strength. For doing real work, this should be printed with several perimeters (I used 4 and it seems quite tough)