Focus: GD&T and Manual Machining
A vise jaw stop is a tool used by machinists to achieve repeatable results. It clamps down to the edge of the vise on a mill. When a block of metal is placed into the mill, the machinist slides this metal part up against the vise jaw stop and then clamps down on the part with the vise. Because this vise jaw stop is rigidly fixed in place, the metal part can be taken out of the vise and replaced with precision.
Above is a standard vise jaw stop that I have used in the past. My design, inspired by other products available, uses an adjustable steel rod that sits below the level of the vise jaw as the stop against which your metal part rests. This allows for comfortable machining of small or flat parts by staying clear of a drill bit or an end mill above.
The design and drawings for this tool were made in SolidWorks (click on the images to enlarge) while the manufacturing was done entirely on a manual mill. I started by squaring up two small blocks of 304 stainless steel, a durable and machinable alloy. I then drilled the holes for the sliding pins and tapped holes for the bolt to pass through.
This was a crucial step. If any of the holes were out of square, the clamp mechanism would slip and the vise jaw stop would loosen. I cut away an edge to grip the vise jaw and chamfered the top faces. Then it was time to assemble the nine-part tool.
One thing you may notice, if you look carefully, is one of the bolts that acts as a set screw for the adjustable rod is broken. This was an unfortunate mistake that I made at the very last step of making this tool. As you can see in the 3rd picture above, the set screw tapped holes are blind and only about 3/16″ deep. My error lies in using a plug tap rather than a bottoming tap. The result of that decision was the threads at the bottom of the hole were not fully formed and caused the bolt to bind up. The head of the bolt sheared off when I tightened it. The moral of the story was to always use the right tool for a specific job, no matter how small.
