Sine Keys and Vise Keys

Sine keys and vise keys position and align fixtures and vises on machine tables. They help position the part to be machined. Sine keys are non expandable O-ring style. Use the vise key step keys when the keyway in the vise is different that that of the machine T-slot. Standard keyways are used when they are the same width.

sine keys and vise keys
sine keys and vise keys
To start, reaming a precision hole is more efficient than cutting a keyway. It is easier to hold our precision location with a single bore then two entire surfaces of a keyway. This bore is also used as a basis for our other features (such as stationary jaw parallelism) and therefore a more consistent location transforms into a more precise product. It also allows us to put in additional precision holes to fit many grid plates (2”x2”, 40mm x 40mm, 50mm x 50mm) without adding additional cost to the final product. 
Next, our reamers are rated at a H7 tolerance, which is DIA +.0003 to +.0006. The reamer creates a more consistent hole size. This precision allows the end user to have less setup time as the tolerance stack up of the reamed hole and sine key are minimized.
Also, the slip fit between the reamed hole and the sine key do not cause any install/uninstall issues. An oversized o-ring is applied to the sine key, which gets compressed as it is installed into the vise, keeping it securely fixed in the vise body. The previous design utilized a small socket head cap screw, which required an Allen wrench for installing/uninstalling, as well as an additional time to line up the key in the keyway, hold it there, and install the SHCS.