This calculator produces a table of carriage and cross slide movements. With this table an operator can use a lathe equipped with the parting tool of choice to mimic a radius tool cutting a round groove in the side of a part. The calculator will produce this table using the chosen step size for either roughing out a groove or for producing a groove that requires minimal filing.
The program needs three parameters to produce the table of cuts: the radius of the desired groove (e.g., 0.250), the width of the parting tool and the step size (e.g., 0.010). Both should be entered in decimal form. (Entering fractions will produce an error of some type, dependent on your browser.) The program assumes that the stock to be cut is more than twice the groove radius in diameter. (Or you will be mimicking a cutoff tool!) The default precision is three decimals, but this can be changed as desired. The final parameter to enter is the filing "buffer". Using the formulas precisely will take the corner of the cutter right up to the circle. Any movement past this point will result in cutting too deep. Since filing is required to remove the shoulders, a little extra can be built in to avoid cutting too deep.
If "Filing Buffer" is left empty, a default of 0.003" will be used. (The picture shows a large and inconsistent buffer.)
To use the chart the following procedure is recommended. A parting tool is centered on the groove width and used to cut a slot to the depth of cut listed in the table. The carriage is then moved one step to the right and the cross slide is advanced according to the value in the table. This is repeated using the same chart, but now the tool starts back in the original cut and advances to the left. File as needed to produce the groove of your dreams!
The x's and y's listed in the table may be of value for a lathe equipped with DROs on both axes.
Reload the browser window/tab between calculations if you don't want successive calculations appended.