Basic Principles Required in setups for Milling Precision Work

Basic Principles Required in setups for Milling Precision Work Points : Basic Principles Required in setups for Milling Precision Work 1. Precision milling begins with a clean table that must be free of chips, burrs, and dirt. This is the first. and very important step in setting up work. Keeping the work, the table, the vise, and all other tools clean is a “must” all through the milling procedure. Before mounting cutters on an arbor, be sure to clean each of the arbor collars, the arbor itself, and the cutter that is to be clamped between the collars. The smallest chip wedged between the collars can give trouble when doing precision work. Before placing a, vise, fixture, or attachment on the table, be sure to clean all contacting surfaces.

2. Work-piece held in a vise should always be seated on parallel bars when the thickness is less than the height of the vise jaws. Searing work properly on parallels requires tapping the work down, using a soft hammer or block and testing with the fingers to make sure the parallels are not lose at either end. If parallels are loose, the work is not seated properly.

3. When selecting a cutter or cutters for a job, bear in’ mind that a milling tool’ & cut is not complete until it clears the end of the work. The center of the cutter must travel a certain distance beyond the end of the work-piece before the cut is finished. To save milling time, select the smallest diameter cutters that will do the job.

4. Before mounting cutters on the arbor, decide in which direction the spindle should rotate. Then mount the cutter to cut in that direction. After the cutter is mounted, check to see that the spindle is set to turn in the right direction. if fed against the work-piece, a cutter revolving in the wrong direction could ruin the cutting edges of the teeth. When mounting cutters on an arbor, be sure they fit freely. Cutters must never be forced on an arbor. An arbor that has been scored or burred should not be used until the burrs have been removed. Good milling practice requires that both the work and the cutter should be located as close to the machine column as possible. A good rule for setting up milling work is to set up the work first, then move the table as close to the column as is convenient, and mount the cutters to be used. This provides, a good, rigid setup.