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Figure 3-Center drilling a part clamped to the table with the P/N 3012 hold-down set. The newer P/N 3013 step block hold-down set is more quickly adjustable for height and covers a wider clamping range.

  • Avoid exotic materials, such as stainless steel, unless absolutely necessary because of machining difficulty and poor milling cutter life. (Probably, if each new mechanical engineer were given a block of stainless steel to mill, drill and tap upon his graduation, stainless steel sales would drop considerably!)

  • Before beginning, carefully study the part to be machined. Select the best surface from which to work (usually the flattest).

  • Pick a point from which to measure that will not be machined off part way through the job.

  • Decide if work should be "rough cut" to size. Some materials will warp while being machined. Close tolerance parts can be destroyed by attempting heavy machining at the end of the job rather than at the beginning.

  • The method of holding the work is also determined by the type of machining to be performed. For instance, work that involves only small drilling jobs does not have to be held as securely as work to be milled.

  • Lay the job out so that it can be machined with the minimum number of setups.

  • Be sure to have all needed cutting tools available before beginning a job.

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