- Example 1: vibration, poor surface quality
- Example 2: different orientation, same result
- Example 3: expert advice
Figures 1 and 2. Show the alternative efforts to hold the workpiece vertically in a vice (Figure 1), and vertically in a vice and clamp with a bolt and nut (Figure 2), but both efforts resulted in the same poor quality finish.
Our frequent correspondent has delivered three useful examples of fixtures, designed in the machine shop and their effects for a specific workholding task:
“In the first example, the fixture was designed in the shop. (See Figure 1.) The blank was made from forging steel, and the task involved machining a slot.
The blank was held, gripped in a vice on horizontal support on the milling machine. Machining was done by a milling cutter with a horizontal head. The blank was held in vertical position in a vice.
As result, there was a terrible noise from the vibration of the end of the blank, and a poor quality surface from the machining because of the vibration.
Second Example — Seeing the negative result in the shop, the operator then tried to hold the blank in a vertical position (See Figure 2), using a gib clamp with bolt and nut.
The result was same that in example first.
Third Example — In the third example (See Figure 3), a tool-designer offered this design for a fixture. The blank was placed on a horizontal fixture on the horizontal support of milling machine, and a vertical head was used with same milling cutter. The blank was held on the fixture with bolts and nuts.
The result: No noise due to vibration and good surface quality on the machined part — and thanks from shop.”