What's the Big Deal?
“Work” is the stock you have and part you are creating. Workholding, or how you physically attach your work to the mill, is the most critical part of the machining process.
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They clamp into the part with little spikes, which provide a strong grip, but leave marks in the parts.
Mitee bites do not hold parts concentric or parallel to the face of the jaws. They are most often used early in the machining process.
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V-blocks sit inside the vise and get clamped along with the work. They are ground and can hold parts very concentric. There are a few different sizes of v-blocks depending on part size. You always want to make sure the part is sitting on the flats of the v-blocks, and not so large that they only touch the outer edges. Only one v-block is needed, as long as the third point of contact is another well-defined surface.
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