1. Hspice Transistor Example

Hspice Transistor Example

Photo: FlickrA woodworking vise, according to its dictionary definition, consists of two jaws for holding work and a mechanism, usually a screw device, that opens and closes those jaws. That’s a rather broad definition, but then vises are a rather diverse lot.For convenience, vises are loosely categorized by the position on the bench they usually assume. Vises of a design suited for the right-hand end or “tail” of the bench are of a rather different shape from those typically found attached to the front or “face” of the bench.

Yet, as is true with most tools with long histories, not all vises fit neatly into simple subdivisions.You see, some of the vises attached to the front of workbenches aren’t truly face vises, like the leg vise and shoulder vise. And the engineer’s vise traditionally is set neither on the face nor on the tail of the bench, but actually on the benchtop.The bottom line?

Most woodworkers will find a face vise invaluable; almost as many would quickly learn to love the advantages of a tail vise if they don’t already. The sturdy engineer’s vise is essential for anyone who works with metal – which includes almost every woodworker, by the way, when it comes to sharpening, and dealing with all sorts of hardware and other components.Each vise has some specialized advantages, but you’ll have to make the call. And speaking of making, you’re luckier than your ancestors only a century or so ago. There are many kinds of vises in a myriad sizes on the market today.

If you wish, you can make your own but, unlike your great-great ancestors, you don’t have to.The Face Vise. Face vises are designed specifically for holding wooden workpieces while such operations as drilling and sawing are performed.The traditional material is wood. A wood face vise consists of a movable front jaw that is mounted to a broad, square beam that slides in and out of a matching channel. While the beam keeps the jaw steady and properly aligned, the jaw is driven by a wooden bench screw. The whole mechanism is fastened to the benchtop from below.

Modern variations of the wooden face vise are often called woodworker’s vises. Also mounted flush to the bench front, these are all metal (except for jaw liners of wood that prevent the damage that would result if the metal jaws were tightened directly onto wooden workpieces.Woodworker’s vises are designed to be attached to the underside of the front of a woodworking bench. The vise’s constituent parts include a pair of iron jaws, while its other components – its slides, drive, screw, and handle – are usually steel. Like wooden face vises, the inner jaw is fixed, while the outer jaw is operated by turning the handle centered on the front of the tool. Clockwise motion will tighten the screw mechanism, drawing the jaws together; a counterclockwise motion will open the jaws.

The Engineer’s Vise. This heavy-duty device is mounted on the benchtop, bolted to its surface. It weighs as much as an anvil. In fact, may even function as a hammering block now and again as many models have a flat surface behind the jaws designed for use as an anvil.

The engineer’s vise is also called a machinist’s vise, or sometimes a mechanic’s or railroad vise.The primary purpose of a machinist’s vise is to grab hold of things and to hold them steady in its rough jaws, freeing up both your hands so that you can bend, shape, hammer, cut, drill, or perform any number of other operations. The jaws of the vise usually have a machined face that can easily scar wood. Some models these days are sold with reversible jaws that are smooth on one side and serrated on the other. If you have frequent need of a metal vise and only occasional need for a wood vise, you may buy jaw liners.

Many machinist’s vises also have pipe jaws located beneath the main, flattened jaws.The base on many machinist’s vises swivels, accommodating a variety of workpieces presented at different angles.