The vise is an invaluable stationary hand-tool that is often used & abused and frequently overlooked for care. A vise, in any of its innumerable manifestations, simply anchors a work-piece, providing a stable platform to use most other P&O hand-tools.
Machinist’s vises are most commonly used in P&O due to the large volume of metal products we work with. The diagram below shows the parts of the vise and what they're called.
The base of the vise is secured to the workbench with bolts. Loose bolts and a poorly constructed workbench can reduce the effectiveness of a vise. If the vise is a “fixed” vise then the base can also be referred to as the body, if it has a swiveling base, the base and body are separate parts.
The Fixed Jaw
The fixed jaw is the stationary jaw on a vise. There is typically a flat anvil-like horizontal face on the body of the vise behind the fixed jaw. Only vises with this feature should be used as a base for striking. Like anvils, this surface has a steel face on it that is more resilient than the brittle cast iron body, allowing it to be repeatedly struck without the risk of fracturing.
The movable-jaw is adjustable in order to secure the work-piece. Some vises come with a quick-release feature in the form of a lever to one side of this jaw. When depressed it disengages the screw mechanism, allowing the movable-jaw to be slid in or out without turning the handle. This feature is great for quickly adjusting the vise.
Screwed to each of the Jaws are the jaw faces. These are almost always made from hardened steel and have a knurled surface (a diamond-shaped cross-hatching) on them to grip the work-piece. They are removable for replacement when damaged. The vise is designed to function with these in place, without them the jaws won't meet correctly, or may not come together at all.
The handle provides the leverage needed to secure the jaws against the work-piece. The handle is free to slide and turn within the hole of the screw mechanism, providing the ability to move it to the side where leverage is needed and to be dropped or slid out of the way as required.
A vise needs to be installed correctly for it to serve its purpose correctly and not lend itself to injuring the user.
Every vise needs to be secured to a solid object, like a workbench. The workbench should be a sturdy one able to take lateral forces without racking or torquing and support the weight of the vise and the weight of whatever may be put between its jaws. If the workbench isn't fastened to the floor, there needs to be a mass placed on it that can absorb the lateral forces that will be at play. With every movement of the vise and bench, the user wastes energy and time. Those forces that were intended to work the piece in the vise get spent on moving the vise around instead.
Each hole in the base of a vise must have a correctly sized and secured bolt in it, through a correctly sized hole in the bench with washers and lock-washers (or nylocks®). As silly as it may seem to mention, make sure the bolts go in from the top and not from underneath. If the nuts do work free of the bolts over time, at least the bolts will stay in the holes and not drop out and let the vise shift or even fall off the bench. If a vise is moving when in use, check that the bolts are tight. A loose bolt will also damage the bench by elongating the bolt hole(s) and cause the vise to wear away at the bench-top.
When installing a vise it needs to have the fixed-jaw jaw-face proud of (sticking out from) the front of the bench to allow workpieces that are longer than the vise is tall to be secured vertically. Be careful when swiveling a vise with a workpiece secured this way, the piece could be damaged or you could be injured in the process.
Ensure that the height of the upper surface of the vise (jaw face) is at or just below (+/- 1cm) the bottom of your elbow when flexed, to avoid injury due to bad ergonomics and to expend your energy efficiently and effectively. This will position the workpiece to best take advantage of human bio-mechanics and afford better control of the tool in use. If the bench is too low, and it belongs to you, a solid wood block can be installed under the vise to raise it. If the vise is too high and you can't shorten the legs, a mat or small secured platform may provide the height needed.
Closing a vise is very simple, just remember “Righty-tighty”. Rotating the handle clock-wise brings the jaws together.
Without a quick-release feature, the fastest way to close a vise is to place a finger or two against the right side of the dangling handle and pin-wheel your arm about the elbow until the jaws engage the workpiece.
Make sure you leave enough room between you and the vise and always be aware of what’s going on around you, or you may not be the only one getting hit by the unforgiving steel handle.
To secure the workpiece tightly, a firm cinch is needed. When doing so, it’s always a good idea to move the handle from the distal (bottom) end while it’s in the hanging position. Rotate the handle until the jaws grip the piece you are securing, slide the handle to the right, if it isn't there already, and lean on the handle using your body mass, more than your arm muscles, to cinch the piece in place. Then be sure the handle is out of the way before starting to work the piece.
Opening a vise is equally simple, just remember “Lefty-loosey”. Rotating the handle counter-clockwise undoes the vise and opens the jaws. To quickly open the jaws without the quick-release lever, follow the
directions for closing, in reverse, after releasing the workpiece with a firm downward thrust on the handle on the left side of the vise. Be sure to keep hold of the workpiece!
Some vises have pivoting bases. To change the alignment of the vise, loosen the pivot handles (1), rotate the vise to the desired angle (2), and re-tighten the handles (3). As noted in the Clearance section, be careful swiveling with a workpiece secured in the vise, the piece could be damaged or you could be injured in the process.
When not in use the jaws should be kept almost closed. This keeps the vise in its smallest profile, and out of the way of passersby. This also ensures that the mechanism doesn't bind, making it quicker and easier to open when needed.
Working a piece in the vise is a balancing act. We don't want the piece to move but at the same time we don't want to damage it.
As P&O professionals work has to look professional and impart a sense of quality to the end user, to that end the surfaces need to remain unblemished.
To avoid damaging the workpiece there are two options: Sacrifice or Protect.
When we talk about sacrifice, we mean the portion of material that we put into the vise is the part that we will be discarding. Mandrels or other things that are not part of the definitive device can be secured without undue concern. When mounting a workpiece in a vise for cutting, if at all possible install it horizontally and level, with the cut as close to the vise jaw as possible. This keeps the moment arm short, the piece stable, leading to straighter and truer cuts.
If the workpiece is protected from damaged in the first place, it won't need to be repaired later. There are a number of ways to insulate a workpiece from the damaging effects of the vise jaws.
There are commercially available jaw covers made of a number of materials specifically for holding other materials. Various specialty vendors carry them.
But in school, a ready option can be found in the scrap bins; Cotton webbing can work, and even better are scraps of leather. Generally, the thicker and stronger the protective material the better.
The workpiece can be wrapped in leather … Or, the jaws themselves could be covered…
If you find some good pieces, keep them, because you may not find any when you need them the most.
Hand held power tools are designed to be held in the human hand and have been designed with the appropriate safety features for handheld use. When a powered hand tool is placed in a vise, it essentially becomes a stationary tool and no longer has the appropriate safety features to protect the user. So...
A vise is NOT a viable mount for ANY power tool, EVER.