Above: G- clamps come in a wide range of sizes. Also shown are three self-grip clamps (right), two red and black sliding screw clamps and a small edging clamp (top)

It's next to impossible to saw or drill through a piece of wood that is skating around on your work surface, and if you don't hold a frame together while the adhesive dries the joints will be weak. For all these jobs, holding the work securely is almost as important to success as your skill in working on it.

Although there are dozens of different types of holding and cramping tools, all of them are designed for cramping two things together, either a work piece to your bench, or two work pieces to each other. The commonest type is the G cramp, which is available in a wide range of sizes or jaw capacities com­monly from 10mm to 200mm. You need a range of sizes for general woodworking use; the larger cramps can obviously cope with bigger work pieces, but are too heavy for use on delicate work.

Another useful type is the sliding screw cramp, a variation on the G cramp, that is often quicker and easier to position.

There are also several patented proprietary variations on the basic cramp theme, combining instant setting and release with an ingenious pincer action and interchangeable jaw facings. Special cramps are available for jobs like holding edging strips to shelves and table tops (edge clamps) and for making mitred assemblies such as picture frames. The latter sometimes incorporate saw guides, allowing you to cut and assemble the joint using the cramp as a jig.

String, corner and mitre clamps for mitred frameworks

Sash clamps have one fixed and one sliding head on a metal bar. Clamp heads fit on a timber bar

Bench aids include the bench hook (top centre), the holdfast (left centre) and various vices

Portable workbenches can clamp large objects with ease

For cramping large frame and panel assemblies during construction, you need sash cramps. As their name implies, these were originally used for cramping up window sashes and the like. They consist of a long bar with a series of holes in it and a fixed head at one end. A second head slides along the bar and can be locked to any one of the holes. The cramp can then be adjusted for span by screwing the fixed head in or out, as with a G cramp. An alternative approach is to buy just the sash heads, and to use these with a wooden bar. You can, of course, use many of these cramps to hold work pieces securely on your workbench as well as to cramp two work pieces together.

However, there are several other cramping tools designed solely to hold work pieces steady. The simplest is the bench hook, which allows you to steady the work piece with firm hand pressure while sawing it. A holdfast is a bar with a clamp head at one end, designed to be dropped into a hole in your bench surface and tightened down onto the work. Then there is a wide range of bench vices, some designed for woodwork and others for metalwork; all can be attached to the bench temporarily or permanently.

For assembling things like chair frames, a webbing clamp is invaluable. This is a tough belt which is passed round the frame to be clamped, and is held tight by passing the ends of the belt through a screw up tensioner. A smaller scale version of this, consisting of four plastic corner blocks and a length of nylon string, is a useful alternative to the mitre clamp when assembling small picture frames.

Finally, one of the most useful cramp­ing devices available is in fact the port­able workbench, of which the Workmate is the best-known example. This not only functions as a work bench (with variable height on some models); it can also be used as a giant clamp for holding things vertically between the fixed and movable halves of the bench surface (allowing you to plane the edge of a door, for example) and horizontally (with the aid of bench dogs, for cramp­ing large frames).