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An Introduction to Clamps and Clamping

A Finish Carpetner clamping up a window assembly on the job site. CLAMP · Pronunciation: \'klamp\

1: a device designed to bind or constrict or to press two or more parts together so as to hold them firmly. Any of various instruments or appliances having parts brought together for holding or compressing something.

2: to fasten with or as if with a clamp



Picture frames to window frames, small projects, big projects

A woodworker always needs a mechanical advantage during assembly. Whether it is to hold wood components together while the glue dries, secure a component in place while a mechanical fastener is used, or because you just don't have enough hands – the tool we have come to rely on is the clamp.

Woodworkers, regardless of skill level need a fairly broad selection of clamps and it seems that no matter the inventory – it never seems to be adequate.

Clamps come in all shapes, sizes and colors, and each has their own purpose or use, from pipe clamps to band clamps, F-clamps, miter clamps, spring clamps, you name it! Most of them simple hold piece of wood together in a simple joint, but there are specialty clamps that hold banding material on, hold chair legs tight for repairs and make our perfect miter cuts be true to our vision.

Clamps haven't always been around.

Early Egyptian craftsman applied glue to the edges of boards, placed them in jigs and applied weights until the glue set. This was more a clamping technique than hardware. When more pressure was needed, the boards would be wedged between an object and a wall. This wedging action was accomplished with bent sticks, or from opposed inclined planes. This may be where the term "between a rock and a hard place" originated.

Another technique was to bind boards with cord. Inserting a stick into the cord and twisting, similar to a tourniquet, could attain significant holding power. This technique is still used to this day by furniture restorers.

With the invention of the screw by Archimedes, things improved a bit. Screw-based gadgets were commonly used to squeeze juice from fruit and the oil from olives in a more efficient manner. This type of mechanism was modified into presses for making paper and applying ink to print books. Simplifying the application, a new technology was advanced – these presses became holding devices. Early devices were named for their application like window or door clamps. Modern clamps took on names based on their generic shapes such as "C" or "F" clamps. Today's engineering has brought us full circle since we seem to be back to naming clamps for their application again: miter, wedge, 90°, etc.

Variations in design: movable blocks, multiple screws, and opposing screws gave birth to vises and clamps. Modifications continue today, with new types of clamps being introduced into the workshop routinely.

What follows is a summary of the most common woodworking clamps in use today.

This list will, no doubt, be outdated shortly after this newsletter is published and it should be noted that this is, by no means, an all inclusive list. There are hundreds of specialty clamps on the market, including a whole slew of clamps designed to make pocket hole jigs easier to use. In the hands of a creative woodworker, the uses of these tools, which we often take for, granted, will continue to grow – and, we haven't even discussed vises!

Classic Wooden Handscrews
These are the classic cabinetmakers bench clamps used for gluing and assembly. Their carbon steel screws pivot to allow the jaws to grip nonparallel surfaces or let you offset and/or angle the jaws however you need to keep parts from shifting. They have a deep throat and can be used to apply a broad area of evenly distributed pressure or concentrated at one point of contact.

Spring Clamps

Probably the most widely used clamp. With rubber tips to prevent scratches, these clamps allow instant opening and closing where fast, easy application or removal from work is required and where spring pressure is adequate.

F-Style Bar Clamps
Cast metal heads, coated steel bars, wooden handles and swivel pads. Inexpensive and provide good clamping pressure. Work well in 12" to 24" configurations. Longer versions tend to bow and are not very well suited to even pressure. Metal swivel caps require the use if shim or felt pad to prevent marring the work piece, but have a tendency under pressure to slip of the work piece.

Parallel Clamps
The large, flat parallel clamping surface and jaws that stay perfectly parallel make these clamps ideal for accurate clamping of casework and drawers.

Quick-Action Bar Clamps
Every Shop has them -- perfect for all work that needs to be carried out with one hand – overhead tasks, or if the other hand is needed for aligning purposes.

Pipe Clamps
A staple of cabinet makers for years because clamps of any length can be created. Pipe clamps are comprised of two fixtures: a head assembly and a tail stop assembly. They are used on standard 3/4" or 1/2" black pipe. The tail-stop features a multiple-disc clutch for fast easy adjustments while holding work securely.

Big Jaw Pipe Clamp Fixtures
A variation of the popular pipe clamp, big jaw clamps are made of heavy-duty ductile cast iron, feature a big 7" reach and have multiple-disc clutch plates for ease of adjustment and quick release. Used when more then just pressure along an edge is needed, such as veneering or gluing up large turning blocks.

Machinist's "C" Clamp
Not really a woodworking clamp, but you'd be hard pressed to find a shop without it. Good general duty clamp for light applications. Pads or shims are required to prevent surface marring.

Rapid Action Band Clamp
Popular with furniture repair and restorers, this simple ratcheting clamping band easily secures work pieces in seconds. The 1" wide nylon web band exerts a steady 1500 lbs. of pressure on your work piece.

Corner Band Clamp
Picture frames, hexagon, circular and just about any other shape, can be securely held with this clamp. The 6' nylon strap is neatly contained in its own reel, and 4 variable angle pads allow virtually any shape to be clamped. Just fit the strap around your work, flip the strap locks and turn the clamp handle to apply pressure equally around your project. Extra corners are available for projects with more than four sides.

3D Squares
These are more jig than clamp. Machined square and made of metal or plastic they are designed to easily clamp on to a project making it simple to square up corners.

Pinch Dogs
Pull joints together when driven into end grain along a joint, these simple steel "clamps" draw boards tightly together for gluing up panels, table or bench tops, and can be used again and again.

Cam Clamps
These versatile, wood clamps are widely used by furniture restorers, cabinetmakers, luthiers and hobbyists. They are light weight and have a quick cam action that produces 330 lbs. of pressure when fully cocked. The bar is made of spring steel, the body is maple with cork faces to prevent marring and staining.

Kreg 90 Degree Corner Clamp
Combination jig and grip clamp, this innovative design lets you quickly square and secure individual joints on drawers, shelving, etc.

The BESSEY VarioClippix Clamps
A clever variation on a spring clamp, the unique design of this variable capacity clamp lets you create an infinite range of openings up to 6", with constant, firm pressure at all openings.

U-shaped rail clamp
This light-duty bar clamp has a U-shaped rail that enables step-over clamping for those hard to reach spaces. Throat depth is 2", with a clamping force of 330 pounds.

Clamping Square & Wedge
These machined aluminum clamping squares and the clamping wedge mate up perfectly to create a fixture for forming miter joints. You can maintain positioning and alignment by attaching the wedge to a toggle clamp with a threaded stud.

Spring Miter Clamp Set
This is one of the quickest and easiest way to clamp mitered corners. Great for moldings and trim too. Simply choose the appropriate size spring clamp and use the spreader to open and position the clamp.

Picture Frame Miter Clamp
This tool allows easy clamping of all styles of picture frames up to 48" x 48". Plated rods are fully threaded and thumb nuts make accurate adjustments of the corners quick and easy.

Self-Squaring Frame Clamp
Tightens all four corner joints equally and simultaneously with just the turn of a central wing nut. Jaws leave joints visible for inspection, easily adjust to accommodate frames from 5" x 7" to 26" x 30".

Corner Clamp
Perfect for picture framing. Whether you're simply gluing or using fasteners, this miter style clamp will hold stock firm and square at an exact 90 degrees.

Learn more about what clamping solutions are available to the modern woodworker – click here.

From pipe clamps and bar clamps to specialized work holding solutions, you'll find the perfect clamp for every woodworking project at Rockler.


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