PROPER USE AND CARE OF HAND TOOLS
 

CLAMPS
C-Clamps | Machinist | Deep Throat C-Clamps | Welder's C-Clamps | Bar | Pipe | Well Driller | Web | Handscrews | Spring | Miter | Specialty | Do's and Dont's


INTRODUCTION
Clamps are versatile tools that serve as temporary devices for holding work securely in place. They are used for many applications including carpentry, woodworking, furniture making, welding, construction and metal working. There are many clamp styles including C-clamps, bar clamps, pipe clamps, handscrews, etc. In selecting the proper clamp style and size, match the work-holding requirements of the application with the following clamp features:

  • strength and weight
  • opening-length of reach
  • throat depth – depth of reach
  • ease of adjustment
  • clamping surface – material used and size



 

C-CLAMPS

The most common clamp is the C-clamp. C-clamps vary in size and strength from a 3 oz. aluminum clamp with a 3/4" opening to a 40 lb. heavy-duty drop forged steel C-clamp with a 12" opening. C-clamps generally have four parts: the frame, the screw, the handle and the swivel pad. The frame is usually made from stampings, castings and drop forged steel. Generally drop forged steel provides the most strength. Most clamps have a sliding crosspin handle or a wing nut for tightening the clamp. Certain heavy-duty clamps have screws that end in a square head and the tightening is done with a wrench. The swivel pad at the end of the screw allows the clamp to position itself on non-parallel work and prevents work from being marred. Certain C-clamps designed for heavy-duty applications are designed without swivel pads.

The C-clamps, like any fine tool, can be damaged by rough handling, improper job selection, and over-loading. Keep C-clamps in racks when not in use to protect them from damage. Use clamps of the proper capacity. You wouldn't drive a railroad spike with a tack hammer – and neither should you use a light-duty clamp for a heavy-duty application or a large, heavy-duty clamp where a small light-duty clamp would do the job.

FIG. 46. This type of extra heavy-duty forged steel clamp uses a wrench for tightening.


FIG. 47. Typical C-clamps.


 

MACHINIST'S CLAMPS

Machinist's Clamps somewhat resemble C-clamps but are made entirely of drop-forged steel. Their jaws are parallel to each other; they cannot be set to non-parallel positions. Two screws, one in the center and one at the end are used to tighten the clamp against the work.

Always choose a clamp in relation to the work involved. Too large a clamp may prove to be an awkward obstruction causing hazardous working conditions, while too small a clamp will not provide adequate pressure to hold the work securely.

FIG. 48. The Machinist's Clamp, designed for pattern-making and machine shop use, is made of tough steel and heat-treated for extra strength.

 

 

DEEP THROAT C-CLAMPS

As a general rule, the larger the clamp, the deeper the throat. However, there is no need to go to extra large C-clamps just for the sake of the extra wide throat capacity that may be needed. The job can quite often be accomplished by using special C-clamps that have an extra deep throat, even though their overall size may be quite small in relation to its throat.

FIG. 49. How a number of C-clamps can be used to apply pressure to the center of a panel. The 1x2-in. boards transmit the pressure applied to them by the C-clamps to the 1x3-in. board in the middle. This technique is useful when gluing up large panels for veneering a door.

 

 


WELDER'S C-CLAMPS

Welder's C-Clamps are specially protected to prevent welding spatter from adhering to and eventually ruining the clamp. Its parts may be coated with a splatter-resist plating (copper or cadmium). In addition, welder's C-clamps are made with shields to protect the crew against damage.

FIG. 50. The Welder's Clamp.


FIG. 51. Another type of welder's clamp especially handy for holding odd-shape work.

 


BAR CLAMPS

A variation of the C-clamp is the bar clamp which consists of a steel bar with a fixed jaw at one end and a sliding or adjustable part that has a screw with a handle and swivel. In use, the sliding part that has the screw is pushed up to the work and then the handle is turned to tighten the clamp. Bar clamps vary in size from six inches to six feet in length.

Many bar clamps have disc clutches in the sliding jaw to engage the clamp at any place on the bar. These clutches provide rapid adjustment in addition to secure hold. Certain bar clamps use an "I" shaped bar which provides great strength for its weight. A crank handle is used for applying the final pressure.

FIG. 52. The bar clamp is extremely useful for gluing up extra wide work, as shown above.

 

 

PIPE CLAMPS

A close relative of the bar clamp is the pipe clamp or gluing clamp. It is used with ½-inch or 3/4-inch threaded pipe. The pipe is screwed into a fixed jaw and a movable adjustable jaw is installed on the other end of the pipe. In use, the adjustable jaw is pushed up to the work and the handle or crank of the clamp is turned to secure the work. The capacity of the pipe clamp is only limited to the length of the pipe available.


FIG. 53. These pipe clamps operate on the same principle. Their mechanism is mounted on half-inch or three-quarter-inch pipe. The clamp has its threaded part screwed to the end of the pipe while the back-up part can be slid along the pipe to the desired spot.

 

 

WELL DRILLER'S CLAMPS

This clamp is specially designed for holding and lifting pipe vertically. Pipe jaws are corrugated perpendicular to pipe. Do not exceed manufacturers' recommended limits for holding or lifting pipe.

 

 

WEB CLAMPS

These clamps have a heavy-duty nylon strap which is wrapped around the work to be glued or held together. By means of a ratchet, the web, or strap is drawn together to apply the required pressure. The web clamp is especially useful for gluing up large work (such as the outside edge of a table) as its capacity is limited only to the length of the strap.

Caution: Inspect the web for fraying or cuts before applying pressure as the ratchet action of the clamp develops tremendous pressure.

Keep these clamps rolled up when not in use. Be sure you remove all tangles and knots before applying to the work. The nylon belts are tightened with a small wrench while the heavy-duty canvas belts are tightened with their own built-in clamping handles.

FIG. 54. The Web or Strap Clamp is made of nylon. Its great advantage is that it can be used to apply pressure to large and oddly shaped work.

 

 

HANDSCREWS

The handscrew can be used to clamp work whose sides are not parallel to each other. This clamp has two screws, one with a left-hand thread and the other with a right-hand thread. The openings through which the screws pass are slightly elongated so that the jaws can assume a non-parallel position – if necessary – to match the surfaces of the work. The jaws move in opposite directions due to the action of the right-and-left hand threads as the handles are turned.

Keep the threaded rods of these clamps lightly oiled. But make certain that there is no oil on the jaws; and keep the jaws smooth to protect the work.

FIG. 55. The handscrew can be adjusted to clamp work whose sides are not parallel to each other. The smooth, hard wood jaws protect the finish of the work by spreading the pressure over a broad surface. One end of each spindle has a left-hand thread, the other end, a right-hand thread.

 

 

SPRING CLAMPS

While most people associate spring clamps with light-duty work, some spring clamps exert so much pressure that two hands are needed to open their jaws. These clamps range in capacity from one to four inches and available with vinyl padded jaws to protect the work. Use them only where moderate pressure is required for gluing or for holding work in place while some other operation is to take place.


FIG.56. The spring clamps are not to be sneezed at – they are for clamping! They range in capacity from one to four inches and are generally used for light-duty clamping. The holes at the handle ends are for hanging them up when not in use.


FIG. 58. The Corner Clamp has a dual function. It can be used to hold mitered corners together while the glue sets and it can also be used as a jig for cutting 45 degree miters.

 

 

MITER CLAMPS

The Miter Clamp is used to apply pressure to all four joints of a square or rectangular frame simultaneously. Two fairly common types are illustrated. However, ordinary C-clamps can also be used rather effectively to glue up corner joints as shown in the drawing on the next page.

Caution: Test for squareness at each corner before applying final pressure.


FIG. 57. This clamp is especially designed to apply pressure while gluing up mitered corners (such as picture frames). A thumb nut is at each corner. This clamp can also be dismantled for use when all four clamps are not needed as shown in the drawing to the right.


FIG. 59. How ordinary C-clamps can be used to apply pressure for gluing up a mitered corner.


FIG. 60. The three-way Clamp. An ingenious clamping device that allows pressure to be applied in two directions as shown. Extremely handy for applying veneers to table edges.


FIG. 61. Types of handles used to tighten C-clamps and bar clamps.


FIG. 62. This unusual C-clamp has a slot along its back and a spring-loaded threaded post which passes through the slot. The post can be positioned anywhere along the slot where it will do the most good and then tightened in place. Note the nut at the bottom which engages the post.


FIG. 63. This type of clamp features a serrated bar. To use, the movable part of the clamp is pushed up to the work and then the handle is turned for final tightening.

 

 

DO'S AND DON'TS WHEN USING CLAMPS

  1. Store C-clamps by clamping them in a rack, not in a drawer.
  2. Use pads with C-clamps to avoid marring the work.
  3. Discard any clamp that has a bent frame or a bent spindle.
  4. Do not use a wrench, pipe, hammer, or pliers, to gain extra tightening; a wrench should be used only on those clamps especially designed for tightening with a wrench.
  5. Keep all moving parts lightly oiled and clean; however, make sure there is no dirt or oil on any part that will come in contact with the work.
  6. Make sure swivel at end of the screw is turning freely before using.
  7. Never use a C-clamp for hoisting work. Special lifting clamps are made for this purpose.
  8. Avoid using extra large clamps just for the sake of their large throats; instead use deep-throat clamps.
  9. Never use a C-clamp for hoisting or for supporting a scaffold or platform that may be used to carry people.
  10. Do not use C-clamps for securing a load that may be carried over a public highway; vibration may cause the clamps to loosen and the load to break loose.
  11. Always remove clamps as soon as the required job is finished. Clamps serve only as temporary devices for holding work securely in place.


FIG. 64. Careful Cal knows enough to use the right size clamp and he places scrap wood under the clamps to avoid marring the surface of the work.

RIGHT


FIG. 65. Too big a clamp, and too much pressure will leave a dimple in the work. Hazardous Harry never seems to have heard that pads should be used with C-clamps to avoid dimples.

WRONG

 

 

Next Section


For questions regarding Klein Tools, please use the Contact Klein Tools page. For questions regarding Klein Tools' policy
regarding the use of this site, please see our Legal Notice/Privacy Statement.