Screw clamp
The most unpleasant thing when using a clamp is if the washer (heel) sticks on the hinge and starts to scroll the part. The clamp then has to be removed, reinstalled, and a small detail may break.
To avoid such a situation, the heels of factory-made clamps are set on a ball stop, on the left in the figure:
Designs of screw clamps
It is unrealistic to make it yourself: in addition to precision turning, you also need a metal that combines high strength and toughness. Therefore, the clamping units of self-made clamps are most often made cup-shaped for a screw with a washer (drawings on the right in the same place). Such a clamp requires regular maintenance: the heel is rinsed in kerosene 2-3 times until the dregs of abraded metal no longer stand out. Then, 2-3 drops of a spindle, watch oil, etc. are allowed on the joint of the heel with the screw. liquid lubricant.
About carving
Threaded pairs of factory clamps, as you know, with a special thread - rectangular or trapezoidal increased pitch. The hobbyist will likely need to use a piece of threaded bar and a regular metric rolled nut. To prevent the clamp from jamming, you need, firstly, to pass the nut with the second tap, respectively. standard size. If the thread is larger than M12, then successively with the second and third taps. The bar is similarly passed by a die 2-3 times, until the die (stick) from a finger strike on the driver of the crank starts to "run" freely along the thread. Secondly, the threaded pair must also be regularly wiped with a rag with kerosene and lubricated with any grease for machines and mechanisms.
In conclusion, we give a video overview of various designs of washer for homemade clamps:
Video: washers for clamps
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Cam clamp
This device is not only useful but also extremely simple. It must be remembered that cam clamps are fast-acting, but they cannot guarantee a large clamping force on parts. This is why they are used when relatively low cutting forces are required. They are not suitable for high pressure applications, as is possible with a large clamp. However, they are extremely easy to use.
A special template is used for cooking. It is needed to create curves. The template is made of metal, plastic or wood. It is used to tighten smooth curves. However, the cams are not a direct tracking of the French curve. The correct cam should have a profile that increases the distance between the axis of rotation and constant speed. In this he resembles a spiral drawn with a pencil.
How to do it yourself
Ready-made tools are sometimes not suitable for some work, so craftsmen make them with their own hands. First you need to prepare pieces of chipboard or plywood with a smooth surface.
You can make the device in the shape of a triangle or rectangle so that there is one right angle:
- on both sides of the corner, stepping back three or five centimeters from the top, it is necessary to attach the bars with self-tapping screws;
- I lay the prepared segments on a flat surface and press firmly using ordinary clamps;
- to free access to the joint, it is better to cut off the protruding top of the corner.
The next step is dedicated to making the clamp clamp. You need to prepare the following parts: three nuts, a long hairpin or bolt, a handle, a bracket:
- for the base, a triangular shape will become optimal;
- the hairpin protrudes beyond the edges of the base in a state of full compression, without a part;
- a bisector is drawn from the corner;
- a nut with a bolt is fixed with a bracket at a distance of ten, twenty millimeters from the intersection of the bisector with the hypotenuse;
- make a metal bracket, bending it in the shape of a nut;
- holes are drilled at the edges of the hypotenuse;
- the bolt is guided by the head at the top of the right angle;
- a handle is attached to the opposite side of the bolt.
Such a tool can be made from wood, iron, aluminum, plastic.
When working with sheets for furniture, you need to prepare:
- plywood with a thickness of 8 to 12 mm, chipboard is possible;
- drill;
- jigsaw and hacksaw;
- rectangular or square wooden block.
We cut out several triangles with right angles, the legs of which are equal in length, and should be 25-40 cm. Depending on the size of the device of simple clamps, holes are made in the corners of the triangle. The distance should be 10-15 cm from the legs to the holes. Make two holes on the hypotenuse and screw the sheets. The device is ready.
It is better to make more than one tool in order to assemble the entire structure. Making them is not difficult, financially it is more profitable than buying ready-made ones, since this is not a universal tool. It is not suitable for all furniture assembly jobs. A self-made device can be made for any job.
Hacksaw for metal before modification and clamps obtained from it after modification
Assembly diagram
Equipment for stacking and tilting welded products
The stands do not provide tilting and turning of products during operation, which complicates the welding of bulky and heavy assemblies, therefore, special equipment is included in the welding installations, namely: tilters, rotators, roller stands, manipulators and positioners.
Tilters are stationary devices in which the elements to be welded are not only fixed, but also rotated around a horizontal or inclined axis in order to set them in a position convenient for welding, and sometimes to move during welding. Rotators provide marching rotation of the product around a fixed axis or around a number of axes lying in the same plane. The positioners have a manual or mechanical drive. Depending on the type of the rotary device, there are roller, lantern, trunnion (center) and chain rotators.
Rotators are devices for rotating the workpiece to be welded with a working or with a cruising and working speed around an axis that does not change its position in space. There are rotators with a vertical, inclined or horizontal axis of rotation. Rotators with a vertical or inclined axis of rotation of the BB (vertical rotator) are sometimes called carousel by analogy with turning lathes.
Welding rotator with vertical axis of rotation:
1 - faceplate; 2 - a bed with a rotation mechanism.
Roller stands or, otherwise, roller rotators or roller beds are designed to rotate and set the product to a position convenient for welding and to rotate the product at a working speed. The rotation of the product is made by driven, usually rubberized rollers, coupled to the product. A significant advantage of roller stands is that the rotation speed of the product, regardless of its diameter, is equal to the circumferential rotation speed of the rollers. A conventional roller stand consists of a system of idle and driven roller supports mounted on a common foundation plate. Olik stands are used not only for welding, but also for assembly.
Manipulators are called universal, usually stationary devices designed to rotate a product around an axis during welding at various angles of inclination of the axis of rotation.
Universal welding positioner:
1 - main bed; 2 - rotary bed; 3 - faceplate; 4 - mechanism for turning the faceplate; 5 - faceplate tilt mechanism; 6 - support paws.
The manipulator consists of the following main units: a bed, a turntable, rotary and tilt drives of the faceplate and a control unit. In most manipulators, all movements are mechanized. In some designs, the table can be tilted and raised manually. Some of them may not have a table lift mechanism.
Positioners, unlike manipulators, are not designed for welding rotation of the product and are only used to set and rotate (turn) the product into a position convenient for welding. Positioners or positioning manipulators are used both for fixing the product and for setting it in a position convenient for welding. All positioners are similar in design. They have two or three mutually perpendicular axes around which the faceplate with the product can rotate or tilt.
Positioner adjustment diagrams
The positioner table rotates and tilts by means of a manual or electric drive, it has only a cruising speed. Positioners for products weighing more than 1.5 t are usually electrically driven.
Joiner's pliers
Wooden temporary backs are used in carpentry as widely as steel ones in metalwork and welding. Due to the peculiarities of the main structural material, carpentry clamps are made almost exclusively of C-shaped (clamps-tongs).
The most powerful of the joinery clamping devices is the crocodile clamp, pos. 1 in the figure:
Varieties of joinery clamps
Sponges made of oak, elm, beech, hornbeam, walnut. Threaded pairs - from M12. Clamping parts with a "crocodile" is troublesome, so instead of it they often use a hinged screw C-clamp, pos. 2. Its "jaws" can be re-glued from plywood, and only the pads ("lips") can be glued from durable wood. Instead of a shaped nut, it is possible to use a conventional hex nut, pressing it into the handle in a vice; in this case, the handle must be made of maple, beech or elm; oak can crack when pressed.
Crocodile clamps are used to securely hold sufficiently large and heavy parts. When gluing a strong pressure is not needed, but a lot of clamps are needed, at least 3-4 per 1 linear meter. m of the glue line. Therefore, joinery clamps for gluing are most often made of plywood. Each "jaw" is re-glued from 3 or another odd number of layers. In one of the "jaws" with a protrusion there will be a middle layer, and in the opposite one there will be two extreme ones; thus, and with the help of a steel pin, a hinge is formed. The clamp is spring-loaded (pos. 3 in the figure), and made of available elastic materials, pos. 4.
Cutting and adjusting the blanks of plywood crocodile clamps is a laborious task, but a modern craftsman has an excellent substitute - cutting large-diameter PVC pipes. A split ring made of a pipe, a pair of wooden sticks, the same amount of garden hose scraps, and a clamp for pressing when gluing is ready, pos. 5. Cheap and cheerful. More about wood clamps, see the rollers:
Video: do-it-yourself wood clamps
To the second, we advise you to go to YouTube and read the comments, there are tips on the matter.
G-clamps
These devices are used for the implementation of most of the work, therefore, you need to buy more of them. They are produced in various sizes, but the most popular are those with gripping widths of 100 and 150 mm. G-clamps should be purchased only of high quality, because the brackets of inexpensive options often sag and it is quite difficult to work with them.
Specialized G-clips with increased grip depth can be found in stores. They help to reach out to places inaccessible to simple clamps.To fix the overlays, there are special edge clamps that can press the part at the same time in two directions. When choosing a G-clamp, it is worth making sure that the screws are large, the surface is flat, and the knob is thick with a rounded end.