Assembling a homemade band saw from plywood
Wood is a popular construction material: bar is used to build houses and outbuildings, boards are used for flooring and wall finishing. Band saws are often used for sawing lumber in the home. Factory models of equipment are not available to everyone because of the rather high cost. But you can save money by making a band saw with your own hands. Depending on the size and set cutting blade it will also be possible to work with different metals and their alloys, stone, synthetic materials, such as polypropylene.
Domestic inventors have proposed various designs of machines with band saws. For self-assembly is suitable model of the sawmill with vertical positioning of the cutting blade, which consists of the following main assemblies and parts:
These structural elements of the machine and the smaller parts with reference dimensions are shown schematically in the drawing below.
Very often 220 V electric motors are used as the drive.In this case, the more massive is planned to saw the workpieces, the more powerful motor is recommended to be installed. Three-phase motors (designed for 380 V) are also used. But for stationary networks such variant is connected with some additional problems: it is necessary to adapt the electric motor to 220 V network, having established for this purpose phase-shifting and starting capacitors. Gasoline (diesel) internal combustion engines can also be used instead of electric motors.
The solid cutting blade is fixed on pulleys. Workpieces are sawn through its movement in a closed oval or circular path.
A small table-top machine can be made. The jigsaw model is shown in the photo below. Guided by it, to assemble the device will not cause any problems, even without a detailed description of the whole process.
Important! In general, the size of the created equipment depends on the upcoming tasks, which are planned to solve with its help. For splitting logs on a beam or planks a large-sized machine is required. The owners of apartments with loggias will suit only a table mini-machine.
Cutting out the pulleys and attaching them to the supports
The diameter of the belt drive pulleys can be chosen freely, but the bigger the pulley, the longer and better the saw runs. The ideal ratio is 1/1000th of a blade to the diameter of the pulley. So for the 40 cm pulleys the strip should be 4 mm. But when operated correctly, even narrow pulleys can be operated safely with 6 mm blades.
The diameter of the belt drive pulley should be chosen according to the diameter of the main pulleys, belt length and engine speed.
Length of saw pulley circumference is calculated: L= 3.14diameter of pulley. 2. The average speed of the web should be 30 m/sec. 3. The number of revolutions is determined: O = 30/D; 4. The ratio (C) of motor revolutions (OM) to belt drive pulley revolutions is calculated: C = OM/O; 5. Diameter of the drive pulley = D/C.
Edge of the pulleys of the blade make convex, with an angle of 5-10 degrees. because of this the saw band is self-centered and does not fall down.
But it is better to make a shallow groove on the belt drive pulley where the belt will be located. Pulleys can be wrapped with ordinary bicycle or wheelbarrow tubes.
Diameter is chosen to be one or two sizes smaller than the pulley. This rubber banding prevents the web from slipping.
The upper pulley is mounted on a movable block, which should move horizontally, providing the belt tension.
A special lifting device is provided for this purpose. The easiest option is a bar located under the block and attached to the lever with a very tight spring. pushing on the lever, the bar raises the pulley block and provides the necessary tension.
Provide a way to secure the arm in a given position, e.g. with several bolts at different levels. A spring will provide the necessary pressure and at the same time dampen the tension, preventing the belt from tearing.
The lower pulley block consists of two pulleys attached to an axle. a driven pulley and a driven pulley.
It is important to properly balance the upper and lower pulleys in the same plane, minimizing the “figure of eight” when the wheels move.
Self-aligning bearings are great for mounting the top pulley, so you can put the wheels on or off very quickly.
But they need to be attached to the pulleys as tightly as possible, or the bearings will go loose very quickly. After the wheels are secured to the frame a test run of the saw with extreme care.
A will be needed
Using a wet polish on the finish, tidy up a piece cut from an old hacksaw blade, wiping it dry with wipes.
Clamp the workpiece in a vice with wooden plates and use a flat metal file to level an edge for cutting teeth, checking with a measuring tool.
We glue a piece of scotch tape along the machined edge, and over it a piece of marking paper and cut it along the contour of the workpiece. According to the markings we cut teeth with a triangular file and check them by cutting lengthwise through the wooden workpiece.
We separate two blanks from the brass band using a metal saw, clamp them one by one in a vice, cover the width part with a steel band and clamp them with clamps.
With the open part of the brass strips we remove the layer of metal with a file and a carbide scraper, the total thickness of which should be slightly less than the thickness of the blade.
Drill two holes in the brass blanks approximately in the middle of the sample at some distance from the ends. We put pins in them and place the saw blade into the slot until it stops in them.
Then we take out the pins and flatten one end with a hammer. Use clamps to clamp the shoe and the blade with the pins, and cut off the excess from above. Flatten the protruding part of the pins with a hammer on an anvil.
Using the template, we machine the workpiece with a drill and Forstner bit, a hacksaw, an axe, a plane, a chisel and a chisel until the required contour is obtained in outline. Finish the handle with a semi-circular rasp, an abrasive wheel and a semi-circular file.
Make the cut in the handle and sand it with emery cloth. We shorten the brass shoe at one end, and in the handle we choose a groove, where we insert one edge of the blade and shoe.
Drill two through holes through the handle, shank and blade with a drill bit with a refractory plate. Grind the handle with a fine sandpaper and wipe it with a cloth soaked in olive oil.
We put the handle in place, put the bolts with a semicircular head in the holes, tighten the spherical nuts on the back side and correct the teeth with a file.
Operating a handheld metal band saw
After the tool is made and tested, it is important to follow simple rules for safe use of the device. This is a guarantee of long machine life, high quality work, and saw safety for you
Tips for the craftsman
- Do not pull the workpiece backwards while working: this can cause the saw to jump off the rails.
- Use the feed board when working on small parts, it will protect your hands.
- Make sure it doesn’t rotate while making cuts in large structures.
- Keep chips and shavings out of the motor during cutting.
- Before you start using the tool, make sure it can be turned off quickly.
Be sure to follow safety guidelines
- During the first 180 hours of use the bandsaw is not designed for extreme loads: do not cut too hard materials or workpieces of maximum thickness.
- Every 2 hours of work it is necessary to make a break, otherwise there is a high probability of engine overheating.
- While working on a manual machine, it is necessary to use protective equipment:
- special safety glasses;
- Hat (especially with long hair);
- Wear tight-fitting clothing;
- Closed shoes with non-slip soles.
- In the process of work do not touch the saw blade, do not hold the workpiece in your hands, use additional supports, supports, fasteners.
- After finishing your work clean the machine from dust, dirt, oil, sawdust and unplug it from the mains.
We have considered the specifics of using different modifications of the tool, as well as their differences, understood the technical characteristics and the principle of operation of the machine. The many advantages of band saws make them indispensable when working with metal, including at home. It is not necessary to go to the store and spend money on an expensive professional model: for most work will do the classic band saw for metal, made by your own hands. Now you know the step-by-step instructions for making the machine, as well as the rules of its safe and productive use.
- Elements of the theory of the metal cutting process / A.М. Rosenberg, A.Н. Eremin Moscow
- The handbook of the young cutter / In.Л. Kosovsky М.: High School
- Welding, Cutting, Brazing of Metals Moscow: Mashinostroenie, 2005.
- Wikipedia article
How to convert office knife into a compact saw
It is not uncommon for do-it-yourselfers to have occasions when something needs to be sawn, and a full-fledged saw is not around. How to be? In this case, an ordinary box cutter will do the trick. True, slightly upgraded.
- Open the housing and take out the blade. One must act carefully to avoid injury.
- Put the blade on the table and a hacksaw next to it. Only a small part of it will be needed.
- Measuring out the right size on the hacksaw, focusing on the blade of the knife. This is done in order for the hacksaw to hide in the body without any problems.
- Make marks with a marker.
- Most often it is not difficult to break the blade. It is necessary to clamp in a vise and bend to the side. It is worth acting carefully, because at the moment of breaking it may happen that a piece of metal will fly off.
- If the hole in the hacksaw is round, it will fit perfectly on the knife holder and easily replace the main blade.
- Insert the hacksaw into the body and fold it back.
Now every home handyman has a homemade band saw, which can always be carried with him in his And if necessary, extend the blade by securing it with a latch.
The metal blade can be sharpened with emery paper for better durability. The renewed blade is guaranteed to cut everything. both metal and wood.
Drawings with the dimensions of the band saw
Before proceeding to the construction of the machine, it is necessary to find the appropriate drawings. Not only the construction elements of the band saw are marked on them, but also the dimensions.
The classic floor machine is about 50 cm wide
Knowing the dimensions of the future band saw helps to choose and clear in advance a convenient place for it in the home workshop.
Making a Karambit Knife From an Old Saw Blade
How to make the wood buzz saw comfortable and safe for work
When preparing the instrument for use, the following procedure should be followed:
- Insert the blade into the slots of the handles and secure it through the side holes with dowels;
- bring the saw to the chest so that the bowstring touches the body, and with one eye carefully study the position of the blade. It should be placed strictly perpendicular to the line of sight;
- Slowly and carefully turn the handles (it is the handle, not the blade)!), achieve an even position of the toothed blade in the fixing slots;
- Having exposed the blade, carefully rotate the arrow, twisting the bowstring and stretching the struts for a firm attachment of the blade.
Working blades for archer saws are not recommended for sharpening and dressing with your own hands. It is better to buy factory ones, which are distinguished by sharpness and accurately set “toothed” blades. Therefore it is forbidden to be distracted during any sawing, otherwise one can saw off his own fingers together with the board. If forced to interrupt to leave the saw sticking out in the workpiece is not recommended. a high probability of breaking the blade, and the work of such a position is more difficult to resume.
Before you begin, check your tool and make sure there are no cracks or damage to the wooden parts of the poles, and that the bowstring is intact. Carry the saw carefully, making sure to point the sharp blade down and back in the direction of travel (i.e. the bowstring forward and upward). Wooden workpieces should protrude (“hang off”) from the fixed support for convenient cross-cutting sawing. If you have experience, start the sawing process from the nail of the thumb of the hand that holds the beam or bar.
Making a Knife from an old Saw Blade
When the blade has “gnawed” into the wood, it is no longer resting lightly on the fingernail, but on the joint of the thumb. However to improve accuracy of cuts (and for any curved cuts) it is necessary to use templates or a jigsaw.
For longitudinal cuts, the blade is clamped at an angle of 0˚ to 90˚ in relation to the horizontal post. force applied will be lower than for cross sawing, so the process will take more time, it can be done with two hands. It is a good idea to lay the board or bar horizontally and pull the saw toward you by holding onto one of the handles and the side post. If you want to make a curved cut, it is not enough to choose a blade of narrow width (6 to 8 millimeters).
Blades for curved cuts should have rectangular teeth and a considerable pitch. up to 2.5 nominal of nominal blade thickness. When it is necessary to saw a solid board with many knots, beveled layers of wood, etc.п., choose the widest hacksaw blade (up to 5 cm). Its pitch should be small, but its thickness is considerable. Curved and curved cutouts on problematic boards are not recommended.
Layout of band saw
The band saw machine is characterized by high versatility. It is possible to saw wood and metal:
There are machines with the feeding of the working console, when the material is fixed still and the blade is pushed over it, and there are built on another principle. the saw unit is stationary, and the log, plank or metal sheet is fed. The second option is more accessible for self-made.
The main components of the band saw:
- Heavy and sturdy frame. It should ensure the stability of the machine during operation and absence of vibration;
- Working table with a stop and a ruler;
- Driven pulleys;
- Motor (from 2 kW);
- Control panel;
- The lubrication system;
- Protective casing.
It should be remembered that the cutting speed of different metals is somewhat different. The range is very broad. from 30 to 100 m/minute. averaged rates of cutting speeds of homogeneous solid metals are given in the table, but for each particular model of saw and band saw they may differ within the range of 10-15%.
If the middle of the metal blade is damaged, do not throw it away immediately. After all, the edges can still be put to work. The best solution is to cut the damaged piece into two parts. And it is there to make a hole for the holder of the blade body. That way the part that is sharp can still be used for a long time.