Owners of suburban areas and summer residents who like to engage in craftsmanship and manual work often have to deal with wood. It has always been considered one of the most popular DIY materials. Even today, when manufacturers around offer various composite, synthetic materials, wood remains relevant.
In order to make a band saw with your own hands, you will first have to master the frame construction scheme. For its construction, it is worth choosing a fairly hard wood.
The main components of the frame:
To make a makeshift frame more stable and stronger, you must first prepare a drawing, according to which the entire structure will be produced. Drawings are best done in detail, but with some knowledge you can get by with a schematic representation of the design. It is important first of all to calculate the optimal length of the canvas, the remaining dimensions can be adjusted.
It should be borne in mind that the finished band saw is quite high and requires certain conditions in the room where it will be installed.
Therefore, you need to calculate the optimal height with the possibility of installation in the workshop or other place where it will stand. It is also recommended to choose a tabletop height convenient for a particular master. The working surface (countertop) can be made from ordinary plywood.
The main structural support bar can be made of a solid beam, for example, maple or other wood.
In order to give additional stability to the frame, it is edged with rails. In some cases, even parts from old furniture can be used.
The diameter of the pulleys should be selected so that the structure is not too bulky, but at the same time provides a sufficient speed of movement of the canvas.
Pulley bar and bearings
The support bar must support 2 pulleys. bottom and top. Therefore, it is better to make it from a bar with a section of 80×80 millimeters or thicker. The wood must be strong, dry enough.
Bottom and top of the rod are mounted supports under the pulleys. Such supports can be made of different materials. One option is reinforced plywood of several layers. Both supports should be at a sufficient height from each other so that the largest logs with which the work will take place can pass through this distance. It is better to leave some stock with the prospect of future use. The axles of the pulleys are selected based on the characteristics of the blade and the motor, as described below.
The main requirements for a work surface are its optimum height. Work at the countertop for the master should be convenient, so it should be high enough, but not too much.
You can also know to make a countertop in the form of a closed cabinet, then it will be able to accumulate sawdust remaining after processing the logs. To make cleaning the sawdust collector easier, you need to make the table in such a way that access to accumulated waste is open, for example, using the door.
The tabletop in a wood band saw is usually installed on the lower support of the rod and additional supports, in some cases you can do with a simple additional support or supports connected to the rod. The main thing is that the weight distribution is optimal and the countertop does not roll over.
Pulley selection guidelines generally relate to their diameter. It is better to use large pulleys, as this guarantees a longer life for the saw. The thickness of the web will also depend on the diameter of the pulley. Typically a web is used that is 1000 times smaller than the diameter of the pulley.
Video: How to Make a Band Saw on a Tree
Thus, for a 35-centimeter pulley, a canvas 3-4 mm thick is suitable. Experts say that in some cases it is possible to take thicker canvases (for example, up to 5 millimeters in this case), subject to proper operation.
In addition, you need to choose the right pulley for a belt drive, and this depends on the size of the main pulleys, the engine speed in revolutions per minute and the length of the blade itself. Calculate it as follows:
- First, calculate the length of the outer side of the circle C, for which its diameter D is multiplied by the Pi number (3.14): C = 3.14D.
- It is taken into account that the optimal speed of the saw should be about 28-32 meters per second (take an average value of 30).
- The number of required full revolutions per second is determined by dividing the number 30 by the obtained circumference O = 30 / C.
- After that, you need to calculate the number of gears that are received by dividing the engine speed W by the desired number of revolutions of the pulley O: K = W / O.
- The gear ratio K serves as a divider to determine the diameter of the drive pulley, that is, the diameter of the drive and working pulleys is related to the same number K: d = D / K.
Pulley rims should be convex with a curvature of up to 10 degrees. This allows the canvas not to fly, focusing on the circles. On the contrary, a small depression is prepared on the drive pulley so that the rubber does not slip out.
The manufactured pulley and its edge are usually tightly fitted with rubber, for example, from a bicycle wheel (camera).
In order for the web tension to be optimal and adjustable, the upper pulley is usually mounted on a block capable of moving in the horizontal direction. To do this, use the mount using a spring and a lever that acts on the unit, lifting it. This ensures proper depreciation and lack of returns. In this case, the lever must be fixed, for which use bolts at a certain height.
In the lower block there are two pulleys at once. the so-called driven and leading, which are located on 1 axis and are rigidly fixed. If their diameters differ, then the diameter of the driven pulley must be taken into account in calculating the number of gears instead of the drive, because since the number of revolutions is the same for them, the gear depends on the diameter of the pulley directly interacting with the motor.
When installing the upper and lower blocks, it is extremely important to install the pulleys under the canvas in the same plane. In this case, imbalance in the movement of each of them should be avoided. They should spin softly and smoothly.
Sometimes a bearing is used for the upper block, which helps to center, making it easier to put the circle in place and remove it.
To ensure that the home-made band saw does not break, and the tape does not slip out and pulled out of the pulley under pressure, guides are installed under the blunt edge of the saw. This is usually done using roller bearings that are mounted on wooden slats or bars. In this case, the bearings must both guide the tape from the sides and keep it behind.
The installation of a bar of guides is best done at the highest tension of the tape, choosing the best place for fastening the bar itself. This will avoid deviations in the course of work.
Sometimes, instead of bearings, wooden bars are used. For any type of rail, a good addition would be duplication of the rails from below under the countertop.
To avoid even the smallest deviations during the operation of the saw, the guides should be installed as close as possible to the workpieces. The best option for guides is a design with removable bars and their adjustable height.
End of work
From above, the pulley should be closed with plywood, which will save the canvas when it falls. Due to this, the saw lingers in the case and does not injure those working at the installation.
If the bottom is equipped with a collection box for sawdust and shavings, then it is better to place a bucket in it or make a separate container to make it easier to get rid of waste.
It is imperative to protect against the transmission of various wastes on the transmission belt. In order to do this, it should be brought out, away from the table, while closing it with a protective casing. The same must be done with the engine to prevent its pollution.
Wooden surfaces can be treated with paints and varnishes. This will help the tree be in operation longer, and will save the hands of the master from splintering. Impregnation pretreatment, grinding and antiseptic are welcome.
Such a band saw will last a long time and help to perform a wide range of work. The main thing is to comply with safety rules, do not drink AL-Kol before work and so on. Then the woodwork will turn into a useful, effective and enjoyable activity for any craftsman.