Tensioning recommendations for the band saw blade
One of the factors affecting the proper functioning of a band saw is the tensioning force. Tensioning is effected by an idler pulley, the longitudinal movement of which is effected by a tensioning unit.
Depending on the model of the band saw, the tensioning unit can be of different design, but the most common are screw-driven and hydraulically driven units. Regardless of its design, the tensioning assembly must ensure that the required tensioning force is always the same and constant, both during the sawing process and with each installation of the saw.
Minor deviations of ± 10 % from recommended values are permissible. It should be understood that improper saw tensioning can significantly affect the life of the saw. Thus low tension leads to deviation from kerf perpendicularity or jamming of the saw in the workpiece, high tension. to formation of cracks and fracture, as well as significantly stresses the components of the tape-drawing mechanism of the machine.
Checking the tensile force with a tensiometer (see drawing on figure 2). fig.1).
Procedure for measuring the tensioning force of the band saw blade with a tensiometer: 1. Switch machine off and secure it against unintentional restart. 2. Insert a new band saw on the machine. 1 Check if the saw is lying correctly on the belt pulleys as far as the flange. 3. Place the tensiometer on the horizontal arm of the band saw, between the movable and the fixed guide post. 4. Fasten device to the saw. 5. Align the “zero” position of the indicator scale with the position of the arrow (see “3. fig.2):
“Zero” position of the tensiometer indicator hand
Tension the band saw. The arrow on the gauge shows the actual force. 7. When the desired value is reached, stop tensioning the saw and remove the tensiometer (see 3). fig. 3):
Required value of blade tension
However, not all machines are equipped with a means of tension control. And even those with gauges of various kinds need to be checked periodically for proper readings. Therefore we recommend the use of WIKUS strain gauges, which you can obtain from our company. Our specialists will give you a proper instruction of how to use the machine and will give you the necessary recommendations for band sawing.
Choosing the right lubricant for the band saw blade.
Never use water as a lubricant for band saws. Water is not a lubricant and should not be used for many reasons. Not only is water unacceptable as a lubricant, it also causes rusting of the blade, causing corrosion, and inadequate swelling of the chips. This prematurely destroys the body of the band, and the recesses between the teeth of the saw. Water is also wet tires or V-belts. No need to lubricate the blade if the resin does not stick to the saw blade. If sticking does occur we can suggest the following: Mix high-adhesion chainsaw oil in half with kerosene or diesel to get the right lubricant. Spray mixture on both sides of the blade every four minutes while the machine is in operation. After lubrication the sawing noise is reduced by more than 50%. Don’t put grease on until the noise starts to get worse. You have to lubricate both sides of the saw. Lubricating the blade increases the life of the band by more than 30%. Sparingly applying the lubricant allows you to cut high-grade lumber without getting it dirty; we also believe it extends the life of the rubber seals.
When you are finished, remove the tension from the saw. The band saws always heat up and lengthen and then shorten as they cool down during each cool-down period. Therefore the saws left on the pulleys when under tension overload themselves and the two pulleys become imprinted, causing cracks in the troughs between the teeth. When you leave a belt on the machine under tension, you not only deform the rim and surface of the belts (which makes them very rough), but you also put excessive stress on the bearings and shafts. Believe it or not, you can sooner or later damage the geometry of pulleys and greatly reduce their service life. You are also destroying your rubber gaskets and V-belts.
Sometimes there is confusion about the difference between borazon and elbor.
Borazon, a technical cubic boron nitride (b-BN), was first produced in 1957. In 1969, General Electric registered the trademark “Borazon” for crystal.
Elbor. technical cubic boron nitride (b-BN). Elbor was synthesized in 1959 by a team of scientists from the Institute of High Pressure Physics (IPPP) of the USSR Academy of Sciences. Since 1964, industrial production of elbor and elbor tools has been organized.
So it is the same material, but produced in different ways in different countries. Russian elbor is considered to have the best grinding properties by its structure.
To date, working with discs from different companies, we have received an average resource:
I want to repeat what I started this article with. Any machines are bought to make a profit with them. Everyone wants to put the equipment in and work without too many problems. But very few people really know what they have to deal with after installing the basic machine. After reading this article, you got a complete picture of the pros and cons of the two methods of band saw sharpening. Now on the basis of this knowledge you will already be able to make a competent choice yourself.
We suggest you buy a trial batch of band saws with subsequent sharpening in our service center, it will give you an understanding of how the band saws work after sharpening with a Borazon wheel, compare them with your sharpening and not buy an expensive at first glance and modern machine.
The finer points of band saw setting
As the tool is used, the quality of its cutting edge deteriorates. So setting and sharpening band saw blades correctly is a natural part of the cutting process.
Please note! Deburring should be done before sharpening, not after!
Turning is the operation of bending the teeth to the sides to prevent the tool blade from clamping and to reduce friction. There are three basic types of resharpening:
classical. each tooth is bent to the right and left side strictly alternately; deburring. every third tooth is left in its original position. “topical for tools used for cutting especially hard materials and alloys; wavy. each tooth has a “different” value of bending, so they form a wave. This is the most complicated type of setting.
It is worth knowing! When bending out, not the whole tooth, but only a part of it. one-third or two-thirds from the apex.
Manufacturer’s recommended values of the pitch are within the range of 0.3-0.7 mm. The operation should be carried out with a special separation tool.
Advantages and disadvantages of band saws
This type of saw is successfully used in various types of work with wood and other materials and has a number of advantages:
- it is economical to use the band model because it makes very narrow cuts;
- high productivity of the device due to the fast sawing speed;
- the moderate cost of the device is available due to its specific structure;
- does not produce a lot of noise when working, which makes it more comfortable.
Along with numerous advantages, band saws also have some limitations and disadvantages:
- complicated process of setting the parameters of the device, which can be a problem for a beginner;
- Due to the nuances of the mechanism design, it can only perform a longitudinal cut of the wood blade.
Cost and effectiveness of industrial designs
Why there is a great desire to create a self-made version of the machine? An example can be called a band sawmill “TAIGA”, Even the simplest version of the design, which does not have a large capacity, will cost at least 90 thousand. Self-made band sawmill will cost many times cheaper. A self-made machine is suitable for occasional use.
Difficulties in making the sawmill yourself
The design of a band sawmill is quite complex. The quality of the assembly depends on the performance of the band saw, the service life without breakdowns and much more. You should start making your own machine after considering the following points:
- Installation work is carried out using welding. Therefore, without a welder to work on the frame and other elements is almost impossible. To change the shape and size of the elements of the construction you will need an electric tool and a milling machine. Of course, the creation of some elements can be entrusted to professionals, but this will significantly increase the cost of the work.
- During the work on the band saw is a heavy load. That is why the construction must be stable and firm. To do this, the structure is attached to the base, and the frame and other elements are made taking into account the possible weight of the processed logs of about 300 kilograms.
- If a homemade gasoline band saw is created, then it is necessary to take into account the need to work on sharpening the saw and setting the working part.
- There are quite a few different designs that allow you to specify the thickness of the resulting products.
- Consideration must be given to the safe use of the equipment. Installed saw and band saw can cause significant harm to human health.
It is worth bearing in mind that the design of homemade band saws is only suitable for cutting boards of different lengths and widths.
How to Tune Up and Maintain Your Band Saw
There is a fairly large number of designs of homemade band saws, the drawings of which are based on the use of electric and gasoline engines. At the same time, electric versions are very popular because of the best performance and ease of use. But not in all cases it is possible to use an electric motor as a driving force, since not all plots of land have electricity.
Carry out a review of specific machines, the drawings of which have exact dimensions. After all, each production requires a table of different sizes, as well as an electric motor of different capacity.
Tool for making band saws
To assemble the band saw at home it is worth preparing in advance. Experts recommend having such additional tools:
Now it is possible to describe the band saw making with our own hands in more detail. The following procedure should be followed in the work:
- Before assembling this machine at home, it is worth to find good and detailed drawings of the machine. They are the main element of quality manufacturing. The work begins with the construction of the cabinet and table. On them will be fixed all the mechanism of the machine. Wood or plywood board comes in handy here;
- Then it is worth to cut out of plywood special pulleys, which are pasted with sheets of rubber. The wooden parts should be well sanded and treated with resin;
- then the frame for the whole machine is made. It is worth calculating its shape in advance to ensure a secure hold on the cutting belt. The supporting frame is welded from a channel and the axle of steel is put on;
- the pulleys must be put on the axle with the help of special bushings, placed on its different ends. All pulleys must be sure to be properly balanced;
- So that the band is not subject to vibration, it is worth using a damper;
- To the electric motor it is necessary to connect all the parts that will be driven;
- it is additionally worth to make a guiding mechanism, which will help to feed the material for processing. It is made of metal corners.
How to tune a band saw for wood
Why to split the wood?
The simplest answer is to get the most out of your workpiece. For example, instead of planing a 25 mm board to 10 mm thick, planing will produce two boards of the same size from a single board.
As an additional advantage, each of these boards will have almost the same fiber pattern, which will allow you to let them for furniture lining (photo on the right).
And if you dissolve the 2 5. mm board of expensive wood into sheets of veneer with a thickness of 3 mm, it will save even more.
It is not always possible to predict how symmetrical in pattern the sawed panels will be. In principle, any wood fiber pattern has the potential to create a beautiful pattern, but choosing a blank with a particularly interesting pattern often yields the best results. See what was hiding inside the unsightly board I used to test the band saw adjustment.
Note. A band saw is when the wood is cut along the grain, parallel to the plate.
I first saw a cabinet with a symmetric pattern on the doors in a museum, at the XVII-XVIII centuries’ furniture exhibition. After examining these nearly identical panels with a mirror-like fiber pattern, I was blown away by them. In those days I had an old Craftsman band saw in my small basement workshop.
Its one-size-fits-all blade was good for making acceptable curved cuts, but was not well suited for precisely sawing along the grain, which I now planned to do.
And frankly that saw needed more than just a new blade to work accurately and consistently. I later learned many lessons about how to handle any band saw.
To set it up correctly the table must first be set perpendicular to the blade, get maximum kickback from the guide rails and make sure the kerf is in the right direction.
Tools for home and garden, crafts, etc. the are very low
Get a blade with a more aggressive cut. A blade with three teeth per inch and more recesses between them is better at removing sawdust, which can cause the cutting blade to bend and twist.
Keep the workpiece firmly pressed against the guide and against the table.
A special pusher transmits the necessary clamping force to the guide rail and allows your hands to stay at a safe distance from the blade as it disengages.
Once the band saw is well set up, you need to pay special attention to the saw blade. Wide boards require a blade that cuts evenly through the thickness of the piece, removing a lot of sawdust. The wider the blade, the straighter the cut, so try to use the widest blade that fits your saw.
Place the square 6 mm away from the saw blade (it may be necessary to raise the blade guard to put it in place) and press with your finger to the center of the blade. A moderate amount of pressure should bring the blade into contact with the angle.
In this photo, the saw blade is too far back on the top drive wheel: so the kerf is deflected toward the guide.
If, on the other hand, the blade is too far to the front edge of the wheel, it has the opposite effect.
Most band saws work with at least 12 mm blades and many work with even wider blades.
Generally a wide blade with three teeth per inch (3 tpi) length offers the ideal combination of an aggressive but smooth cut with active sawdust removal, which is what you need when you are sawing wood. Finally, let’s talk about the rails.
The workpiece to be sawn should be no more than twice the height of the guide. So for example a 100 mm guide would be suitable for boards 200 mm wide. If you need greater height, use a saw guide made by yourself.
Tapping wood: Ready, steady, set, go!
Start by giving your workpiece a rectangular shape and cut a similar-sized piece of wood.
Make sure it is lying flat on the saw table and fits snugly against the guide rail, and then adjust the settings on the band saw.
Adjust the fence to the desired cutting thickness and slowly feed the timber under the saw blade. The saw motor should turn smoothly without jamming. At the end of the sawing advance the workpiece with the pusher. Then examine the sawn piece.
Angle the guide bar as needed to align the kerf. The adjusting bolt on the guide makes this easier. You can also use magnetic guides (e.g. Carter Magnafence: carterproducts. they make such temporary adjustments much easier.
If it appears to be thicker at the top or bottom, check the setting of the saw table strictly at 90° to the saw blade and adjust it if necessary.
If there is a depression or bulge in the material, the problem might be insufficient tensioning of the saw blade. On many saws the integrated tension adjusters are not very accurate.
Here is a perfect example of a symmetrical fiber pattern. These panels make any piece of furniture much more attractive than two simple thick panels of different boards.
A properly tensioned blade or blade should not deflect more than 6 mm when pressed in the middle (photo above left).
How to Tension a Bandsaw Blade with the Deflection Method
Feeding too fast under the blade, using narrow blades with too many teeth, or using blunt blades can also cause this distortion in the cut. If one end of the sawed off part turns out to be thicker than the other, the problem lies in the displacement of the blade, that is, the blade deviates from the parallel with respect to the guide.
If the blade is sharp, guides are installed correctly, feed speed is correct, but the problem is still not solved, try to adjust the slope of the upper drive wheel so that the saw blade passes strictly in the center of both wheels (top right photo).
Victor: “I own a joinery workshop, the jigsaw broke down a year ago, and the store assistant at the store recommended a compact band saw instead. Cutting is straight, no wiggle like a jigsaw. Productivity increased many times over. Excellent equipment!”
Eugene: “I make office furniture. The Makita band saw has been faithfully working for five years now, during this time it has never broken down. Now I recommend only this model to all my friends.
Ruslan: “I bought a budget band saw machine to make custom home furniture. With its help I quickly make shaped furniture, which is in demand. Working with the machine is a pleasure.