Not a single industrial complex for cutting and logging, as well as for metal processing, can do without such a tool as a band saw. But not every owner of this tool knows the intricacies of the choice and the main manufacturers, which is why many acquire devices, which subsequently reveal many shortcomings.
The device for working with metal
All tools for carving are divided into several types, but the main and most convenient is the vertical type. It is such a machine that allows you to move the workpiece during operation, while other types firmly fix it.
The main classification divides the devices according to the material for which they will be used:
- For metal carving.
- For processing synthetic materials.
- For wood.
- For a stone.
And also the tool is divided according to the teeth. Here, strips with an unhardened tooth stand out, which differ in a rather low cost, but operate with a minimum feed speed of about 7 meters per minute. Tapes with hardened teeth have high wear resistance and a higher feed rate, but such a device is more expensive.
Instrument Selection Rules
In the arsenal of each sawmill and workshop there are band saws for metal. How to choose a quality device:
- First you need to choose two or three companies that occupy leading positions in the market and are distinguished by their reliability and quality.
- An important place is the ratio of price and cost of maintenance. The device in the first place should be flawless, easy to sharpen, easy to saw material.
- The number of teeth. Experts recommend purchasing saws, the number of teeth on which is a multiple of three. It is such devices that ensure the normal and long operation of the tool.
Major manufacturers of saws
The top position in terms of price and quality is taken by Simonds tools. Saws are made in the USA from a patented carbon alloy, which, unlike other canvases, is heat-treated twice, which makes it very durable. The company monitors the quality of each device by scanning to identify cracks.
Another company that has established itself on the market is Wood-mizer, which manufactures devices for different conditions. The first variety is standard saws. But even this type of tool has its own characteristics, namely Wood-mizer makes the teeth stronger with the help of electromagnetic induction, which allows to increase the gap between sharpening. The company also produces tools for industrial enterprises and for cutting heavy-duty metals and wood.
Arntz is a famous German company that has gained popularity around the world. Saws of this brand are made of materials containing cobalt, which makes the tool strong and wear-resistant. A feature of this brand is that the saw has a function of increasing speed.
Homemade metal saws
Making a metal band saw yourself is also possible. A homemade device has its drawbacks and advantages.
The advantages of such an apparatus include the low cost of manufacturing and using the created tool.
The process of creating a tape apparatus includes several stages. First you need to make a frame that will support the entire structure. It can be made of any material, but, in terms of cost, the most budget option is a wooden frame.
The next part of the tool is the block of the upper pulley, which, when vertically moved, will provide tension to the blade.
The saw table is mainly made from plywood. For more convenient use, you can make the table rotary.
Cloths and sharpening apparatus
The blade for making a saw at home can be purchased in several types:
- Bimetallic blade, which is used mainly for cutting very strong metals and alloys.
- Diamond is used for processing granite, quartz, marble, as well as other hard materials.
- For small workshops where they work with fragile materials, tool steel canvas is best suited.
So that the tool made does not become dull and always remains a faithful assistant to the master, it must be properly prepared for work. Sharpening of band saws for metal is one of the most important stages of working with a tool. Depending on the teeth, grinding wheels are made of different materials and shapes.
In order for the sharpening to be of high quality, it is necessary to carry out the procedure on the front surface of the tooth or immediately involving the back and front surfaces.
Attentive to the choice of the tool, as well as when used correctly and sharpened in a timely manner, the device will serve its owner for a long time.
Band saws are powerful and reliable tools that are actively used in the construction industry and are used for cutting various materials. In order to avoid problems during operation, it is necessary to carefully choose this type of equipment, given its technical characteristics.
What are band saws and what are its features, we can find out if we familiarize ourselves in detail with the technology and a number of features.
Band Saw Design
- Band Saw Preparation
- Features of the use of band saws for wood
Shapes and sharpening angle
- Divorce Recommendations
- Sharpening recommendations
Band Saw Design
The band saw belongs to the category of cutting tools and is an integral part of specialized equipment for wood processing. It is a closed tape connected by a weld (Why saws are torn on a tape sawmill). And on the outer edge of the tape are the teeth.
The choice of thickness of band saws is determined by the stresses that occur in the blade during operation: from centrifugal forces, bending on pulleys, tension; cutting resistance forces; heating the blade in the cutting zone; pulley inclination, etc.
With a decrease in the thickness of the band saw, the waste of wood into sawdust is reduced by reducing the width of the cut, however, this increases the likelihood of loss of stability of the saw in operation.
Band saws for sawing wood on joinery and dividing machines are made according to GOST 6532–77, and for sawing logs and beams according to GOST 10670–77. The saw blade is characterized by thickness S, width B and length L.
For production, special alloyed steel grades are used. 9HF, B2F or C75. In the manufacturing process, the teeth are treated with high-frequency currents. This increases their hardness. It is this fact that affects the separation of cutting edges and maintainability. Often, several types of steel are used in the manufacture. The main tape is made of spring, and the cutting part is made of steel with a high content of tungsten or cobalt.
Flight saw preparation
When preparing band saws for work, the following operations are performed: marking and trimming the tape along the length; connection of the ends of the tape, dressing and rolling of the saw, sharpening and spreading of teeth, installation of saws in the machine. The tape is marked on a workbench, the tape is trimmed with scissors, and the ends of the tape are welded.
Butt welding of tape ends is performed on welding units: ASLP18, ASLP35. After welding, the junction in the unit is tempered to give the fabric the necessary hardness and viscosity. The seam, after connecting the ends, is stripped and aligned to the thickness of the web.
Features of the use of band saws for wood:
- Requirements for wood. The harder it is, the faster the blade becomes dull;
- installation conditions. Be sure to observe the indicator of tension. If it is less than required, sagging will occur. With strong tension, the probability of breakage of the web will increase;
- periodic sharpening. This will require a special machine.
The implementation of the last paragraph will increase the life of the tape structure. However, sharpening yourself is problematic. you need to select the correct wiring, observe the angle of blade processing (Sharpening of saw blades).
When buying a used saw, you need to pay attention to the presence of repair welds on the blade. They indicate frequent instrument breakdowns, as well as the fact of metal weakening and the presence of microcracks on the instrument, which are not amenable to visual inspection.
Shapes and sharpening angle
At the first stage, the type of band saw is determined. The main indicator is the shape of the teeth. Depending on this parameter, they are divided into dividing, joinery or intended for sawing logs. The initial geometry and wiring angle are determined by the manufacturer. It is recommended to find out these data at the stage of procurement of components. They are needed to determine the parameters of the machine (Grinding machines).
Video: Saw Wood Grade Steel
For hardwoods, the rake angle should be minimal. This ensures optimal contact of the processing material with the metal. If you plan to process soft varieties. to increase the processing speed, you can use models with a large value of the rake angle.
The determining parameters for self-updating the cutting edge are:
- Tooth pitch. This is the distance between the cutting structural elements. Frequently encountered values are 19, 22 and 25 mm;
- tooth height. Magnitude from its base to the top;
- angle. The main value that you need to know to form the cutting plane. For carpentry models, it is 35 °. In dividing saws, the angle is from 18 ° to 22 °. In structures for processing timber. 10 °.15 °;
- divorce. Determines the deviation of the tooth from the general plane of the blade.
After performing work on the machine, ideally, these characteristics should remain unchanged. For each model, the manufacturer determines the maximum deviation value. If during operation it is achieved, it is necessary to purchase a new model.
Before forming the cutting edge, the correct tooth alignment should be made. Throughout the entire period of operation due to constant loads, their location may change. Therefore, the geometry is first adjusted, and then sharpened.
The angle should correspond to the original angle. The type of wiring is also taken into account, which may be as follows:
- Classical Alternate bending of the teeth relative to the blade to the right and left sides;
- cleansing. The first and second teeth deviate to the right and left, and the third remains unchanged. This technique is used for saws that are designed to handle hardwood;
- wavy. The wiring angle for each tooth is individual. As a result, they form a cutting edge resembling a wave. The most difficult type of wiring.
The right choice of the type of grinding wheel is important. It must match the grade of steel of which the band saw is made. For tool steel structures, corundum circles are used. If it is required to improve the cutting properties of bimetallic models, elbor or diamond wheels should be used.
Depending on the technical capabilities, it is possible to carry out full-profile processing or each cutting part separately. In the first case, you need an elbor circle, the end of which has the same shape as that of a saw. For the second option, the processing of each tooth is performed.
And finally, we will indicate several manufacturers of band saws:
Forest Master XLC. teeth are hardened, sharpened, bred.
TTH (ready to work). sharpened, divorced.
(profiled). not sharpened, divorced.
From the side it seems that making a knife is easy, that it is only a sharpened steel strip and a wooden handle. But when it comes to practice, the picture changes dramatically. The main thing in this process is knowledge and experience. When you know, everything is simple, when there is no experience, everything is complicated.
Recently, I posted on the Internet a photo with seven blades made in one day in a Stakhanov rush.
Alexander Kudryashov in a comment asked me to tell you how I make smooth and symmetrical descents.
In response, I joked: “It’s simple: you take a“ magic marker ”, draw smooth descents, pronounce wonderful words, and smooth descents are ready.”
But is it really a joke? A joke, of course, but the truth is somewhere nearby.
Later, I proposed to come and see in practice how to make the right descents and the whole knife. And this proposal was accepted.
According to my idea, Alexander should have been a bit involved in manufacturing himself: to choose a blank for the blade, material for the handle, the preferred length of the blade and handle. From our experiment, Alexander had to leave with a ready, solid, and most importantly, a working knife.
Alexander came smartly dressed in light sand-colored trousers and a coyote-colored fleece jacket, which was completely unsuitable for the work ahead. I had to give him work pants and a camouflage shirt in case he got dirty. Everything went perfectly. we are of the same size.
In the workshop, they went according to a predetermined plan. As a material for the blade, an old kind mechanical saw from a quick-cut was chosen. Why?
This is a well-known and repeatedly tested steel for industrial hardening. Yes, it is difficult to process, but due to the red resistance (ability to withstand heating for a long time without reducing hardness) it does not require cooling.
The thickness of the saw is 2 mm, this is enough for most working knife tasks. Knives made of mech saws are light, hold sharpening well and, importantly, are completely legal: the small thickness of the blade sweeps away any suspicion of involvement in knives.
In general, there are many brands of high-speed steels, but the manufacturer does not always indicate a specific brand, often limited to the HSS (high speed steel) brand. New saws are rare and more expensive.
For the knife maker, the novelty of the mech saw is of no importance, therefore, for the manufacture of the knife, you can use either a new saw, or pretty worked and even broken one. The result will not resemble the source material. Among the disadvantages, one can note the tendency of steel to spall under lateral loading and its susceptibility to corrosion.
Alexander chose a suitable saw blade from a quick cut (HSS made in USSR). I cut off the excess and on the emery made the contour of the future knife, then processed the workpiece with a kratsovka. a rotating steel brush, giving it a noble black shine, and painted the blade part on both sides with a blue wide marker intended for warehouse work.
Using marker paint, the caliper marked the lines of future descents, paying special attention to the synchronism of their exit to the butt. The resulting lines were circled with a “magic marker” with silver paint, which is nothing but aluminum powder in a polymer binder.
Why to them? Very simple. This paint withstands high temperatures, lays well on metal and holds firmly. The paints of ordinary colored markers during metal processing burn out, are erased, and crumble. A silverfish holds. That’s all the magic.
I installed the blade on a special device for launching descents (a cheaper version of the devices from Chapay, made independently from a steel corner). He marked with a marker the place where the descents will begin, and fixed it with a manual vise.
I performed roughing of the metal with a yellow cubitron II from 3M with P24 grain on a machine with an abrasive belt (on the grinder). For uniformity, I began to remove metal from the mark with a marker at the future handle and moved to the tip with uniform gentle pressure.
At the same time, it is very important to apply the future blade evenly, parallelly, without distortions. I gave Alexander a little stand at the machine at the initial stage, using special tools. Finding slopes is a process that requires experience.
Before I reached the silver lines of the “magic marker” a little, I changed the tape to P60 abrasive and began to level the line of the slopes. He made several movements from the tip to the handle, creating a right angle at the beginning of the descents. Then work began on the risk of descents.
To do this, it was enough work on abrasives P80 and P120. It is unreasonable to use P180 abrasives and finer for very hard high-speed steels. This is not Cubitron II, and abrasives do not work well for such tight steels. It is important that the finish processing of the blade was performed on the same tape, otherwise the sides will look different.
A knife from a quick cut does not require constant cooling during processing, and this is one of the pleasant moments in its manufacture. Of course, the knife should not be overheated, because the elevated temperature of the steel leads to the rapid clogging of the abrasive with sticky particles of metal. to salting.
Excessive metal pressure to the abrasive is undesirable for the same reason. A tape clogged with metal, which is no longer "nibbling" but "licking", can be refreshed. To do this, remove the clogged, lined tops of the abrasive and free the grains lying deeper.
It is easy to do. It is necessary to take a quick-cutting blade of a chainsaw and easily, like a file, draw it diagonally towards a moving tape at the bend (on the contact roller). This action will not give the abrasive primordial aggressiveness, but will refresh it and allow it to work more.
After the first side was finished, I turned the blade on the fixture on the other side, fixed it and took up the second side. It is always more difficult to do it, because you need to be the same as the first.
In addition, the workpiece is visible worse, warms more, and contact with a massive device that performs the function of a heat exchanger is no longer so tight. However, the blade was ready.
On a felt circle with a polishing paste, I corrected the traces of metal runaway. Once again I want to recall that it was high-speed steel, the hardness of which does not suffer from heating.
Having marked with a felt-tip pen a place for two holes on the shank, I drilled them with a six-millimeter feather drill for tile. I must say that on the first of these holes the drill has exhausted its resource (it was about the 50th hole).
Without the slightest frustration, I pulled out another cheap pen drill from the blister, drilled the unfinished first hole and drilled the second in 40 seconds. Then, with a larger diameter carbide-tipped drill, he chamfered the holes.
And then there was lunch. Having eaten with chicken, cooked by a beautiful wife, we started making a handle. For the handle, Alexander chose the rosewood.
I cut the workpiece on a band saw to the specified dimensions, attached a shank to it and drilled the first hole in a wooden workpiece with an ordinary drill. I inserted a six-millimeter pin into the hole, put a shank hole on it and drilled a second one. He marked with a marker where the edge of the shank will be in the handle, and he started marking for a future slot under the shank. Sawed under the shank performed on a band saw.
I know that a particular blade makes a cut of 1.5 mm wide. But I needed a cut under a shank of 2 mm thickness, so I inserted a sheet of cardboard folded in half to the left of the workpiece with a total thickness of 0.5 mm and sawed the slot to the required width.
After that, I began to shape the workpiece into a handle. By design, this was the straight handle of a universal knife, representing an octahedron in cross section. This was not my first knife with an octagonal handle, which looks strict, but grasped, very comfortable and does not crank in my hand.
I did all the work on the grinder using wood tapes. I set the necessary facets and took up the elimination of risks with a decrease in the abrasive grain. In the end, I already manually smoothed everything with an abrasive scotch tape, similar to a hard flat washcloth.
And now it’s time for installation. Measuring the thickness of the handle at the installation sites, I added 2 millimeters and cut off pieces of a tube of a given length with a small pipe cutter. The blade shank inserted into the slot of the handle. He walked with an interference fit, so he even had to use a manual rack press (up to 600 kg).
The press gently pressed the tubes into the handle through the shank through. Then he took up the direct expansion.
I took out a set of shiny balls from bearings of different diameters, put one small ball on the lower platform of the press, and the second on the upper cut of one of the tubes and stretched the edges of the tube. I did the same with the second tube.
I performed this operation with a gradual increase in the diameter of the balls. Now it remained to do the finishing operations of flaring with a jewelry hammer with a polished brisk.
A can of natural beeswax has already been warmed up in a water bath. The knife handle went into wax for impregnation and subsequent cooling. Beeswax is a natural food grade polymer. A tree impregnated with it does not accept moisture and does not slip in the hand.
In my kitchen, all knives are waxed and nothing is done. In wax in a water bath, you can hold the knife as much as you like. at least an hour, at least two, and maybe five minutes.
The tree of the handle of a knife or butt of a gun is always good to refresh from time to time with ballistol or oil. linseed, vegetable. An alternative to hot wax will be natural oils, latex-based formulations, silicone oil, special oils for wood (once sold in Ikea), varnishes.
Each option has its pros and cons. So, the disadvantage of wax is that it is undesirable for knives, the assembly of which used glue (it usually does not tolerate elevated temperatures).
Natural oils cure for a long time (forever). Ballistol with regular use gives a nice smooth surface.
Silicone oils do not polymerize, but are good in wood and are moisture resistant. Varnishes perform exclusively surface protection. After the wax cools down, I removed the excess from the handle, polished it on a felt circle, and then manually with a paper towel.
The last thing left is sharpening. It is impossible to leave the blade simply reduced to zero. it will crumble, and this is verified. You need to make a small approach.
I did it on Russian diamond bars (in the direction of decreasing grain size), after wetting and rubbing them with a bar of soap. Soapy water sticks to stones better and lubricates better.
I finished the fine-tuning without pressing the edge forward with soapy water on the Green brazilian slate. All! The knife shaves. Having taken a test birch log well dried in the workshop (it was 5-6 years old), I checked the sharpness and resistance of the cutting edge, convenience and controllability of the knife on it with dashing planing.
Bottom line: the knife tends to bury itself viciously into a tree, cuts vigorously, is comfortable in the hand, the cut of the tree glistens like polished, and the edge is intact and not glisten. In general, the knife can be safely given to work.
It is nice to see the children’s sparkle in the eyes of a healthy man looking at a new useful toy born with him!