Concept
A miter saw is a tool designed to make straight cuts at a given angle. The saw cut angle can be either 90 degrees or 45. Its main advantage is that it copes well with long details and unusual shapes of surfaces. A striking example of these is a plastic floor plinth.
But this tool has other features as well.
The appearance of this unit resembles a conventional circular saw (circular) mounted on a movable arm. It allows the discs to descend not only vertically, but also at any angle of inclination. This tool can cut various materials:
- wood;
- metal (in particular aluminum);
- plastic;
- stone.
Views
Saw blades are divided into two types: carbide and monolithic. This division describes a difference that is immediately apparent. The fact is that on some discs the cutting part is soldered to the teeth, and some are simply a single product (monolith).
Monolithic
A distinctive feature of monolithic discs is the large number of teeth. Working with such a blade, it is much easier to get a clean cut. But it is worth noting the poor ability of these cutting wheels to keep sharpening and the need for periodic divorcing of the teeth.
Sharpening the metal is not difficult, but the large number of blades slows down the process.
Carbide
Carbide teeth are considered more reliable because they are stronger and do not require constant sharpening and patching. These scoring discs have the widest range of options and help you save time thanks to their reliability. However, a significant drawback is the large number of low-grade counterfeits, even of famous brands. In such a product, the soldered ends quickly fly off. After 5 minutes of cutting the cross-sections, only a few remaining blades can be seen on the disc.
But counterfeiting can also be successfully combated if you pay closer attention to the correct spelling of the brand, as well as the high quality and durability of the paint with which the marking is made.
Specifications
In total, there are two main indicators that you should pay attention to when buying
Diameter is a characteristic that affects the speed of rotation of the motor shaft. The size of circular saws is different, this also changes the parameters of the circle. The optimal ratio of size and speed can be presented in tables:
| Diameter mm. | Rotation frequency |
| 80 | 23 800 |
| 100 | 19 100 |
| 120 | 15 900 |
| 250 | 7 600 |
| 350 | 6 300 |
With an increase in diameter, the comfortable operating frequency always decreases
What to look for when buying a tool. On a circular saw with a permissible diameter of 100 mm, it will not be possible to install an eighty disc
Each disc is designed for a specific rpm allowed by the manufacturer. High revolutions are the main cause of metal burnout, after which it changes its shape and becomes soft.
To find out the baseline suitable for working with the snap-in, you need to read the information on the disk. The main characteristics of the brand will be written next to the brand label:
- Diameter;
- Working speed of rotation;
- Additional information (low noise level, anti-temperature coating materials).
Visual inspection of the web
For comparison, several discs will be shown that differ in appearance.
Selecting disks to check
Checking the flatness of the disc
The geometric flatness of the disc is checked with a metal ruler.To do this, a ruler is applied between the teeth from the side of the disc marking and the gaps are observed.
Checking the disc from the side of the marking
Then a ruler
applied from the back of the disc and also reveal gaps.
Checking the disc from the back
If the disc is flat, then
the metal ruler fits snugly on the canvas and there will be no gaps.
Teeth inspection
The teeth of the disc are carbide-tipped
soldered. The geometry of the teeth must be correct. A low-quality disc has teeth
go out of order and have different angles of inclination. This can be seen with careful
examining each tooth.
Inspection of the condition of the teeth
Inspection of the drinks
High temperature
the cutting plates are soldered to the disc. Solders come in different geometric
shapes: beveled, straight, conical, trapezoidal. All soldering on the disk
must be of the same size and of the same geometric shape.
Inspection of the drinks
If you compare the two
disc: expensive branded and cheap Chinese, then the branded disc has a size
more tricks. Such a disc is designed for 10-12 sharpenings, and a disc with small
it is impossible to sharpen more than 5 times by soldering.
Comparison of disc soldering
The quality of the cuts of the selected
disks are the same. However, it is better to have a disc with large soldering
withstands heavy loads and repeated sharpening.
Checking the thickness of the blade
Steel blade blade
it can be thin or thick. It is made by laser cutting. To reduce
Noise and vibration compensation slots are made on the disc blade. Quality
disks are provided with undulating expansion.
If the thin disc bends
under the pressure of the hands, the thick disc cannot be bent.
Checking the canvas under
hand pressure.
Thick discs
used when you need to make an even cut with a powerful saw. For rechargeable
circular saws buy thinner and cheaper blades.
Checking the angles of sharpening of teeth
The teeth have many angles
but the main one is the front angle of inclination. It can be positive or
negative.
Sharpening angles of teeth
From the front corner of the disc
disk capabilities depend:
- longitudinal cut - 15‒25 degrees;
- cross cut - 5‒10 degrees;
- universal application - 15 degrees.
Laminated
surfaces, plastic and aluminum are sawn with discs with a negative angle. The wood is sawn with discs with a positive angle
sharpening.
Positive angle disc
Longitudinal sawing
perform with discs with a positive sharpening angle and a small amount
teeth. If the sharpening angle is 18‒25 degrees, then sawing will take place quickly, but with
low quality.
Rip saw blade
Typically cuts
wood along and across is produced by a universal version of the saw blade,
for example, with a sharpening angle of 15 degrees.
Universal disc
Selection by number of teeth
Saw blades distinguish
by the number of teeth. It is believed that if the teeth are from 10 to 40, then this is a small
number of teeth. 40 to 80 is the average tooth size and 80 to 90 is
this is a large number of teeth.
Rough cut
is obtained by a disc with 16 - 24 teeth.
Disc with 16 teeth.
When you need a smooth
cut, then choose a disc of 36-48 teeth.
48 teeth disc
Assessment of the sharpness of the teeth
Experienced users
always check the condition of the teeth. A disc with blunt teeth does not cut well,
heats up, saw marks remain on the wood.
Verification is carried out
fingers. When the disc is sharp, the teeth catch the skin and feel light
tingling. A blunt disc has smooth teeth.
Finger Checking the Disc
Evaluation of web coverage
So that the disk does not
wood resins adhered, and it did not get stuck in the cut, the blade has a smooth
mirror coating. There should be no scratches on it.
Disc cover
Output
There are no universal discs. The choice of each disc must be approached carefully.Sometimes an expensive but high-quality saw blade is more profitable to buy than a cheaper and short-lived model.
Based on the materials of the master class from the "Aquila Workshop" carpentry workshop, processed by Viktor Prokhorov
Category: Machine tools
Go to groups and Odnoklassniki
Outside diameter
This selection parameter is in direct proportion to the dimensions of the saw cover itself. If you take a disc with a large diameter, then it will not be possible to install it on a tool with a small diameter casing. Operating with discs that are too small is also fraught with consequences.
The outer dimension does not affect the cutting speed, but it determines the cutting depth. In hand tools, cutting components with a diameter of 130-250 mm are used.
With a large immersion of the blade into the surface of the material, the load on the engine increases. It is recommended that the teeth do not protrude more than 10-20 mm above the working plane.
Influence of tooth shape on cutting
Significant the quality of the cut is influenced by the shape of the teeth.
- With a flat top. The saw blade for wood with this tooth shape is well suited for cutting hard wood. It pulls out tough fibers, allowing efficient sawing motion. Best suited for ash, oak, beech, birch. The tooth is symmetrical, without setting.
- With pronounced wiring. Designed for strong gnawing into wood. Provides high performance with dirty cuts. The places of processing must be additionally sanded with sandpaper.
- Triple shavings. Such a saw blade for wood is designed according to a specific system that combines the two previous technologies. First comes the set tooth, which cuts out large blocks of wood. The next prong cuts off the tracks from the previous one. This creates a high cutting performance, but the cut itself is clean and free of sticking out fibers.
- Fine. The most common finishing disc technology is four teeth with negative tilt and set and one for undercutting. This technology even allows for finishing cutting. Suitable for cutting chipboard and MDF in the manufacture of furniture.
Types of discs
There are no universal discs on the market that can handle all kinds of materials. The main difference is the shape of the cutting edge. Even for one type of raw material, like wood, there are several circles on the market that are designed for hard and soft woods. Some are designed to work with soft wood (pine, fir, spruce) and hard wood (ash, beech, cherry).
The indicator of durability is the presence of victorious or diamond tints on the teeth. These are small pieces of carbide minerals (tungsten carbite) that are significantly harder than metal and wood.
Metal monolithic models are manufactured carbon steel... The cutting edges are thermally hardened, which increases their density and hardness. Thanks to this, they do not dull longer and remain suitable for normal operation. If the edge is dull, it can be sharpened with stones or special emery machines. Much cheaper in comparison with the victorious ones. The metal used for manufacturing must not be overheated. As the temperature rises, tempering of the steel may occur. From this, the metal will become soft, practically inoperative.
Brazed models offer better performance as the linings are significantly harder than conventional metal. They do not require additional sharpening, which is why they can last longer. But cannot be repaired if damaged. Diamond will win and is afraid of overheating.
If the soldering has worn out, they can be sharpened. This requires an engraver with a diamond disc and additional polishing with a vulcanite wheel or felt with GOI paste.
Saw blade marking
To the choice of the disk always
proceed after studying the marking.
Disc blade
be sure to mark.In order for the marking to persist for a long time,
high-quality disks make it with a laser. Long-term paint
erased, and information from the marking is needed not only during the purchase of the disc, but
and with its repeated use.
Saw blade marking
Thanks to the marking
the user will find out:
1. Manufacturer's brand and logo
To famous brands
include discs of brands: Bosch, Hammer, Makita,
"Bison", "Attack" and others. These are high quality discs. At the same time on the market
there are many medium quality discs that are made in China.
2. Purpose of the disk
Circular saw
sawing different materials. This is not only wood, but also laminate, rubber,
aluminum, chipboard.
3. External disk size
Size is limited
under the saw guard. This parameter determines the cutting depth.
Hand saws work with 130-250 mm discs.
4. Bore size
The cutting blade must
fit well on the shaft. This is a prerequisite for safe work. Disks
produced with bore holes from 16 to 32 mm.
5. Cutting width
From the thickness of the canvas
the cut depends. The thin blade makes a narrow cut, but the blade is short-lived. At the disk
with a thick blade, a wide and sloppy cut. For hand tools
select a 3.2 mm disc.
6. Number of teeth
On saw blades
the number of incisors is different. This is necessary for working with different materials and
performing different cuts. It is considered optimal to have 5 or more
discs with a different number of teeth.
7. Rotation speed
Parameter depending on
the possibilities of the circular saw and the diameter of the blade. It is determined by the number
rpm. At high blade speeds, the cut is more
high quality.
8. Direction of rotation
As indicated by the arrow
the material is cut. In the opposite direction, not only will there be
cut, but safe work with the cutting tool will not be ensured.
For the final
the choice of the saw blade, proceed to inspections and checks.
Circle replacement
When performing repairs even at home, the periodic change of materials also requires the replacement of the saw blade. It is not difficult to change it, but it is still worth knowing the correct sequence of actions for your own safety.
It is necessary to start by installing the protective plastic casing (if any) in the upper position. To do this, unscrew the side auxiliary bolt, raise the structure, and then fix it with the same bolt, just in a different position.
Next, take a hexagon, which unscrews the clamping bolt in the center. In this case, on the back of the saw, it is necessary to press the button of the shaft locking mechanism, which is a stopper. It prevents the shaft from moving. Therefore, while holding it, you can press out the central bolt using the hexagon. Then the bolt must be unscrewed (you can use your hands), remove the side stopper (looks like a wide washer) and then the disc.
Installation is carried out upside-down. The disc is put on the shaft, then a lock washer is placed, then the bolt is screwed in by hand until it stops. To clamp the nozzle, you must press the button, and, while holding it, tighten the central bolt to the limit using the hexagon.
For information on how to sharpen a miter saw blade, see the video below.