How to Sharpen a Trimmer Disc

How to Sharpen a Trimmer Disc

A trimmer is a fairly common garden tool purchased for mowing grass. Models with fishing line are suitable for soft grass, but if you need to deal with coarse shoots and shrubs, you can not do without a disk trimmer.

Benefits of Disk Trimmers

When you have to mow tall grass, it often gets tangled up on the fishing line and the trimmer spool, because of which you have to stop work and remove these tangles of grass with your hands. In addition, over time, the trimmer coil from this can break. As for the cutting disc. it can easily cope with tall grass.

The drive is also more efficient when you need to mow dry grass, burdocks, cowberry, shrubs and shoots. The only thing the knife is afraid of is stones. For haymaking, the trimmer disc is the ideal solution.

over, metal discs do not wear out, so they do not need to be changed, unlike fishing line, which eventually becomes unusable.

Varieties of discs for trimmer

The disc for the trimmer can be made of different materials. And in order to decide which disk for the trimmer is better. metal or plastic, you need to decide what you will mow. So, a plastic disc is designed for low and sparse grass, while a metal disc can easily cope with very thick and tall grass, shrubs, dry grass.

The shape of the disk mill for the trimmer can be with 2, 3 or 4 cutting edges. Typically, these components are included in the basic set of low and medium power tools. You can fight them with dense grass and small bushes.

Saw blades are installed on powerful and professional equipment, which have up to 80 teeth, and sometimes also carbide (win-win) soldering on the teeth. Such a winning disc for the trimmer is rarely used in private households, mainly it is placed on professional lawn mowers. It has a very long resource and universality of application for both fresh grass and dry impassable weeds.

Discs also differ in blade thickness, which can range from 1.3 to 4 mm. Thin discs cut grass cleanly, quickly, and accurately, but they get dull faster. The thickest knives do not wear out for a rather long time, but are more suitable for rough shoots and weeds.

As practice shows, the most common form of a knife for a trimmer is round with teeth along the circumference. A frequent choice is also its variety with 4 large teeth and a number of small teeth between them. They most effectively help in cleaning the site, are easily installed on any model of trimmers.

Installing a disc on a trimmer and observing safety measures

After you have decided which disk to take for the trimmer, you need to learn how to install it correctly. Initially, make sure that the mounting hole on the disk has the desired hole, otherwise the disk simply will not fit your trimmer. And if you manage to fix it on the instrument, during operation the disk may come off and seriously injure you.

Typically, each manufacturer for each model of manufactured equipment also produces the appropriate equipment, so the choice of a knife does not have to become something very complicated. When you have installed the drive, check how securely it is attached.

If the disc is metal, it can only be installed on a trimmer with a flat bar, because this is due to the design features of the unit. When mowing grass, bushes and thin trees, the disk, bumping into an obstacle (such as a stone), bounces back, that is, in your direction. And when the bar is straight, the distance from the head to the legs is sufficient for your safety.

Sometimes, some novice car owners are faced with the need to replace the drive. one or more, and this task is in fact more difficult than it looks from the outside. And no wonder: 4108, 6J, ET47, Dia 63.3, R15. what is all this ?! Let’s figure it out together.

Correctly select the wheels on your existing car, along the way, having figured out all the necessary parameters.

Regardless of which car you have, when choosing new drives you need to consider the following options:

  • type of disk;
  • mounting (or landing) diameter;
  • the number and diameter of the mounting holes (PCD);
  • disk width;
  • disk outreach (ET);
  • diameter of the central (hub) hole;
  • shape of mounting holes;
  • the presence of humps.

All discs by type of manufacture are generally divided into three types: stamped, cast and forged. The question of choosing a specific type is a topic for a separate material, but here we will present the main differences.

Stamped wheels. the cheapest: these are the very wheels that you see on the basic trim levels of budget cars, and they are usually covered with plastic decorative caps. They are made of steel and painted with enamel. Among their advantages, in addition to the lowest price. high maintainability. The fact is that stamped discs do not break upon impact, but crease, and subsequently they can be easily repaired. The main disadvantage of such wheels is their high weight and lack of design: this is a purely functional product.

Alloy wheels compete with stamped in popularity. Such discs are not made of steel, but of a lighter alloy. usually aluminum. Thanks to the manufacturing technology, alloy wheels can have the most diverse form, which, combined with less weight than the “dies”, provides them with popularity. Among the shortcomings of such wheels, one can mention a higher price and lower maintainability: alloy wheels do not crease during a strong impact, but crack. Of course, the technology of welding repair and rolling has long been mastered, but it is impossible to guarantee the preservation of the original properties after repair.

Video: How to Sharpen a Trimmer Disc


Forged wheels. The most high-quality and expensive option. They are made by hot die forging, which provides the best internal structure of the metal and, consequently, the highest strength with the least weight. The reverse side of this method is the low prevalence of products and the high price.

In addition to the above three types, there are also the so-called prefabricated disks. but this is already exotic, and we will not touch them. In general, for the average car owner, the choice is between inexpensive, but boring stamped and more expensive and beautiful alloy wheels.

This is an obvious parameter: the diameter of the disk circumference in inches. As a rule, it is denoted by the letter R: that is, the disk R 17 has a diameter of 17 inches.

We note specifically: the letter R itself does not refer to the diameter and came from the tire parameters, where it is also mistakenly used in the value "radius", in reality, implying the diameter of the tire. In the case of the R bus, this is a marking of the radial construction of the cord, for the disk, this marking is actually not relevant. However erroneous "radius" in meaning "diameter" and the accompanying R are so accustomed to it that most sellers and disk selection services are already used by default.

Permissible rim diameters for your vehicle are indicated in the instruction manuals and on the stickers in the doorways. together with the recommended tire pressure. When buying tires, it is worth remembering that their landing diameter should match the diameter of the wheels.

It is not recommended to exceed the maximum diameter specified by the manufacturer: disks that are too large, in addition to potential geometric incompatibilities, change the parameters of the suspension, affecting the wear of the chassis. In addition, the larger the drive and the lower the rubber profile, the less comfort bodes on poor roads. However, changes in diameter within the limits specified in the manual, and even an inch over, as a rule, pass without significant consequences.

This is the so-called “bolt pattern”: the number of holes and the diameter of the circle on which they are located (by the way, the English PCD is just the diameter of the circle, “Pitch Circle Diameter”). The number of mounting bolts can be different and increases with increasing weight and speed of the car: usually 4-6, but it can be more and less (minimum 3). Most VAZ cars have a 4×98 bolt pattern, with the exception of the Oka (3×98) and Niva (5×139.7), as well as new models like Largus (4×100).

The drive pattern must be observed: although some discs — for example, 4×98 and 4×100 — seem interchangeable, this is not the case. The seemingly insignificant 2 millimeters difference in diameter of the circle on which the mounting holes lie will greatly affect the installation: only one of the four fasteners will be properly tightened, and the rest will be offset from the center, causing the wheel to run out. Part of the problem can be solved by using bolts with a “floating cone” (about them a bit later), but in general, the use of discs with inappropriate bolt settings should be avoided.

This option is as simple as diameter: this is the width of the disk in inches. Usually in the parameter list it is indicated by the letter J: for example, 5.5 J is a five-and-a-half-inch-wide disk.

The width of the disk, as a rule, is indicated in the same places as the permissible bore diameter, along with it. In addition to the geometrical parameters for the car, the width of the disk is important when choosing tires: the tire is designed to use a certain width with the disk, but with some margin of error.

The ejection of the disk is the distance from the attachment plane of the disk to the hub to the longitudinal axis of symmetry of the disk. Let’s just say: the central axis of symmetry is a fishing line that divides the disk in half according to the width described above, and the mating plane is the point where the disk contacts the hub and is screwed to it.

Departure can be positive, zero and negative: if the axis of symmetry is closer to the car than the attachment plane, then the departure is positive, if they are on the same axis, then the departure is zero, and if the axis of symmetry is more distant from the vehicle than the attachment plane, then it is positive. In other words, the larger the outreach, the deeper the disc sits in the wheel arch, and the smaller it is, the more the disc protrudes outward.

Departure is a rather important parameter: it also directly affects the operation of the suspension and wheel bearings. Improper reach not only increases or decreases the track, but can also cause accelerated wear on the undercarriage and bearings.

The diameter of the central hole is a parameter that does not need additional explanation. It is usually referred to as “Dia,” “DIA,” or “D,” in the list of disc characteristics. This is also an extremely important indicator: if the central hole of the disk is smaller than the required one, the disk simply cannot be installed, and if it is larger, then centering rings are required to center the disk on the hub.

Many people mistakenly believe that when installing a disk with a too large central hole, it itself is centered on the hub by tightening the bolts, but this is not so. Accordingly, the beating and vibration that does not disappear after balancing the wheels is an occasion to check the coincidence of the diameters of the central hole of the disk and the hub and the presence of centering rings if necessary.

The shape of the mounting holes is important in terms of the type of bolts or nuts that the disk will be attached to. As a rule, bolts and nuts for stamped discs have only a slightly conical shape of the plane adjacent to the disc when tightening, and the bolts are also noticeably shorter.

The latter is due to the minimum thickness of the stamped disc. The cast disc is noticeably thicker than the stamped one, and in addition, its mounting hole has a more pronounced conical shape, which requires the use of other fasteners. In addition to the cone, the mounting location of the mounting holes of some discs can be designed for the use of fasteners with a hemispherical and flat working part.

And one more thing: there are bolts with the so-called “floating cone”: they allow you to partially compensate for the slight discrepancy between the PCD disk and the required parameters. The working conical part of such bolts is made in the form of a separate ring worn on the bolt, and moves relative to the longitudinal axis of the bolt when tightened.

Humps. These are the protrusions on the outer surface of the disk that fix the tubeless tire to the disk. Remember the pops that sound when the tire is inflated after mounting on a tire? This is the moment of “landing” of the tire: the side ring of the tire sits between the hop and the edge of the disk. In fact, this indicator is the last one indicated in our material, because at present it is practically not relevant: almost all modern wheels are designed for installing tubeless tires and have humps.

However, if, for example, you decide to purchase retro disks of a respectable age, keep in mind that they can very well be designed to install exclusively chamber tires without humps. However, tubeless rubber can be installed on them, however, the issue of its tight fit, as well as safety when driving will remain open: with insufficient pressure in the tire, the risk of “taking off” in the corner will be very high.