How to choose a drill for metal

Work instructions

Using the correct tool is not a guarantee that the hole will be straight and smooth. It is also necessary to follow the elementary drilling rules so as not to melt the edges, not to get deep burrs, from which cracks subsequently appear.

Drilling techniques

Conventionally, two drilling techniques can be divided:

• for holes with a diameter less than 5 mm;
• for holes with a diameter greater than 5 mm.

Small holes are drilled at minimum speed, gradually increasing them up to 1000. The best option is to adjust the speed of rotation from 500 to 1000 using reverse (respectively, it is better to use drills that support this function). In this case, you should not drill for more than 10-15 seconds in one approach, making a subsequent break for at least 10-20 seconds. This will prevent overheating from melting the edges of the hole. It should be noted that an increase in temperature above 120–150 ° C will also lead to darkening of the sheet material.

The radius of the hole in the plexiglass should be gradually increased, otherwise it may crack

For drilling holes with a diameter of more than 5 mm, it is recommended to start with small diameter drills, gradually increasing them in increments of 2-3 mm. This will prevent overheating and will also allow drilling without pressure on the plexiglass itself. In addition, water cooling can be used, that is, water is supplied to the drilling head through a dropper or syringe (in many machines, such a cooling system is provided initially).

It is also important to perform drilling on an absolutely flat and smooth surface. Wood is ideal for this - it is inferior in hardness to plexiglass, so it will not be able to scratch it

It is better to take plywood or several layers of fiberboard, chipboard.

Step-by-step instruction

In most cases, the drilling process is carried out as follows:

1. Prepare the surface on which the plexiglass sheet will be located. It is optimal to use plywood, wooden board, pallet for this.
2. Arrange the plexiglass sheet. It is recommended that the place where drilling is not carried out be covered with geotextile or any other fabric, which will protect the material from the ingress of polymer and metal sawdust, which could theoretically scratch it.
3. Install a compatible drill bit in the drill, select low speed, drilling mode (no impact).
4. Start drilling at low speeds. After the appearance of a minimum depression, increase the speed to medium and in this mode drill to ⅔ of the material thickness. Then raise the speed to maximum, periodically reducing it to a minimum to avoid overheating.

In the event that the edges of the hole are melted, it is recommended to use a drill of a slightly larger diameter, but already preventing overheating of the plexiglass. When burrs appear, you can get rid of them with the help of a mineral stone drill (used mainly in drills for drilling). Naturally, the minimum revolutions are maintained.

Drill drivers are not suitable for drilling plexiglass due to low speed

In total, in most cases, you can drill plexiglass using an ordinary household drill. Screwdrivers / drills will not work due to the low number of revolutions (if you use them, burrs form, and you also have to apply a lot of pressure).

The main thing is to choose the right drill, taking into account the thickness of the material and the diameter of the required hole, and also to prevent it from overheating while drilling the plexiglass. To obtain large holes (over 10 mm with a thickness of more than 7 mm), it is recommended to use stationary machines with a water cooling system for the drill.

Terms of use

It is also necessary to drill the glass correctly. In most cases, work is carried out on the surface of display cases, window, furniture products. In some cases, a special machine is used, but usually a hand tool is sufficient.

It is important to be careful when drilling, as the glass surface will crack and shatter easily if handled incorrectly. The process of forming holes in glass is divided into 2 main stages.

Surface preparation

Before starting drilling, you need to carry out certain preparatory work.

Degrease the surface. You can take alcohol or turpentine, then thoroughly wipe the glass dry.

Securely fix

It is important that the glass does not move. You can use special clamps with soft suction cups.

Provide a secure footing

The surface area needs to be larger than the size of the glass sheet.

Mark drilling point. To prevent the tool from slipping, it is worth sticking a small square of plaster or tape in this place. Then mark with a marker.

Carrying out works

After all the preparatory work is completed, you can start drilling. A suitable drill fits into the tool holder. It is installed strictly perpendicular to the glass surface. Drilling is not performed in one go. The depth is increased gradually, allowing the drill to cool down - it will heat up intensively during rotation. Having immersed the drill almost to the entire thickness of the glass, it is necessary to stop 1-2 mm from its surface. After that, the sheet is carefully turned over. Continue drilling from the reverse side. This minimizes the formation of cracks, significantly reduces the risk of chipping along the edges of the hole.

To obtain the most even edge, additional processing with fine-grain emery paper is used.

When creating holes in glass, it is very important to correctly position the drill. Do not push hard on the tool, push

Every 5-10 seconds of operation, it is recommended to cool the heated drill in a specially prepared vessel with water.

For information on how to drill a hole in glass without a special drill, see the next video.

What woodworking tools look like and how they differ from metal drills for a drill

In appearance, twist drills for metal drills can be easily recognized and distinguished from analogues for woodworking. The instruments of the second category are of two types.

Standard twist (twist) drills for wood

Standard twist drills for wood look like this.

Photo # 2: twist drills for wood

1. Woodworking tools have special lances at the ends. They make centering much easier and make the machining process more precise.

2. Wood and metal drills can be distinguished by the angle between cutting edges. For instruments of the first type, it varies from 90 to 100 °. The angle between the cutting edges for metal drills is 110–140 °.

3. Woodworking tools may have special cutters.

Picture No. 3 construction of standard twist drills for woodworking

Lewis twist drills

Lewis twist drills look like this.

Photo # 3: Lewis Twist Drills

They are designed for drilling perfectly smooth deep holes of small and large diameters in wood. By design, they visually differ significantly from standard ones.

Image # 2: Lewis twist drill design

The main elements of such drills are the central core and the massive Lewis spiral encircling it. It is also called auger. To facilitate centering, these drills have special threaded tips. Another difference between tools in this category is the small angle of inclination of the groove.

Peculiarities

Conventional drill bits are not suitable for working with brittle materials.Here it is recommended to use their specialized options, so as not to damage the surface, to avoid the appearance of cracks and chips. The glass drill must be harder than the material itself. This requirement is met by products with diamond or vicite plating. The material for the manufacture can be different. Usually it is tool steel or brass

The type of tip is the most important, in addition to the hardness of the alloy. It can be in the form of a feather or a spear.

Such options are relevant for drilling small holes - no more than 12 mm in diameter.

The cleanliness and quality of the hole formation will greatly depend on the skill of the specialist, but small chips along the edges are not considered a serious marriage. Diamond spraying makes it easier to drill through glass surfaces. The drill's stroke turns out to be much softer. When forming large-diameter holes - for example, for assembling furniture, other drills are used, with a tubular tip or crown.

Basic tables for drilling metals required for the correct selection of cutting data and other needs

For drilling metals, craftsmen most often use the following basic tables.

Table 1: selection of cutting conditions when drilling metals

Table 2: correction factors

Table 4: Selection of Drilling Speed ​​in Complex Austenitic Steel