Drills for confirmation

Confirmation is a furniture Euro screw that replaced the usual slotted screws, which were mass-produced in the USSR. Being a self-tapping screw, it is screwed only into pre-drilled holes. Trying to screw it, like an ordinary self-tapping screw, into an un-drilled chipboard or MDF, you will ruin the piece of furniture. Therefore, it is so important to choose the right drills for the confirmation.

The drill for the confirmation is selected for the specific diameter of the Euro screw, measured by the head and protrusions of the threaded groove. Euro screws are installed on furniture made of natural wood, VLA-boards and chipboard. The load on the screwdriver (hex wrench used as a torque tool) is very high.

In a building materials store where fasteners are sold, a drill for confirmation is checked for a Rockwell hardness indicator. It should be at least 61 - manufacturers tested over many years immediately indicate what this characteristic is. Not all drills for Euro screws indicate the hardness of the steel from which they are made. Russian drill suppliers indicate the grade of tool steel. Steel grades P9M5 and P18 are considered to be the leaders; abroad it is HSS-4341. Simply put, these designations indicate high speed (tool) steel.

The best, from the point of view of usability, are euro screws and holes in furniture parts for them, where the drill diameter for the euro screw was correctly selected. There is no thread in the parts of furniture ready for assembly, and a standard chamfer for the head of the confirmation is provided by the manufacturer. All these initial data allow you to quickly assemble a particular piece of furniture.

For one and the same technique, three actions are performed simultaneously. Confirmation drills are often sold in a set - the user (or furniture maker) will immediately choose the one he needs. To increase the efficiency of assembly, the drill can be brought to the desired state. The proprietary drill bit is sharpened at the most acute angle, which allows you to drill the board faster, to exclude the "walking" of the point at the beginning of work.

Confirmation drill is easier to drill holes in lumber slabs (laminated chipboard, LMDF, plywood, laminate). For it, the exact diameter of the hole may be critical, the correspondence of the drilling axis to the perpendicular lowered to the plane of the board at the drilling point. In Russia, only technical conditions apply to Euro screws - GOST was not issued for them. But suppliers of confirmations and drills for them use a ruler of sizes.

1. Asymmetrical screw thread for wood products. The step is slightly larger than on most similar self-tapping screws.
2. There is no sharp edge at one of the ends of the rod.
3. The head is slightly larger than that of simple self-tapping screws. It consists of cylindrical and truncated-conical parts. At the end of the truncated cone there is a hole for an internal hex key or Phillips recess for ordinary bits and screwdrivers.
4. The working part of the Euro screw is a smoothed rounded area that fits the headrest. This part puts the bolt in the center and allows you to securely connect the wooden parts to each other. The threaded area is screwed into the hole.
5. The thread is cut at an angle of 45 degrees - this feature gives the assembled structure additional rigidity.

Euro screws are made of steel 08, coated with zinc - GOST-1050 is responsible for this. Anodized aluminum is sometimes used. In a set with a piece of furniture, the manufacturer often includes a hex key or a curly bat. Furniture items are most often drilled by the manufacturer for drill holes 5x50, 6.3x50, 7x50 and / or 7x70.

The selection is made for a specific size and manufacturer. Drills from little-known Chinese firms are often found. Despite the significantly reduced cost, compared to the promoted brand, such a drill is far from the best quality. Chinese manufacturers often save on technologies for the production of extra-strong steel that would serve for a long time. The steel grade is 9XC at best, and U7 / 8 in ordinary ones.

Such steel is also a tool steel, users note its low quality, calling it "plasticine", which deteriorates when the load is adequate to the furniture assembly process. The drill dulls prematurely from overheating, the steel is "released" or initially does not have the declared hardness and stiffness. As a result, it is impossible to work further with a blunt instrument. The worker, finding that the drill does not go deeper with the required speed and efficiency, increases the pressure on the drill.

But the increased effort does not solve the problem, and the piece of furniture gets damaged instead of an even hole, in which the Euro screw will not hold securely enough. Russian manufacturers offer their solutions - products of the Tula Instrument Plant, the BSI-Instrument enterprise... American drills on the Russian market are represented by DeWalt, Swiss - by Archimedes.

The length of the seating zone of the drill corresponds to the length of the flattened part of the Euro screw. The countersink zone of the stop does not go beyond the 45-degree angle, and the transition to the screw (threaded) part should be extremely small. The graininess of the cutting edge is unacceptable - this will lead to overheating of the drill during long working hours, as well as to loosening of the steel and burning of the drilled holes.

The confirmation drill has a removable or non-removable form factor. The removable version gives more possibilities, it is like a combined solution - and the quality of the holes remains practically unchanged. The drill shank needs periodic tightening of the chuck, which is somewhat weakened during the drilling process, otherwise it will turn and drilling will slow down. Confirmation drills need an electric drive with high speeds - 5000-10000 rpm: the higher the angular drilling speed, the more precise and accurate the drilled holes are.

A clear and reliable fixing of furniture components is determined by adherence to the rules of use. They are as follows.

1. Before starting to work on wood, check if the drill parameters are comparable for the specific confirmation screws.
2. Mark the pieces of furniture for future holes - take into account all the indents.
3. The two parts to be fastened must be held in the desired position. This is possible thanks to clamps with a rubberized working coating - so as not to spoil the appearance of furniture components.
4. Do not deviate from the perpendicular position of the drill. Violation of the right angle relative to the plane of the part being drilled threatens the instability of the structure, breaking off of its parts, loosening of the assembled product. As an appropriate device, you can use a hand-held milling cutter, in which the crown is replaced by a drill, and the position on the coordinate axes is rigidly fixed using holders (brackets, clamps, additional clamps).

An additional convenience is a device that provides a high-quality additive of the fastened components. They are used for drilling test holes with a much smaller diameter. Using such a device means increasing the efficiency when assembling furniture - especially when the work is on stream, one or two masters must serve a dozen objects in a day or several hours. The accuracy and high quality of the confirmation holes are guaranteed.

Observing the rules for choosing a drill for confirmation, as well as recommendations for working with such drills, a specific customer (or furniture maker) can be sure of a high quality of assembly. Deviation from the above recommendations in the worst case turns into an urgent repair or replacement of a piece of furniture that has been damaged under normal load.