WHAT ARE HAMMER DRILLS USED FOR?
What are hammer drills used for?
Impact drills are used to make holes in mineral building materials: concrete, brick and stone.?For their drive, depending on the type of these tools, impact drills, drills and screwdrivers as well as SDS-plus or SDS-max electropneumatic hammers are used.
Contents
How does a hammer drill work?
It performs two interconnected movements:
The first of the movements is only for the application of impacts (impacts), resulting in crushing of the workpiece.?It is a basic movement that allows the processing of building mineral materials (concrete, granite, etc.).?As is known, they have a very compact and slightly flexible crystal-lump structure, which is difficult to machine.?Therefore, they can be effectively treated either by impact (crushing) or by grinding with a suitable tool of high hardness (e.g. cut with a diamond disc).
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Good to know:
For the effectiveness of impact drilling, the most important is the amount of impact energy applied with a drill.?The higher it is, the faster we can drill in hard building materials.
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As mentioned, the second type of movement that a hammer drill performs is a rotary movement.?This is a complementary movement, albeit necessary, because without it drilling is impossible.?It causes the rotation of the blades of the drill in the drilling axis, which gives the hole a cylindrical shape.?This movement is also used to drive the helical grooves of the drill, which transport the material from the inside of the hole to the outside.?This is necessary so that the accumulated spoil does not stop the drilling process.
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Types of impact drills
Many types of hammer drills have been developed.?Their construction is very similar, although optimized to the size of the impact energy transmitted by them.
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And so, for the application of low-energy and high-frequency impacts, impact drills with cylindrical shanks?used in impact drills and drill-drivers?are adapted.?On the other hand, drill bits with SDS-plus and SDS-max holders?used in hammer drills and combi hammers?are designed to transmit much higher impact energy.
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Drill diameters:
Spiral Drills:
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We will make holes with a diameter of 40 to 80 mm with punch drills, and?with crowns?- from 40 to 155 mm.
In addition to them, we have?SDS-max (spiral and lace)?piercing drill bits and SDS-plus and SDS-max impact?crowns.
Drill bit with SDS-max shank, diameter 55 mm, for drilling holes for conduits and pipes.?Recommended especially for installers.
领英推荐
Impact crown with a diameter of 65 mm equipped with 8 cutting inserts made of high-quality sintered carbides.
Crown with a diameter of 68 mm made of carbon steel resistant to deformation under the influence of high temperature.
Hammer drill types
Impact drill bits with cylindrical shank
They consist of a two-blade widia, a two-thread spiral, a neck and a cylindrical handle.?Widia is properly sharpened and fixed in the steel drill head using industrial brazing technology.?Thanks to this, their connection is both highly mechanically and thermally resistant.?The bodies of the drill bits in question are made of chrome-molybdenum steel?, which enables effective transfer of rotation and impact energy and ensures a long service life of the tools.
In these drills, as already mentioned, we have a cylindrical shank for their installation in the impact chucks of drills and drill-drivers.?These tools are available in diameters of 3 - 30 mm and overall lengths of 50 - 600 mm.
They are designed for drilling in bricks, masonry and not very hard concrete, e.g.?Yato series of drills from YT-4361 to YT-4385.
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SDS-plus and SDS-max impact drill bits
Good to know!
SDS-plus and SDS-max drill bits are used for drilling in concrete, reinforced concrete, granite and similar materials, for drilling holes with diameters from 4 to 32 mm and depths from 110 to 1000 mm (SDS-plus) and 12- 52 mm and depth up to 1200 m (SDS-max).
These drills have two (properly profiled monolithic straight edge), three (in a star arrangement) or four (monolithic in a cross arrangement) blades, made of sintered carbides with a clearly distinguished centering tip.?They are deeply embedded in the steel head and connected to it with industrial solder, which is characterized by high mechanical and thermal resistance.
A slightly different design of the blades have SDS-max drill bits designed for drilling in stone.?For these tools, the two blades have been replaced with carbide pins.?They therefore have 2 edge blades and two pin blades.?The blades are made of appropriate grades of sintered carbides, very hard and with a coarse-grained structure, which are highly resistant to abrasion and chipping.
As mentioned, the widium edges of the blades form a pointed tip to center the hole axis and allow accurate point drilling.?So we can say that the SDS-plus and SDS-max impact drill bits are dynamically shaped like a sharp tip.?Thanks to this,?they enable very effective impact work and fast drilling in hard building materials.
A very important element of each SDS-plus and SDS-max drill is its monolithic steel body.?It distinguishes:
In these tools, depending on the version, 2+2-flute or 2-flute spiral grooves are used.?The core of the body is used to transmit impact energy to the drill head and dampen vibrations.?It must have adequate elasticity so that there is no excessive dissipation of impact energy and reduction of drilling speed.?It is known that the dissipation of impact energy increases with the length of the drill bit.?Therefore,?drills with a longer working part drill less efficiently.
Good to know!
SDS-plus and SDS-max drill bits should not only be selected based primarily on the diameter of the holes to be made.?Equally important is the criterion of their depth, because taking it into account allows you to achieve maximum work efficiency, which is very important in commercial conditions.
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