Router

A router is a power tool for cutting machining of wood and other materials that normally, in contrast to the moulder is set from the top to the workpiece.

construction

A router consists of a mostly gearless electric motor with a speed of 8,000 to 30,000 revolutions per minute, a collet for clamping the milling tool and a two-pillar-guided milling basket with a stroke between 35 and 80 mm. The guide pillars are attached to a stable base plate. The base plate can be provided with a sliding coating or an exchangeable plastic sliding surface. Stops and guides of various types can be installed on this base plate, so that, for example, circles or segments of a circle can be milled with a curved stop.

A distinction can be made between two basic designs for routers : In the meantime, devices with a 43 mm Euro neck and clamped separable into the milling cage are rarely found on the market (e.g. Metabo OFE 738). The motor and collet can then also be used separately as a straight grinder or built into a milling drill stand or CNC device. In most of today's designs, the milling basket is permanently attached to the motor. There are also machines in which only the motor (with connection cable) is pushed into a milling cage. In contrast to the Eurohals machines, the switch is located on the handles on the milling basket. The electrical connection is made via sliding contacts on the milling basket or the motor (e.g. Bosch Professional GOF 1600 CE).

The clamping range of the individual collets is usually between 6 and 12.7 mm. Usual dimensions are 6, 8 and 12 mm, more rarely are 4 and 10 mm. In machines in the Anglo-American system of units get ¹ / ₄ "(6.35 mm), ³ / ₈ " (9.53 mm) and ¹ / ₂ "(12.7 mm) are used. ¹ ⁄ ₃₂ ″ (0.8 mm), ¹ ⁄ ₁₆ ″ (1.6 mm), ³ ⁄ ₃₂ ″ (2.4 mm) are also available for use in small tools, such as those made by the Dremel brand , with a router attachment mm) and ¹ ⁄ ₈ ″ (3.2 mm) possible. Collet diameters up to 6 mm are mainly used for smaller milling cutters . For larger milling cutters and large infeeds, stronger machines are used, which are equipped with 8 or 12 mm collets. As a rule, various collets are included with a high-quality router.

The following basic shapes can be distinguished in terms of the shape of the handles:

The double knob is the classic shape with round handles on both sides for two-hand operation.
The pistol grip allows one-handed operation and has a knob on the opposite side.
The double handle is ergonomically adapted to the shape of the hand and is intended for two-handed operation. It is more comfortable in the main working direction, but more cumbersome than other handles from other working directions.

There are also stationary routers, which today are mostly integrated into so-called machining centers as CNC routers or designed as portal routers. Before the numerically controlled machine tools found their way into production, so-called copy milling machines (i.e. routers that are prepared for the exact reproduction of patterns) were common in furniture construction. A more recent development (as of 2018) are hand-operated CNC routers. Here the user roughly travels the shape with the machine and an internal position control corrects the corresponding offset. However, it is necessary that the contour is available as a CAD model.

use

Router with flush milling with ball bearing. The craftsman pulls the machine in this picture.

The router is suitable for the milling of slots , for bevelling and profiling , for stencil milling and freehand milling (. For example ornaments, patterns, fonts).

With freehand milling, the router is placed on the workpiece from above and guided over the surface by hand.

In addition, some models offer the option of installing them upside down in a table with a round opening for the milling tool . This offers advantages when e.g. B. very small workpieces are to be processed. For larger cutter diameters (from approx. 30 mm, e.g. flattening cutters), this procedure is preferable to the hand-operated one due to safety aspects. For this purpose, machines of the upper performance class are generally chosen, since the resulting high weight and thus the unwieldiness is not relevant, but rather an advantage (higher rigidity of the guides and smoother running).

Routers for the DIY sector are available with motor outputs from 450 W. In the professional sector, the small routers are between 900 and 1200 W and 2.5 to 3.5 kg. More powerful hand routers have an output of 1200 to 1600 W, resulting in a weight of 4 to 5 kg. The most powerful hand routers have an output of up to 2600 W (e.g. Mafell LO 65 Ec), but also weigh between 6 and 8 kg. While the small milling machines can score points due to their handiness, especially in the areas of freehand and template milling, where work is carried out with relatively small milling cutter diameters, the most powerful models with their weight are when machining with large milling cutters, especially in hardwood or in stationary operation (i.e. as a table milling machine) an advantage. Today's machines usually offer electronic speed adjustment throughout, so that the cutting speed can be adapted to the respective application. Constant electronics is also standard in higher-quality devices, which keeps the speed constant even under load and adjusts it if necessary, as long as the motor power allows it.

Application tools

Carnies - (above) and tooth cutter (below)

End mills serve as tools, some with soldered or screwed-on, and thus exchangeable, hard metal cutting edges. With ball-bearing support rings, which are located above or below the cutting edge, it is possible, for example, to mill a glued-on veneer edge flush without using a stop. The stop ring prevents the milling cutter from penetrating deeper into the workpiece than is flush with the surface of the board. Inexpensive milling cutters are sometimes also provided with simple run-on journals, which, however, can lead to burns on the run-on surface of the workpiece if they stay too long at one point or if the feed is too low. The advantage of the thrust ball bearing compared to the thrust journal is that it can be exchanged for a smaller or larger one in order to provide new possibilities with one and the same milling cutter. With a round cutter, the shape Round Over and Beading can be created.

Cutter types

Different profiles of a router

Different milling cutters are used for different requirements. The individual tools are dimensioned using a subset of the following abbreviations:

Cutting edge diameter (D)
Cutting length without shank (B)
Total length including shaft (L)
Shaft diameter (S)
Radius (R)
Number of teeth (Z)

It should be noted here that different manufacturers often use different letters, which can lead to confusion without a legend. The company Sistemi Klein uses the letters B and L for cutting edge length and shank, whereas Bosch uses L and G for the same information.

Groove cutter

Groove cutters are used to make square grooves and recesses. Dimensioning: D, B, L, Z, S

There are different forms of router bits. The standard groove milling cutter has carbide cutting edges that are soldered onto the side or additionally on the face. The best milling pattern, however, is obtained with the spiral groove cutter .

Flute milling cutter

The fillet cutter creates grooves with a semicircular cross-section or fillets on edges. Dimensioning: D, B, L, R, S. The letter R stands for the radius of the hemispherical cutting edge.

Rounding cutter

Rounding cutters are used for rounding edges. Dimensioning: D, B, L, R, S. The abbreviation R stands for the radius of the milled rounding.

Flush milling cutter

Trimming cutters are used to adjust glued, protruding materials. A stop ring above or below the cutting edges is used for this. Dimensioning: D, B, L, Z, S

Often they are also offered with a cutting point. These are used to be able to dip directly into the wood when exact copies of a workpiece with e.g. B. a pantograph .

Rebate cutter

Rebate cutters are used to mill rebates (rectangular recesses on edges). Dimensioning: D, B, L, E, S. The letter E stands for the rebate depth.

Burr or dovetail cutter

The milling cutter creates trapezoidal recesses that are used for dovetail joints . Dimensioning: D, B, L, α, S. The Greek letter α indicates the angle of the trapezoid sides.

equipment

A selection of accessories for routers:

Stops: parallel, side and angle stop
Clamping frame for stationary use under the table
Guide rail
Copier sleeve (also called copier ring or flange)
Copy button
Stencils
Chip suction device, chip collector
Vacuum clamping system
Centering mandrel
Circle device

literature

Guido Henn: Router manual: Select, operate, master. Vincentz Network, Hannover 2010, ISBN 978-3-86630-949-4 .

Web links

Commons : router - collection of images, videos and audio files