Plunge Routers - key features
A router can be one of the most versatile woodworking tools, but with all the different makes/models on the market, it essential that the correct router is chosen. This article gives a brief summary of the features which need to be considered.
In basic terms, the more power a router has, the better it can cope with harder materials, larger diameter cutters and deeper cuts. However the power also largely dictates the size and weight of the machines, so consider the use for the router when choosing. A large, heavy, powerful router would be a difficult to handle for very light, delicate work.
As a rough guide to classifying routers, models of 400 to 600W are for light duty, 750 to 1200W are for medium duty, and 1250 W upwards are for heavy duty.
Machine speed can range from about 800 to 30000 rpm.
Nearly all modern routers have variable speed motors, the setting is by a simple numbered knob showing up to 5 or 6 positions. The required speed will depend upon the size of cutter being used and the material being cut, the appropriate speed setting for any combination will need to be determined by trial and error/experience. The variable speed control should not be in a position where it could inadvertently be changed while routing.
Generally there are two side hand grips on the motor housing. They should be positioned as near to the base plate as possible to give good operator control and balance. The handles should be nice and bulbous so that they feel comfortable in the operators hands.
The base plate positions the cutter at right-angles to the workpiece, in some operations the side of the base plate is run along a straight edge, so at least one side must be straight.
The underside of the plate often slides over the workpiece, and it is necessary to do so without marking it. Most plates have a thin plastic facing underneath, ideally this should be replaceable, and spares should be available.
The size of the collect determines the size of cutter shank which can be fitted. Various collet sizes are available - 6, 6.35, 8mm, 1/4, 3/8, 1/2 inch. The size fitted as standard to a model should depend upon the power of the machine, light-duty routers will probably have a 1/4 inch, medium duty 3/8 inch and heavy duty 1/2 inch.
Collet reduces are available to that different sizes can be fitted in the larger machines.
To change a cutter, normally the spindle of the motor needs to be locked and an open ended spanner used to release the collet. The spindle lock is a simple push and hold mechanism that stops the spindle turning when the spanner is used to release the collet.
Some routers do not have spindle locks but require two open ended spanners, one to hold the drive spindle while the other releases the collet.
Plunge is the change in height which the router body will descend to the base plate, on some machines this actually projects the collet below the base-plate - useful in some cases. Plunge depths vary between models, it can range from 2 to 3.5 inches.
It must be remembered that the plunge depth may not be a realistic working depth below the bottom of the base plate. If the bottom of a cutter is, say, 1/2 inch above the bottom of the base-plate when the body of the router is up, this effectively reduces the plunge depth by 1/2 inch.
(aka depth stop)
The plunge stop is adjustable and limits the maximum depth that the cutter can go below the base plate. It can be set by either a simple finger tightened knob or a spanner tightened arrangement - the finger tightened knob is easier but you need to make sure that it does not become loose during operation thus losing the setting. Whichever type of stop is fitted, it will need to be checked/adjusted every time the cutter is changed.
Most depth stops have some form of depth gauge, but this is not an absolute measure as the position of the cutter in the collet is not taken into account. When setting a depth, it is always worth checking it by routing into a piece of scrap before working on the actual workpiece.
Some routers have a twistable turret stop mounted on the base plate, this normally has three adjustable (in height) screws, the depth stop coming to rest on any one of them at one time. By setting the separate screws to give different cutter depths, up to three depths can be used on a job without having to adjust the depth stop, just by turning the turret.
The plunge lock locks the depth of the cutter and is normally incorporated in one of the hand-grips, a simple twist action. Alternatively it may be a simple level located adjacent to one of the hand grips.
Side fences are supplied to facilitate edge trimming and moulding using non-self-guiding router cutters. They also enable cuts parallel to the edge of work pieces to be made. The position of the side fence can, on some routers, be finely adjusted using a turn screw while other just slide along two parallel rods mounted through the base plate and have locking screws.
Most routers are now supplied with a dust extraction hood which is positioned around the cutter. A separate dust extraction vacuum unit needs to be connected to the hood to remove the waste.
A template guide normally fits under the base plate and projects a short sleeve downwards, it is normally held in place by two or four screws into the base plate. The outside of the sleeve is used to guide the router around a template which is either smaller or bigger that the required final shape.
Different diameter template guides are necessary for using different diameter router cutters, so a selection of guides is an advantage.
Some manufacturers offer routing tables to suit their routers. The router is normally fitted upside-down with the cutter projecting above the table surface so that the workpiece can be laid on top and, normally, run against a fence across the cutter.
Routers normally need little maintenance other than keep it clean, check the vacuum attachment hole as sometimes small strips can become lodged and reduce the extraction of waste.
Keep the air vent holes of the motor unobstructed otherwise the motor may overheat. If dry saw dust gets inside the motor, sparks from the motor brushes can ignite the dust.
If you use your router a lot, the motor brushes will need changing, this can be fairly easy if they are accessible on the outer case. It may be justified to occasionally have the router fully serviced so that the inside can be cleaned and any damaged bearings replaced.