Router Maintenance and Troubleshooting


A router is a precision machine that is usually made to work extremely hard in adverse conditions, so it makes sense to try and prolong its life with a routine of regular preventative maintenance. Little and often is the key to keeping the router in good shape.

The main enemy is dust and debris and this then often gets mixed with resin deposits from the timber to form a hard deposit that sticks to columns, casings, screw threads and moving parts.

If you ignore it, the router becomes stiff and jerky to operate, the switch gradually seizes up, the cutters start jamming in the collet and all enjoyment in its use is lost.  Basic maintenance is not difficult and there is no need to dismantle the machine.

All you have to do is give it all a thorough cleaning on a regular basis. However, repairs are best left to a qualified service engineer particularly if the router is still under guarantee.


When cleaning the router don’t be tempted to blast it with a high pressure air line, as this just tends to force more debris deeper into the machine and could damage the windings and other electrical components as well as embedding dust into the grease packed bearings. Even with the use of extraction, dust is pulled into the router by the cooling fan so try and suck it back out through the ventilation slots with a vacuum cleaner. 

Do the same on the outside components of the router having first loosened it all with a small stiff brush. If the resin deposits are severe use white spirit or a proprietary resin remover to break them down, but keep these solvents well away from the internal motor parts and the plastic casings. Here is a checklist for more specific cleaning and maintenance.

Plunge columns

It is essential that the router plunges freely and without jerking, so make sure there are no sticky deposits on the plunge columns, scraping them off with a plastic scraper or a piece of stiff card. Never use wire wool or abrasive paper on these columns as this will leave scratches that actually aggravate the problem. Once clean, apply a coat of thin oil or preferably a dry lubricating spray (PTFE) to keep them sliding smoothly. Regularly check for side play in the plunge columns, any excessive play can only be cured by replacing the plunge bushes. Also make sure that the plunge lock operates smoothly and is not marking or burring the face of the columns.


The top and bottom bearings are packed with grease and sealed for life, so do not try and lubricate them in any way or you will do more harm than good. Potential bearing problems are usually first detected with your ears. Any change in speed and motor noise when it is free running, particularly intermittent noise, should immediately arouse suspicion. Then check for unusual vibration whilst cutting. Modern bearings are actually very reliable, but they have to work particularly hard on a router, so if you have any doubts have them changed immediately by a qualified service engineer, or you will end up with expensive damage to both the spindle and armature.

Although designed to accommodate high speeds, router ballbearings may require replacing during the life of the machine. The indications that replacement is necessary are as follows:

First check that this is not caused by a damaged cutter or worn collet. With the router isolated from the power supply and a long cutter fitted, apply pressure to the end of the cutter, any side play or vertical movement will indicate that there is a problem. If you are not sure, have the machine checked by a qualified service engineer.

Excessive noise
The ball-bearings will emit an abnormal noise level if they are worn or if the packing grease has solidified. In both cases replacement of both ball races are needed.


Physically check the spindle for play by trying to waggle it with a long cutter in place and feel for any rough spots as you turn it by hand. Make sure the router is unplugged!

Motor brushes

Most routers are designed for end users to change brushes themselves. Remove the relevant section of the casing or caps by unscrewing or removing the locating screws, using the correct type and size of the screwdriver. This will expose the brushes in their slides or holders. Take the opportunity to clean out any dust, using a soft brush (not a wire brush) and a vacuum extractor. Do not scrape the commutator surface and avoid damaging any of the insulated wiring to the field coil or armature. Disconnect the brush leads and gently lift the brush pressure springs to one side before sliding the brushes out. Clean out the brush slide with a soft brush. Do not use a solvent as this may dissolve the insulation on the motor windings.

If the brushes have worn severely, arcing may have occurred leaving carbon deposits on the commutator and brush slides. This can be removed carefully with a very fine grade flour paper, taking care not to touch the insulated windings (do not use wire wool as it will leave fine metal deposits that will cause further arcing and possible damage). Check that the new brushes slide freely in the slides, holding the pressure springs gently aside. Having inserted the brushes, reconnect their leads ensuring that spade terminals are full pushed home or screws are securely but not over tightened. Carefully replace the housing section ensuring that it locates correctly and does not pinch or trap any wires or components.
Having replaced the brushes, sparking may be apparent when the router is first used. This should virtually disappear after short use as the brushes bed themselves to the shape of the commutator and any loose carbon dust is burnt away.



Not all routers are designed for end users to changes switches themselves. When in doubt, arrange for an accredited Service Engineer to do this. Router switches are particularly susceptible to the ingress of fine dust. This packs around the electrical contact mechanism, preventing it from opening or closing or allowing the contacts to make only partial contact, leading to arcing and burning. In all cases, it is best to replace a faulty switch rather than to attempt to clean or repair it.

On some routers, it is necessary to dismantle the motor housing to replace or clean the switch. If this involves disturbing the bearings and motor assembly, it is best left to a service engineer.
Remove the housing section enclosing the switch, using the correct size screwdriver. Remove any cable clamps as necessary. Carefully note the wiring colour coding and to which terminal each lead is connected.
Release the screws or clips holding the switch in position and disconnect the leads at each terminal. Brush out the switch housing and check the condition and insulation of each lead. Check that all spade terminals are in good condition and show no sign of discolouration or burning, and replace if necessary, using the correct tool for crimping them or by soldering them to the leads, to ensure that adequate electrical contact is made. Fit the replacement switch, checking that all connections are sound and that all connections are made to the appropriate terminals.

Check that any electrical insulation is correctly fitted to prevent contact between the leads and that the wires are run prior to removal, to prevent them from being pinched or trapped by the casing. Ensure that the supply cable and lead are correctly and securely clamped before refitting the casing or cover.



We have already seen just how important the collet is for smooth and accurate running of the router and poor collet maintenance has been shown to be one of the most common causes of cutter damage and breakage. Regular inspection and cleaning of the slits of the collet is essential and you can now buy inexpensive kits that contain the necessary resin remover and corrosion inhibitor, as well as purpose made brass brushes for each collet size. This will remove any resin deposits or sawdust that could prevent the collet closing down evenly and gripping properly.

Warning signs are brown markings on the cutter shanks, shank slippage, bit or collet seizures and in extreme cases, shank breakage. Check that there are no burrs or scratches on the tapered faces and that the internal spindle taper and locknut thread are clean and undamaged, as these are all factors that can affect the security of the cutter in the collet. If either the collet or locknut is found to be faulty they must be changed as soon as possible. Do not use cutters with damaged shanks, particularly in new collets as this just transfers the problem. 

Clamp screws

All the clamping screws for the fence rods and depth stop should be fitted with anti-vibration springs to ensure that they don’t work loose whilst the router is running, particularly if you are not using the fence. The danger is that they gradually unscrew and then drop into the revolving cutter, so make sure the springs are in place and replace any that are missing.

Baseplate facing

The plastic facing on the router base is designed to ensure that it doesn’t mark the surface of the timber as you run the router over it. However it can quickly wear or become contaminated with resin. Any severe scratches can be flatted off with very fine abrasive paper wrapped over a flat block and resin deposits removed with a suitable solvent. Then spray the base with PTFE spray to help it slide freely over the workpiece.

Power cable

Constant movement of power tools can lead to fatigue and damage to the mains lead, particularly in the area where it enters the motor or plug. Like switch problems, this is often characterised by intermittent starting and running. Examine the cable and strain relief area carefully and replace if necessary. 


Remember that the continual heating up and cooling down from using blunt cutters can eventually affect the temper of the spring steel in the collet and reduce its elasticity. If you find that your collet is starting to need excessive tightening before it will grip, it is time to replace it.


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