6 Tips for Router Resuscitation

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This article is from Issue 94 of Woodcraft Magazine.

Maintenance and cures for an ailing tool

For many woodworkers, the router gets the hands-down vote as the most capable and convenient portable power tool in the shop. Whether handheld or mounted in a table, it excels at tasks ranging from profiling edges and cutting joints to pattern-routing and creating decorative inlays. The tool’s design and engineering are just as impressive as its multifaceted usefulness. Considering all the tricks this workhorse can perform, it’s not surprising that it requires regular care and occasional first aid.

I’ll first touch on preventive maintenance and then run through six potential problem areas to help you diagnose router ills and perform the necessary cures. Use the illustration on this page to locate the key problem areas on your router. To assist with the inspection and repairs, I’ve prepared a router “first aid kit” consisting of the items listed in the sidebar on the next page. Finally, should the repair be too major, I’ll steer you to the nearest tool service center for professional help.

1 Preventive maintenance

As part of your router’s health care program, preventive maintenance can help ward off problems due to normal wear and tear. Surprisingly, fine dust and debris are your router’s worst enemies. They can lead to switch failure, accelerated brush wear, and overheating. It’s a good practice to regularly blow out accumulated debris with low-pressure air. (High-pressure air from a compressor can force dirt into previously uncontaminated parts.) A quick visual inspection before each use will help you identify developing problems.

When a router ailment causes poor performance or no performance at all, it’s time to reach for the first aid kit. Always unplug your router before making any repair.

First aid kit. Use the tools and supplies in this kit to keep your router running smoothly and efficiently.

Switching out a switch. To install a new switch, orient it properly and reattach the wires in their original configuration.

2 Switches and electronic controls

A power switch or speed control that has been compromised by accumulated dust and dirt may cause a router to run intermittently or not at all. Closely examine these parts and their cord connections and try cleaning them with low-pressure air. Then test the tool. If the problem persists, you can order a new switch or speed control and replace the parts as shown. Alternatively, you can ship your router to a service center for diagnosis and/or possible part replacement and repair.

Quick Tip

When disassembling a tool for repair work, take photos of the wiring, hardware, and part arrangements for reference during reassembly.

3 Power cords and strain relief

A missing prong or cracked plug can be easily fixed. Replacement plugs, like the one shown below, are available at most hardware stores.

Damaged cords can be more difficult to diagnose. Misuse, wrapping the cord too tightly around the router, an accident, or old age can expose or sever the conductors within the cord’s outer sheath or loosen the connections at the plug or switch. If you can see bare wire, it’s time to replace the cord. If the cord appears to be intact, you can sometimes pinpoint a trouble spot by powering on an unarmed tool and then wiggling the cord. Broken conductors can cause a router to run intermittently as the cord is flexed.

When replacing a damaged cord, solder the wire ends or install “crimp-on” connectors before tightening the terminal screws. Note and follow the cord’s color code for the wiring. In the U.S., green is the case ground, white is the neutral, and black is the “hot,” or powered, wire.

Plug replacement. Assemble the plug, making sure the black (hot) wire connects to the darker brass screw.
Correct cord connections. At the motor, carefully fit and screw the tinned wire ends of a replacement cord under the terminal screws, paying attention to the wire’s color code. Tinning results in a better mechanical and electrical connection.

Brush replacement. Always replace brushes in pairs. A hemostat clamp works great for maneuvering brushes, springs, and connecting wires.

4 Brushes

Manufacturers recommend checking brushes every 50 to 100 hours of running time. This isn’t easy to track, so make a point of checking brushes once a year or before starting a major job. Brushes typically need replacing when worn to one-fourth of their original length. If your brushes don’t have a wear line, consult the manual or check with a service center for minimum length specifications. Signs of impending brush death include increased noise levels and excessive sparking. Ignoring the problem for too long risks damage to the commutator’s soft copper surface.

On some routers, the two brushes sit under threaded plugs in the motor end cap. On others, the cap itself must be removed to expose the brush holders. With the brushes exposed, disconnect the brush’s electrical connection and carefully reposition the end of the spring that presses the brush to the commutator.

After removing the brush, blow away any carbon dust on the commutator, and then inspect it with a strong light. A healthy commutator should reveal a clean copper surface. If it appears burned or excessively worn, get a repair estimate from your service center.

Fit a new brush in each holder, and reconnect the pigtails. Make sure the brushes contact the commutator and move freely in their holder. Reassemble the parts and test the router.

Quick Tip

If brushes removed for inspection don’t need replacement, be sure to reinsert them in their original orientation.

5 Locks, stops, and plunge mechanisms

Routers employ a variety of locks and stops to position and guide the cutter. These function best when they are clean, lubricated, and properly adjusted.

On fixed-base routers, a locking mechanism secures the motor in the base while allowing depth-of-cut adjustment. Whatever the particular mechanism, clean and lubricate it occasionally to ensure smooth operation. On some routers, a pin projecting from the motor casing rides in a spiral groove in the base to raise and lower the motor. These grooves need occasional cleaning as shown in the photo below.

Plunge routers employ telescoping tubes with internal springs that allow the cutter to be plunged into the workpiece. The mechanism should operate smoothly without catching or wobbling. The plunge lock should engage easily and hold the depth of cut securely. Any problem with the plunge mechanism usually stems from an accumulation of dirt and debris. The fix is to disassemble the moving parts, clean them, and then apply dry lubricant prior to reassembly.

Mechanical depth stops allow presetting the maximum depth of cut. For trouble-free operation, clean them as shown at bottom left and apply dry lubrication such as Bostik DriCote (Woodcraft #124626).

Metal hygiene. Clean the spiral height-adjustment grooves using a toothbrush and rag dampened with pitch remover.
Plunge bath. Disassemble a depth-stop rod and turret to properly clean and lubricate them, ensuring smooth plunging operation.

Stripped Screws, Broken Castings, And Missing Knobs

Router castings are made of strong, lightweight materials like aluminum, but they’re not indestructible and may crack or break when dropped. To reduce the possibility of breakage, surround your workbench with rubber mats to soften the blow when a router or other tool falls to the floor. You can repair minor cracks with J-B Weld epoxy or similar metal repair products. However, if a casting is completely broken, gluing the part together is risky; order a replacement.

Stripped screw threads in aluminum castings are another common problem. Used for attaching sub-bases or accessory fences, these threads can strip out if you over-tighten or cross-thread a screw. To “fix” stripped threads, you can either redrill the holes and tap them for a larger size screw, or drill and tap a new hole at a different location to serve the same function. Alternatively, you can replace the casting. In any case, never operate a router with broken or missing parts.

6 Collet, cutter, and bearing problems

The business end of a router consists of a removable sleeve called a collet that fits into a chuck, or tapered recess, in the motor’s shaft. Tightening the collet nut forces it to grip the bit, holding it securely for a routing operation.

If you encounter rough cuts when using a sharp, high-quality bit with a clean, unmarred shaft, the problem may be caused by a dirty or worn collet and/or chuck, which can allow bit slippage. Use pitch remover to clean the collet, chuck, and nut (right). Scrutinize the nut and chuck for damaged threads, and replace the nut if needed. Inspect the collet for rough edges, which can be lightly smoothed with 400- or 600-grit wet/dry sandpaper. If your router has additional collets, clean and check them as well.

Excessive tightening of the nut can deform a collet, reducing its grip and allowing bit slippage. Worst case scenario is that a spinning bit could drop from the router. Telltale indications of collet and bit slippage include galling and score marks on the bit’s shank. In some cases, simply cleaning the collet and chuck with solvent and steel wool will remedy the problem. But if the collet surfaces are rough or rusted, replace the part. On some routers, the chuck is actually a separate part that threads onto the end of the spindle. Special tools may be needed to remove it, possibly requiring a trip to the repair center.

Spindle wobble, or runout, can also cause rough cuts. Check for runout using a dial indicator pressed against a centering bit or a short piece of appropriate-sized drill rod (from industrial supply houses such a McMaster-Carr or Fastenal) chucked in the collet. A dial indicator with a magnetic base as shown top right requires a ferrous attachment surface. To create one, use double-faced tape to attach a tablesaw blade to the router’s sub-base covering the blade’s teeth with tape for safety.

With the dial indicator shaft pressed against the bit about 1" above the collet nut, rotate the shaft by hand and note any movement of the indicator’s dial. There should be little or no runout (.001-.002). Excessive runout could indicate bad bearings that require professional repair or replacement of the tool.

To check for bad bearings, remove the nut and collet and turn the motor shaft by hand. It should rotate smoothly and with no discernable side play or noise. If you detect a problem, weigh the costs of repair versus replacement. 

Cultivate crud-free collets. Clean the collet and nut to remove dirt and debris and keep them trouble-free. 
Turning true? Use this setup of a dial indicator, saw blade, and drill rod to check collet runout.

Where To Turn For Help

Most major manufacturers’ websites will point you to your local authorized router service centers that can help you asess your service needs. Alternatively, call the manufacturer directly using the following numbers.

Manufacturers’ Numbers:

Bosch (877) 267-2499
Craftsman (800) 549-4505
DeWalt (800) 433-9258
Festool (888) 337-8600
Freud (770) 458-0870
Hitachi (800) 448-2244
Makita (800) 462-5482
Milwaukee (800) 729-3878
Porter-Cable (888) 848-5175
Rigid (800) 474-3443
Ryobi (800) 525-2579
Skil (877) 754-5999
Triton/HTC (800) 624-2027


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  • AS from Sandusky
    You musta' sensed me comin'! I just got my father's Craftsman router/table out to clean up and try to use! - Sixth sense!
  • JS from Spirit Lake
    Generally speaking I think having a router professionally repaired is a good idea only for the high end routers. Repair costs tend to be so high that it is less expensive to get a new router. This would mostly apply to the 2-1/2 hp and smaller.
    Pitch the router and use hand tools instead!!! Make Roy Underhill proud! Your family, neighbors, ears, and lungs will thank you.

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