Tool Tips

How to Maintain A Plunge Router

Considering their incredible versatility and flexibility, it's not surprising that the plunge router ranks as the favorite tool in many workshops. After many hours of hard work, a few years of neglect, or perhaps an accidental fall off your bench, even the best built router will need some TLC. We narrowed the list of common plunge router problems down to 10 below.

Problem

Diagnosis

Fix

Prevention

#1 Plunging Imperfections
A smooth, comfortable plunge action makes for precise mortises and stopped cuts A plunge action that stalls on the downstroke is annoying; one that sticks on the upstroke can be dangerous

Release the plunge lock and then test the plunge movement. General sluggishness usually points to pitch build-up. If you feel a sticking point, inspect the guide rods. You're likely to find a dent left by a slipped wrench, or by that short "ride" off your bench

General sluggishnes: Clean guide rods with a toothbrush or fine abrasive pad. Lubricate bars with dry graphite or Teflon type spray. Apply lubricant to your cloth, and then wipe the guide rods

Wipe off pitch, dust, and chips before they build up. Keep the bellows clean and uncracked; they'll keep crud from reaching the rods in the first place. For table mounted routers, periodically disassemble the plunge mechanism to completely clean out sawdust.

#2 Banged-Up Baseplate
The baseplate, or sub-base, is the bearing surface between the tool and your work. Sticky buildup can hang up your router in mid-cut and burn an edge. A deep scratch can leave a sharp burr that will mar delicate surface.

Flip your router and run your fingers across the working face of the baseplate. Pitch streaks and burrs are tough to miss. Minor scratches are acceptable, but the baseplate should feel slick and smooth.

Pitch build-up: If you can't erase the crud with paste wax and an abraseive pad, try pitch remover. Wax the plate to make a smooth sliding surface
Burrs: Use a sanding block and 320-grit paper or a file to level any protrusions.

Make sure hardware, such as nails and screws are counter sunk below the surface before routing. Plan ahead for future mishaps by using a shop-made baseplate, or keeing a spare handy, just in case.

#3 Trashed Baseplate
Most factory baseplate opening are sized to hold guide bushings. However, a large diameter bit can damage the retaining lip of the opening, making it too big to hold guide bushings.

You can't miss the smell of routed plastic. Plungings a large router bit into a baseplate's small opening results in tearing it up.

Replace the baseplate
Note: Make sure to use correct screws. Using the wrong screws will ruin the baseplate.

Before turning on the router, take a test plunge. Invest in two baseplates: one for bushing guided template work and another for big bits.

#4 Bits That Slip
When a bit creeps out of the collet, regardless of how tight you torque the collet nut, you've got a problem. A slipping collet makes it impossible to rout a consistant cut and can damage the shanks of your bits. Even worse, it can fling the bit, creating a dangerous missile in your shop.

Dark marks, or rings, around the shanks of bit are a solid sing that the bits are spinning slower than the motor.
You can quantify collet wear by using a dial indicator to measure run-out, but first you should try wiggling the arbor to make sure it's not a bearing problem.

Remove pitch buildup or minor surface rust with a brass collet brush
Note: Don't use sand paper to make this fix. Sanding the collet or bit shank can remove too much metal and prevent a secure grip.

Keep the collet clean. Minor dust and rust can cause major damage. Blow or brush the collet out when changing bits. Oaktree Tools  offers great router bits for you to use to help your router perform at its best for years to come.

#5 Frozen Collet Nut or Bit
The reverse of bit slippage, a collet nut may lock onto the armature, or a bit may stick in the collet.

Try as you might, the bit refuses to come out

Give the wrench a light whack. Make sure you're turning the nut in the right direction. Be careful not to damage the bit or plunge rods in the process.

Do not overtighten the collet nut, or tighten the nut without a bit in place. To do so could permanently deform the metal.
Clean threads with tooth brush. Wipe on a thin coat of lubricant, and then wipe off any excess
Note: Do not lubricate the inside of the collet. If you do, it won't grip the bit.

#6 Plunge Lock Lever
The plunge lock lever fails to hold its cutter depth. It turns without achieving the necessary grip; or worse, the router springs up in the middle of a cut

With the router motor end up, plunge the base halfway and lock it in place. If you have router table, repeat the test base end up. Any movement means a loose lock lever.

Check the guide rods first; make sure they are clean of any residue. To tighten the plunge lock lever, remove the retaining screw, pull off the lock lever, and adjust the lock bolt.

If it ain't broke, don't fix it. Most lock problems can be traced to earlier attempts at a quick fix when the real problem may have been dirty guide rods or a slipping bit.

#7 Worn Brushes
The brushes in your router are chunks of carbon that deliever current to the motor by brushing against the commutator. Over time and use, they wear out.

You may notice a decrease in power, see a shower of sparks, or detect an electrical smell. If the brushes don't have a wear limit mark, it's safe to assume that they're nearly at the end if there's less than 1/4" of carbon.(Uneven wearing or chipped brushed may indicate a problem with the armature). If one brush goes completely, the motor will shut down.

Remove the brush holder caps, take out the worn brushes, and insert the replacements. Replace both brushes at the same time, being careful not to crimp the springs. After installing, run the router for 20 minutes to give the new brushes a chance to seat themselves against the commutator. Some models conceal the brushes behind the motor housing.

Average brush life varies from 50 to 100 hours. Even if you use your router regularly, you won't need to check the brushes more than once a year; pros may do a check every 6 months

#8 Suspect Cords and Plugs
Compared to other job-site tools, like circular saws, you're not as likely to accidentally cut the cord, but normal wear and tear still take their toll. At best, a damaged cord will kill your tool; at worst, it can kill you.

Check the cord. A cracked sheath, missing ground prong, or wires protruding where the cord meets the housing tells you it's time for replacement.

Replace cord

Choose routers with rubber cords; they maintain their flexibility longer than plastic. To avoid stressing the sheathing, wires, or connections, coil cord loosely, especially where they attach to the motor. Never yank a plug from the outlet or leave a plug where you could step on it.

#9 Trigger Troubles
More likely the result of a fall than mechanical failure, a switch that won't turn on or off deserves immediate attention.

Router fails to start or stop, or runs intermittingly.

The complexity of replacing a switch varies by model and manufacturer; if in doubt, take it to repair shop. In the case of simple three-wire on/off switches, note the wire colors and locations before removing the old switch, and replace the new switch one terminal at a time. Be careful not to pinch the wires.

Switches are tested to survive thousands of on-off cycles. You can minimize any further chance of problems by blowing out fine dust that can compromise electrical contracts.

#10 Bad Bearing
High RPM routers are tough on bearings; but unless you're working in a heavy use commercial shop, you may never encouter a problem. Bearing are designed to run for 300-400 hours, the rule of thumb is to replace them with every other brush change.

Worn bearing may make a popping, cracking, or grinding noise. Feel for heat. Rubbing bearings can raise a router's temperature and may even make it too hot to handle. To check your initial diagnosis, unplug the router and turn the arbor by hand. Any perceptible drag, wiggle, or looseness signals trougle.

Bearing replacement

Bearings wear out fast when they are not under load. Leaving the router on between cuts can be a problem with table mounted routers. To avoid leaving the tool turning, install a foot pedal to your router table so it's easy to switch off between cuts.