Router dos and don’ts

Avoid these five pitfalls for router success

By Steve Maxwell

No comments

Anything that spins at 25,000 rpm presents both great potential and great pitfalls. That’s certainly the case with routers. They let you create interlocking joints, decorate project edges and even duplicate parts with amazing precision. But to enjoy these benefits, you have to be aware of five hidden challenges and how to deal with them. Once you get over these, it’s easy to make friends with your router.

Don’t rout the wrong way

You’re not likely to make this mistake often, but it bears mentioning for beginners. Wood must always encounter the bit travelling against its direction of rotation. Since all routers spin the same way, success boils down to a simple rule: move all handheld routers from left to right; feed wood across a table-mounted router from right to left. Get this wrong, and the router bit will grab the wood and fling it instead of cutting cleanly. Climb cutting is a specialized operation in which wood is intentionally fed in the same direction as bit rotation. Although this technique has some benefits, it’s tricky and unnecessary. Don’t bother attempting it.

Don’t bite off too much

You can buy a brand new 31/4-hp router for $100, and with this much power in your hands, it’s tempting to rout too deeply in a single pass. But ease up, even if your router has the power. Any cut of 3/8" or more should be made with multiple passes; take even shallower cuts if the profile is wide or your router is smaller than 21/4 hp. Your router and bit will last longer, and the quality of cut you achieve will be better too.

Don’t rout too slowly

Cutters on a typical router bit hit the surface of routed wood about 800 times each second, and the potential for friction and heat buildup is high. The heat can cause burning on the wood, especially when you’re putting a decorative edge on hardwoods such as oak, maple, ash and beech. The solution is to reduce the number of cutter impacts on a given section of wood by moving your workpiece across the bit more quickly. Tip: rout all the wood off the edge profile except for about 1/32". Extend the bit enough to take this final, very shallow pass, then complete the cut quickly. The wood won’t even have a chance to get warm, let alone burn.

 

Do beware of a warped router tabletop

A flat router tabletop is good and a slightly crowned one is fine too, but a dished tabletop is bad news. That’s because it causes the location of routed edge profiles to vary along the length of each workpiece. Here’s how: imagine you’re milling a Roman ogee profile on the edge of a 36"-long drawer front and your router tabletop is dished just 1/16" in the centre. As the leading end of your drawer front hits the bit, it’s more or less tight to the table. But as you continue to push the wood farther along, the leading end of the wood rises as it climbs up out of the dished shape on the other side of the table. And as the wood climbs higher, it raises the middle part of the board in the process. This action causes your routed profile to shift 1/16" farther down along the edge of the wood than at the ends. The more intricate the profile, the more you will notice this shift.

One of the hidden causes of wonky router profiles is a warped router insert. A heavy router permanently suspended from a plastic insert can cause the insert to bend downwards over time. Use a high-quality metal insert or take your plastic insert and router out of the table between uses to keep it flat.

Do beware the bearing

Many router bits include bearings that guide the cutting action, but these often leave track marks on softwoods. Some marks show up only while staining, when it’s too late. Avoid track marks by using a fence on a table-mounted router, even when a bearing alone would do the job. Besides yielding mark-free results, a fence improves safety by covering most of the bit.

Honing router bits

Can you sharpen carbide router bits yourself? You bet. A diamond hone is the key. Any router bit with one flat face on each cutter is a candidate for mild DIY sharpening. Remove any bearing on the top of the bit, place the hone on the edge of your workbench, then run the bit’s cutter over the abrasive surface. Be sure not to rock the cutter as it slides. The tip of the cutting edges must not be rounded over in any way. Tune up bits at the first sign of dullness, and you’ll be surprised how much better they cut.


No comments

WordPress › Error

There has been a critical error on this website.

Learn more about troubleshooting WordPress.