So what is a "plunge router"? It is a router that is mounted in a spring-loaded base such that one can start the motor, position the router omn the workpiece, then press down and plunge the bit into the wood. One makes the required cut and relaxes the pressure on the router, and the springs lift the bit out of the workpiece. This makes the business of so-called "blind cuts" - cuts that don't start and/or end at the ends of the workpiece - very much easier than the old-fashioned "tilt the router into the wood" method we used to have to use to achieve the same cuts. So, this product. All the chewy goodness of a full-sized plunge router attachment in an accessory for the standard model Dremel rotary tool (mine's an old 395, the ancestor of the 4000). Comes with everything you'll need except bits and the Dremel itself. Years ago I bought a non-plunge router attachment for the Dremel that came with a straight bit as I recall; it's a shame one wasn't included in this unit. I've used that old router attachment to make hinge rebates in doors for example, for which it has worked very well. The instructions seem clear. You get a few nice accessories like guide bushings for template routing and a detachable edge guide. I've never been a fan of these myself, preferring a fence to an edge guide where possible, but sometimes the job calls for them. The edge guide has a fitting which, with the addition of a nail, makes the whole thing into a circle cutter. I used one of these on a full-sized router to make a ceiling rose out of some scrap wood once. A very cool use for the router. I haven't yet had a chance to use this tool, hope to do so tonight, but I've used a full-sized plunge router and cut circles with another and can say that practice is key for plunge routing with confidence and that working in slow increments of cut essential with a circle cutter. The only major downside for me is one I find in full-sized plunge routers all the time: the springs are too damn hard to compress in use. Yes you want the router to lift in and out of the cut, but if the springs are too strong I am wasting energy fighting the tool instead of concentrating and controlling the plunge itself. I bought my Sears router after looking at several "better" brands solely because the plunge attachment has springs just strong enough to lift the router but not catapult it off the workpiece when I release the locking knob. The plunge base has a twist-to-lock knob on one side so that once the cut is begun you don't have to worry about pushing down, and a two-setting depth gauge so pre-set plunge depths can be set up. I'm not sure how useful this will be for reasons I'll get to later. Full sized routers have similar features but they have motors with high torque which can be put under load safely. This is where things get a bit preachy. The Dremel tool has no torque to speak of, which means that it is very easy to overload and stall or burn out the motor at low revs if you aren't careful. The power of the Dremel comes from its extreme high speed. In addition, a 395 family Dremel (aka 4000 series these days) will be spinning at 35,000 rpm or just a smidge over 583 revolutions per second with the speed control hard over to max. The router bits I have are marked as "max speed 30,000 rpm" so running a Dremel-based router calls for less than full speed. Running at high speeds generates a lot of heat and with a small bit it is very easy to cook it. High speed steel (the usual inexpensive router bit medium) will lose it's temper and edge at the kinds of heat levels a Dremel can produce very quickly. I learned this 30 years ago when I ruined a drill in a block of wood when I got my first Dremel kit. Also, the winged pilot bits used to make fancy edging may chip and throw off debris if overdriven. They will also burn the wood. Running the Demel at less than max speed will drastically reduce the power it puts out, so a light and delicate touch on the workpiece will be needed if the motor is not to be stalled or damaged. So shallow passes must be taken, removing only small amounts of material before increasing the depth of cut and making subsequent passes. The secret with a Dremel as with any power tool is to pay attention to what the tool is doing and let the tool work at its own pace. If the motor is laboring, the tool is being abused. Forcing a Dremel through material will end in tears. You will see many reviews of Dremel router bits that bent when the owner tried to cut Maple, where the bit obviously overheated and the tool was forced through the cut. For softwood like pine or boxwood and very soft woods I think you might get very good results with little need to make shallow passes, but not burning the workpiece will, I think, be a challenge.
