Bishop Cochran Guitars Plunge router base

Model Airplane News, Nov 1998 by Gimlick, Greg

Detail work made easy

IF THERE'S ONE tool that almost every modeler has in his or her shop, it must be a Dremel tool or one similar. Just when I thought I had every available accessory to make my life easier, here comes the Bishop Cochran Guitars* Plunge Router Base, which converts the fixedbase Dremel tool into a true plunge router.

Bishop Cochran is a guitar builder who couldn't find the right tool for doing fine inlay work and rosettes, so he designed his own. The very sturdy unit is machined out of anodized aluminum with 01 premiumground steel posts and guides. If you've used a plastic router attachment, you know how it can flex and loosen, but the Cochran base has a beefy feel and absolutely does not flex.

The Dremel tool is mounted by removing the plastic threaded collar and inserting it into the base, where it is screwed into the bottom collar. The top of the tool is held firmly by a clamping upper support; that's all there is to it. To change the depth and fence guides, simply loosen the locking levers and adjust the guides. There is a provision for micro adjustments in height and fence depths, so you can fine-tune them to your application. Of special note is the use of small brass "plugs" in each threaded hole where adjustments have been made, so the locking screw won't mar the support posts when it's tightened.

THE BENEFITS

You can position the plunge router exactly where you want and then lower the cutting tool into the work. The tool won't waver or elongate the hole, and you can make a very precise cut. Here are some things I did in just a few minutes, with excellent results.

I've cut slots in foam wing-cores to accept spars using a hot wire and template, but that required that I cut the slot the full length of the core.

Using the Cochran base, I placed a steel ruler on the core and positioned the router against it to use as a guide. I set the vertical stops to allow the cutter to go only as deep as I needed for the spar material and began to lower it about 3 inches from the end of the wing, where I wanted the spar to end. The router is so strong that I easily controlled it with one hand while I held the ruler/guide with my other hand, and cutting an exact slot took less than 5 minutes. With the right cutter and the depth set with the vertical stops, I ended up with a clean, straight slot with a nice, square bottom. I did the same thing in a sheeted core, and it was even easier.

My next operation was to cut around servo hole in the foam core to accept a round, European servo-mounting system. Ordinarily, this would be a nightmare, but it proved to be as easy as the straight cut. I flipped the fence guide over so the circle guide was toward the work surface and set the radius of the circle using the horizontal adjustment knob. When I knew where I wanted the circle to be, I pushed the circle guide into the foam and rotated the tool around it. I expected some drift in the foam, but the base is so solid that it wasn't a problem. When the outline hole had been cut to the depth I wanted, I removed the fence and routed the excess foam from the center of the circle.

Next, I routed windows into mock fuselage sides (using old Formica templates) and trimmed leading and trailing edges. One of the key elements to making the most of this tool is to accumulate various small router bits and bearing guides; if you can't find the 1/88-inch shaft you need, a machine shop can cut one down for a small fee.

When I first heard about this base, I thought, "Gee, that's expensive," but after I had used it for a couple of weeks and compared it to other available bases, I changed my tune. It's custom-made for detail work. If you're looking for a high-quality tool that will outlast your Dremel, this is the base for you. Bishop Cochran is available via email or phone for technical help and is develop ing a base for Ryobi tools, too. Am I impressed? You bet!

*Addresses are listed alphabetically in the Index of Manufacturers on page 126.