This week there came a need to rout an oval that matched a smaller oval, and we needed to make the new pattern 1-1/4″ wider all around. A new design could have been made, but that’s a lot of extra work to layout, cut and shape. And getting the oval as an exact match would be difficult at best.
In the past (especially when working on goose-neck molding layout), I’ve made a wooden circle with a center hole just sized to allow a pencil to pass through to accurately draw around a pattern, providing a perfect over-sized pattern. As we discussed this technique, Dave (friend and fellow woodworker) suggested we bypass the pencil and use a router bit instead. Great idea.
To make it happen, you need to size the needed bushing. To add 1-1/4″ when using a 1/4″ spiral-upcut router bit, you need a 2-9/16″ outside diameter bushing – you cannot find that in the router accessories department of any store. So step one is to make a plywood disc to that size. If you do the layout work with a compass, you get the size and you mark the center of your disc, which is a good thing. Cut the rough shape at your band saw then smooth the edges using a disc sander. (You could set up a band saw jig to make the disc, but that’s way to involved when a single disc is needed.)
With the wooden disc in hand, drill a hole in its center that is perfectly sized for a standard bushing you have in the shop; in this case, we used a 3/4″-outside diameter bushing. Make sure you accurately center the hole in the disc – that’s where the prick from the compass leg comes into play. When you’ve drilled the hole, the disc should fit snug on your bushing. Load the over-sized guide bushing into your favorite router and your set to work.
With this arrangement, the bushing offsets the router as the cut is made. A good practice is to step your way through these cuts, making several passes while dropping the cutting depth with each step. The photo below shows the first light pass, which also confirmed the offset cut.
Router bushings are a great asset to have in the shop. In most available kits, the largest outside diameter is 51/64″. You can find odd bushings sized as large as 1-3/16″, but if you need something larger, turn to plywood and make the bushing in your shop.
Build Something Great!
Last week I worked on the arched moldings for my clock and left you with going back into the shop to used different setups and a new design. It worked. Kind of. It turns out that I did use my Micro Fence circle-cutting jig, but I had to also use my shop-made jig, too. The Micro Fence system did not allow me to get as small as I needed to make my moldings. The opening photo is that of the second profile as it came off the router. (You can enlarge the photos if you click on them.)
This week I began from the profiled arched moldings. Three things to do: cut the arched pieces from the stock, make a set of straight moldings to match what I had in the arched set and work the small bead of the moldings. At the band saw, I cut away the waste to free the almost completed arched moldings. A quick trip to my disc sander (the outside edge) and my spindle sander for the inside edge and I was ready to begin matching the profile on some straight stock.
One of the ends of each of my four arched moldings is square cut – the ends that met in the middle of my setup. Using that end, I worked through the profile using the same router bits used to make the arched pieces. I had to set the depth of cut and the fence location to accurately match the design. It took about two hours to create a matching design on my straight stock. The last cut was the 1/4″ round-nose bit profile. With its work complete, I could rip the molding pieces free.
The last step was to create the 1/8″ bead on each of the sticks of molding. My first thought was to carve the pieces. I grabbed a small, bent-back carving gouge from the roll and got ready. After a couple minutes, I knew this was not the answer. Plan B – which should have been Plan A in retrospect – was to make a scraper for the task. Simple enough. I drilled an 1/8″ hole near the edge of one of my scraper blades, then ground it (sanded it with my spindle sander) so only half the profile showed. Work began on a straight piece of stock. Scrape. Scrape. Scrape. Done. It was too easy. The second, third and fourth pieces of straight molding went just as quick. But what about the arched pieces? I clamped one in my vise and went at it. The results were just as great and just as quick. The finished molding is shown above right, and the process is shown below. (The inset photo is the bead scraper.)
If you run into this need, make a scratch beader your Plan A. It’s way easy to do. And it works.
Build Something Great!