Maybe the headline should read “The tool I hate to Love”. The adjustable circle cutter is what I use when I need something small or round. It is my fly cutter, and I don’t use it often. Its a simple device, but it looks scary, and for good reasons. It can do some serious damage if you dont follow the rules for using one safely. Here are my rules:
- These cutters come with a good grind, but a few strokes with the sharpening stones will give you a cleaner cut with less resistance.
- You should make sure all Allen screws are tight. One of the best things about this tool, is the ability to adjust the radius and depth of the drill bit as well as the knife.
- Double-check that all of the Allen screws are really, really tight one of the bad things about this tool is that everything is adjustable. If one of those screws comes loose while the tool spinning around, things can go flying. Hence the term fly cutter.
- Run the drill press at the slowest possible speed. On our Powermatic thats around 400 RPM, and I wish this machine could be set down around 250 RPM. I would feel better if it did.
- When the drill press is running, secure the work to the table. If something goes wrong, turn off the machine and duck under the table until the spinning stops.
- Feed the cutter into the work as slowly and gently as you can.
This tool is extremely dangerous, but you can still make clean, precise cuts with it, even when other tools fail you. To stick the 4-1/10cm-diameter slot, I needed a 1/20cm thick band of ebony. I wanted to use as little material as possible so I had six pieces mitered together and stuck down to a scrap of plywood.
My first thought was to use the same router that I used to make the slot, and different-sized guide collars with the same pattern I used to rout the slot. Attempt number one failed almost immediately when the pieces started coming off the substrate. Attempt number two failed very close to the end of the procedure. The thin strips were lifted from the bed and vanished into thin air after the final pass. The router bit exerts considerable force on thin strips, which is why there isn’t enough area to apply a removable adhesive.
Although I had considered using the lathe to make Plan B, I wanted a precise way to set the required diameters. As I formulated a scheme for mounting the bank to the headstock and marking and making the cuts, I remembered the fly futter stuck in a drawer somewhere. On to Plan C.
The cutter is reversible, so you can set it for either a clean inside or outside cut. The outside was cut, and then I reversed the cutter to adjust its position on the bar. Because the cutter comes to a sharp point, it can be set quite accurately. The results were excellent and I regret the time I spent trying to get it to work.
At this point, you may be wondering why on earth someone would need an 1/20 cm-wide circular strip of ebony. The image at left shows the ebony being glued and trimmed flush. But you will need to see the entire story in Magazine. Don’t worry if you are a subscriber. You can also unsubscribe by clicking this link.
