Typically, when you get chatter on a lathe project, it’s a bad thing, leaving unsightly marks you have to cut or sand away. With a chatter tool, you can control the chatter pattern and make it decorative, instead of a mistake. The tool comes with interchangeable cutters that will produce a variety of patterns.
This article will give you an overview of how the chatter tool works and how you should use it. In order to avoid throwing too much chatter, and too many variables, at you at once, I’m going to concentrate on just one of the four cutting profiles the tool comes with, giving you recipes for setup to make it easier for you to chatter forth on your own.
The chatter tool works a lot like a scraper, and it is sharpened similarly. Sharpening can be done on a fine grinding wheel or by hand. The burr produced by sharpening helps the chisel cut, and it should be left on the tool.
Position the Tool-rest
Typical lathe turning has you keeping the tool-rest as close as possible to the work. When using a chatter tool, you’ll need to have the tool-rest backed away from the turning. Cantilevering the tool past the rest so it can vibrate is the very thing you’re trying to avoid with a conventional chisel, but it’s what allows a chatter tool to work.
Start with the tool-rest above the center line of your material so the chisel is angled downward when it cuts. Changing the elevation of the tool-rest is one of the variables that changes the resulting chatter: it’s something with which you’ll want to experiment.
Make the tool-rest parallel to the end grain you’re working on so you can do a chatter start to finish in one fluid motion.
What Chatters, What Doesn’t
Chattering works on the end grain of hardwoods. Period. Believe me, I’ve tried face grain, and I’ve tried softwoods. It just ain’t gonna happen. The material simply isn’t rigid enough to withstand the force of the chatter tool. Instead of chattering, it ends up tearing. Your best bets are close-grained woods like maple, cherry, walnut and rosewood.
Before chattering, you should face the end grain off so it’s smooth. My preferred method for this is a shearing cut with a 3/8" bowl gouge.
Four Chatter Setups
Here are four setups, all using the same cutting tip, that create four different patterns. All were cut in hard maple at 1,000 rpm. This will provide you with a recipe for doing your own chattering, but remember that this is more of an art than a science, and it’s nearly impossible to perfectly duplicate a pattern.
Probe With The Point: Push the V-shaped point into the material in evenly spaced intervals, leaving about 1/8" between each cut. Then go back and probe again, hitting the uncut spots.
The result is a herringbone pattern. The chatter looks best if you leave uncut areas next to it for contrast.
Long Edge, Right To Left: Engage the straight edge of the cutter against the material and pull the tool from the center toward the outside. This pattern is of fine lines.
Long Edge, Left To Right: Use the long edge again, but move the tool from the outside toward the center. The result is a slightly counterclockwise spiral.
Tip Only, Light Touch: Make contact with the Vshaped point, hold the tool rolled slightly toward the right, and move from the outside to the inside.
The result is a pattern that resembles a weave. Increase the rpm to get a deeper, more widely spread pattern.
Seven Chatter Techniques
Again, this is more art than science, so don’t try to make it too formulaic. Here are a few guidelines to get you started:
1) Low rpm results in finer patterns, high rpm results in bigger patterns.
2) A high-pitched squeal means you’re making a good chatter (be sure to wear your hearing protection).
3) Allowing the cutter to project farther from the tool creates a heavier, more widely spaced pattern. Start with the cutter extended about 1".
4) The tool should angle down slightly toward the work.
5) Cutting on center makes a pattern with lines that radiate straight out from center.
6) Cutting below center makes lines that spiral clockwise, while cutting above center makes lines that spiral counterclockwise.
7) Leaving some spots unchattered creates a visible contrast, which will highlight the textured work.
This is a lot of fun, and can add a unique touch to your turning projects. So, chuck up a hardwood blank, chatter it, face it off, chatter it again, face it off … you get the idea. Once you give it a try, you’ll be chattering up a storm.