The Truth About Flush-cutting Saws
Flush-cutting saws offer an amazing promise: They can cut a dowel or tenon flush to its surrounding surface without causing any damage. The truth is, however, no matter how awesome your flush-cutting saw or how skilled you are, things can go wrong.
The most common problem is the saw can drift slightly. And with a flush-cutting saw, any drifting can be disastrous. The teeth can dive into the work after just a stroke or two. And this can happen even if you are doing everything perfectly. The wood can pinch the blade and deflect it down into the work. Or you can encounter some dense spots (perhaps a wedge in the tenon), deflecting the blade. Or you hit a patch of glue, which gums the teeth and changes the way the saw cuts.
After flush-cutting too many tenons to count in my life, I gave up on trying to cut things flush like they show it in the tool catalogs. Instead, my plan of attack makes things a little more complex, but I never have a saw dive into my work as a result.
The trick is a business card. I prefer thinner ones, but any card will do. Then I bore a hole through the business card that is slightly larger than the tenon. (The tenons shown here are 5/8” in diameter and wedged; a 3/4” hole works great.)
I slip the business card over the tenon then use that as a platform for sawing. If I chew up the business card, it’s no big deal. I throw it away and get another.
What’s left after sawing is a tenon that is about 1/32” or less proud of the surrounding surface. This is easy to take down with a plane or a file.
You might object to this method and say it makes more work. But I know that it saves time in the overall. I never have to fix a problem where the saw has deeply scarred the wood around the tenon. So on the whole, it’s a win.
— Christopher Schwarz
Editor’s note: Want to learn more about saws of all types and how to saw? Check out Chris’s “Handsaw Essentials,” available as an eBook at ShopWoodworking.com.