A friend dropped by the shop with an interesting problem. The solution highlights a great use for a router.
- Here is the face of the kitchen clock, along with the old and new clock mechanisms.
The clock mechanism for his kitchen clock had finally succumbed to time and kitchen grime, coming to a stop. It was time for action.
My friend bought a new clock mechanism he wanted to use in the old clock body. Unfortunately, the new mechanism had a shaft 1/4″ shorter than the old one’s, and that shaft had to project through the hole you see in the center of the clock body on the left, in order to mount the mechanism to the wood.
- Here you see the clock mechanism mortise in the back of the clock body, along with the tool for making it deeper.
The 2″ square clock mechanism sits inside a mortise in the rear of the clock body. You can see it in the second picture. The problem was to neatly deepen the mortise by 1/4″. The solution was a router with a “pattern follower” bit.
A pattern follower bit is a straight bit with a bearing on the shaft, the same diameter as the bit itself. It’s like a flush trim bit, but the bearing is on the shaft of the bit instead of on the top. You can see one in the far corner of the mortise, and in the picture below.
Because the mortise already existed, I could use it as a template to cut deeper. I chucked a short pattern follower bit in a hand-held router and began cutting to final depth in the center of the old mortise, around the hole. This got the bit down far enough that its bearing would run against the existing mortise walls. Now it was just a matter of running the router clockwise around the mortise, deepening it right up to the old mortise walls. The edges were perfect, with no indication that I’d just cut the pocket deeper. Now, the new clock mechanism would fit easily.
Pattern follower and flush-trim router bits are very useful for duplicating shapes, and will probably find use in most woodworking shops. I have to admit that I don’t use a pattern follower bit often. But when I need it, nothing else will do the job.
