I'm in the process of building a second deck chair to match the one in this blog series.
The project is going much faster than the first since I have all of the required templates and jigs pre-made. The build process requires a number of bolt holes in the side assemblies to be drilled from the inside out. The holes require a counterbore on the outer surface. On the initial chair, I tried to line-up the forstner bit over the 1/4" drilled hole - this worked okay, but it was fiddly to get the bit centered. For this chair, I made a little centering jig.
It has a 1/4" dowel pin on one side and a counterbore on the other. With the pin inserted into an existing hole, the at-rest bit is lowered until it seated into the jig. While holding the bit down with one hand, I clamped the work down with the other. Raise the bit, remove the jig, and drill the counterbore. Worked like a charm.
It is purpose built for specific diameters for the hole and counterbore, so it will be stored with the jigs for this chair. I gave it a handle so it would look like a tool and not a piece of scrap that might accidentally get tossed.
Lazyman commented about 2 hours ago new Any easy solution. Is there a reason you cannot drill the counterbore first and use the Forstner bit's center for the location to drill the 1/4" hole?
That would be ideal, but the bolt hole goes through a floating tenon of a mortise that is cut on the inside, so there's bound to be a little bit of variability in both the mortise location and the position of the hole in the tenon. I know generally where the outer counterbore will be, but not precisely. If I drilled it first, I'd likely be off-center once the bolt hole was drilled.
