Years ago, when I was woodworking as a full-time occupation, I remember a couple jobs in particular that required me to set up a drill press to drill a sequence of holes where accuracy was a must. One job was producing prototype cabinets for JBL, the company that makes speakers. The cabinets were intended to be “knock down” so fasteners could be inserted and align perfectly for assembly. The blueprints they supplied called out hole centers like 7.312″ then 12.855″. There were dozens of these. This job is where I became familiar with dial calipers. I also took some advice from a more experienced woodworker. I complained to him about working to such finicky dimensions. He said, “If you can drill precisely to 5″ or 10 3/4″ then you can drill precisely to any number expressed in thousands of an inch.” Point taken.
The second job, which lead me reconsider self-employment as a cabinetmaker, was constructing 13 weaving looms ranging in size from a smaller tabletop model to large floor models with five harnesses, you know, the kind you sit at. It was the job of 10,000 holes for each one, or so it seemed. Ugh!
I recently built a drill press table for our shop that was in the April issue. As part of that story I posted a short video on the subject of how to drill repetitive hole patterns with a high degree of accuracy. This may not break new ground for some of you, but I suspect there are others who will find it helpful.