Thought I was slick setting up a homemade jig for my CNC, then the bit snapped

Back when I started out about 4 years ago, I used to just clamp everything down with whatever I had and hope for the best. One time I was routing some oak sign blanks and the whole piece shifted mid-cut, ruining the piece and throwing chips everywhere. Now I take the time to build a proper vacuum jig for each batch run, even if it adds 20 minutes to setup. It's night and day for repeatability and I'm not chasing parts across the shop anymore. The change happened after I had to scrap a $200 sheet of walnut because my workholding was lazy. Anyone else have a jig fail story that forced you to change your whole approach?

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the_tara6d ago

Wait have you ever thought about how your jig setup might actually be fighting the natural forces in your material? I'm not talking about clamping pressure or vacuum hold down, I mean the internal stresses in the wood itself. When I switched to using a stabilizing base coat of shellac on both sides of my stock before routing, I saw way less warping and shifting during cuts. The shellac seals the moisture content so the wood doesn't try to cup or twist as I'm removing material. It's not a jig per se, but it stopped my workholding failures because the wood wasn't fighting me before I even touched it with the bit. Sounds counterintuitive to add an extra step, but it saved me from a snapped bit more than once when I was being lazy about prep work.