Jig for recessing a 1 3/8" ring on a 30mm hole

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This is an overcomplicated mess that just happened to work for me. There's probably much easier ways to do this, but I'm not experienced with woodworking at all, and don't own a more complicated drill guide. So here's what it's for: I have a gameroomsolutions pinball cabinet. They pre-drill the holes for the front panel (like "Start", "Exit", etc). They pre-drill them horizontally instead of vertically, which may seem fine, but if you do any nudging at all you're going to bump into the buttons. There are a few ways to deal with this. I had considered puttying over the holes and re-drilling some vertical holes. I had also considered a different style of button that may be less prone to activating during nudges. What I ended up deciding to do is recessing the buttons so that they are flush with the face of the cabinet. There's a lot of ways to screw up when doing this, made no easier by the fact that there is only a difference of 5mm between a 1 3/8" cut (used to recess the buttons) and the pre-drilled 30mm cuts. Getting the drill exactly center, keeping the drill level with the face of the cabinet, and drilling exactly 3/8" deep, are all somewhat difficult to do without some sort of guide. I'm sure there's better ways to do this, but I ended up making this jig. Note that I had to do a ton of sanding/filing on the nut to get it to fit. I don't know if I screwed up in the modeling or my 3d printer tolerances are just terrible, but it took a lot of post processing to get the nut to screw onto the jig. Here's how I used it: I printed all the parts first. Starting with the "Center Guide" part, I plugged it into the pre-cut hole from the front side, which left a 1 3/8" circle covering the 30mm hole. I then used an xacto knife to cut the vinyl around the rim of the printed guide and removed the thin piece of vinyl. I took the "Center Guide" part out, and used masking tape to cover over the exposed cabinet where I cut the vinyl. The masking tape was just there to help prevent the drill bit from catching the edge of the vinyl and tearing it. I then placed the Center Guide back into the hole, but from the back side, leaving a little bit of the 3d printed part sticking out of the front of the 30mm hole. This piece sticking out of the hole is what I used to align the jig. I placed the 1 3/8" forstner drill bit inside the jig, then screwed the nut on most of the way, but leaving enough room for the tiny Jig Guide pieces. I placed those in and screwed the nut over top of them. The Jig Guide pieces extend into the jig to form a small brace around a 30mm circle. Perfectly sized to fit over the Center Guide piece currently protruding from the face of the 30mm hole. I placed the jig over the center guide, then used some clamps to clamp it into place. Then I removed the Jig Nut and Jig Guide pieces and also removed the Center Guide. At that point the jig was ready to go. I just had to attach the drill to the forstner bit and start drilling. I sized the jig to match my forstner bit as close as possible. It's designed to stop at exactly 3/8" depth if the bit is correctly placed all the way inside the chuck. I used the 1 3/8" bit from the 14 piece Irwin Marples Forstner bit set. I love these forstner bits. This is a *lot* of effort for such a simple task. A $40 drill guide from Amazon will probably do the job better, and with a lot less frustration. With all of the sanding for the Jig Nut, and how fiddly it was to line up the Jig Guide pieces, on top of the modeling/printing (and re-printing), I probably wasted way more than $40 of time on this, and it's only useful for this one task. Just get a multipurpose drill guide and save yourself some time. Really.

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