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Since the OP has not been back, we don't have any idea what precision is needed, the number of holes, nor what tooling is available. But if it's not done yet, there's a good bet it's not due to lack of suggestions.
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Back in the old days, I would dig out my 3/8" hand slotted shaft. Chuck it up in a drill motor, wrap 1" wide emery cloth around the shaft, hold the cloth tight until it was in the hole, and hit the switch, turning that emery cloth around in the hole, widening it out.
Steve
Mo.
I miss the days of using my dinghy with a girlfriend too. Zack Butler-4/18/24
The Revos apparently are designed to clamp railroad ties and pull together horrifically prepared joints
WaterlooMark 02/9/2020
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hole saws cut a little big, use a 3/4. Learned that one in engineering school.
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(04-11-2018, 08:42 AM)Engineer Wrote: I am trying to drill holes in 3/4 inch plywood that are slightly larger than 3/4 inch. I start with a 3/4 inch Forstner bit, but my holes need to be .78 inch in diameter. How can I do that?
Interesting problem I had about 5 years ago! A 'late at night' project, use what you have solution. I made a custom step bit from a spade bit. It worked like a charm! I gave the tip to Colin Knecht, Woodworking Web - he included it in a recent video. Find the tip about 1-1/2 minutes into the video.
Workshop Hacks Part 3
-Don
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The only hole I see here is the one the original OP has fallen into.