As for those holes in the side? They are threaded as 5/16" by 18. Common enough size. Picked up a couple bolts at HD, had a couple washers on hand. Molested a bit of walnut scrap with a #78 rebate plane to add a rebate .
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But it needs to be a hair deeper, to reach over to the mouth. Rounded the ends, and an oil finish
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Rounded the ends to keep my fingers from getting caught.
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Seems to work decently enough. Might get even better after the fine tuning?
HD did not have any Thumb screws, so these cap bolts will have to do, for now. Takes a 1/4" Allen wrench.
We'll see how it works out....
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Takes a bit of getting used to, too.