Good to see a home brew dremmel block!, always!...
I'd put four allen bolts in there to hold it together as well though, about 1CM in from the mount holes, but it's your block
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Nice one!, have you thought about using a 'slitting saw' blade on your Dremmel?, those are real thin (less than 1mm) and have a small but consistant diametre, there's some pics and prices halfway through BB2K's 'RADIUS' thread, somewhere!
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PM him for details maybe?...