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How to make perfect holes in spar?

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Jul 18, 2007
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I made most of the spar drillings for hinges 1/4",flying wires pins .75"and plates 1/4",butt fittings plates 1/4" 3/8" 5/16",ect...They were done on a drilling press before ribs assy and gluing;all were perfect.Then I have glued all plywood plates on one side of each spars,and after drying,I drilled the plates with a small drill,helped by the holes already done in the spars.Then glued the plywood plates on the other side of the spars,and drilled through.But now is the problem;the holes are not straight,not perpendicular to the spars anymore,just some small angles!!!I made some cylindrical parts with spruce that I have glued with T88 in each holes.

So,here is the big question..how to make perfect drills to get holes perpendicular to the spars.



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