Pilot hole for 5/16" lag screw in very hard wood


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Old 03-26-08, 03:30 PM
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Question Pilot hole for 5/16" lag screw in very hard wood

Need to drill a pilot hole for a 6" X 5/16" galvenized lag screw into teak. It is to mount a chrome end piece - actually a 7/8" X 1/2 inch chrome socket on a flag pole. The screw will run "down grain" so I am concerned I get adequate bite, but do not want to split the wood.

What size bit?
 
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Old 03-26-08, 04:10 PM
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6" into teak end grain, you need very little bite. Those large threads will not shear the fibres, but rather pinch them, which is good.

The roughness of a galvanized lag screw adds to its diameter, so I think your best bet is to take it to the bit aisle and select whatever bit is very slightly smaller than the screw. I would be prepared to file the screw threads if the fit seems too tight.
 
 

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