# How do I calculate screw lengths for Kreg Jig versus regular screws?

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Joined: 2011-02-12 21:43
How do I calculate screw lengths for Kreg Jig versus regular screws?

How do I calculate screw lengths for Kreg Jig versus regular screws? I mean, if the screw goes in at an angle, then it doesn't need to be 1 1/4" long if that's what I would otherwise be using to drill straight in, right? It should be shorter, I think. So, how do I know how to adjust the sizes accordingly? I'm trying to make my plans for the sewing box and am stumped by this. Thanks!

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Joined: 2011-01-26 17:28
Don't worry too much

My off the cuff guess is that a pocket hole is roughly 10 degrees off from being straight in. At that angle, the depth of penetration would be about 98% of the depth if you were going straight in.

If you want to get really precise, the actual depth is:

x cos(a)

Where x is the length of the screw, and a is the angle the screw is going in at (and if you don't remember your algebra, multiplication is the implied operation).