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I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces.

The jig makes a hole like this at a 15 degree angle.

The 720 works like this:

I'm trying to calculate the length of the drill bit which I can set with a stop. The 720 has stops included for common wood, but I like to be exact and I need to understand the geometry of how the 720 works. I zeroed out an angle meter and found that the case is exactly 57 degrees.

But! I wanted to make sure that the drilling jig block moved at 57 degrees, so I used my caliper to measure the board thickness block at the bottom and the top. That gave me these measurements.

Per this geometry:

So $\theta = 45 \deg$ which is intuitive for a jig like this. However, the case seems mounted to match the $57 \deg $ that I measured. I also measured the picture in photoshop and got the $57 \deg $ as well.

I'm confused with how these could be different. Obviously the case doesn't have to match the internals, but $12 \deg$ is a big difference. I'm curious if anyone has looked at this.

$d$ is the measurement from the base to the bottom of the moving block. $s$ is the distance between the back base and the front of the moving block. (I would love better language for these pieces too!)

At the bottom:

I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces.

The jig makes a hole like this at a 15 degree angle.

The 720 works like this:

I'm trying to calculate the length of the drill bit which I can set with a stop. The 720 has stops included for common wood, but I like to be exact and I need to understand the geometry of how the 720 works. I zeroed out an angle meter and found that the case is 57 degrees, but I took some measurements at the top and bottom and through taking the tangent, figured out that the sliding block moves closer to 58 degrees.

But! I wanted to make sure that the drilling jig block moved at 57 degrees, so I used my caliper to measure the board thickness block at the bottom and the top. That gave me these measurements.

Per this geometry:

From this I'm trying to find $D$ the length of the shaft of the pilot screw given $t_{\text{min}}$, the minimum thickness, $t_b$ the thickness of the board for pocket holes, $t_T$ the thickness of the board you are screwing into, $\theta$, the angle of the jig, and $s$, the length of the shaft of the screw.

I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces.

The jig makes a hole like this at a 15 degree angle.

The 720 works like this:

I'm trying to calculate the length of the drill bit which I can set with a stop. The 720 has stops included for common wood, but I like to be exact and I need to understand the geometry of how the 720 works. I zeroed out an angle meter and found that the case is exactly 57 degrees.

But! I wanted to make sure that the drilling jig block moved at 57 degrees, so I used my caliper to measure the board thickness block at the bottom and the top. That gave me these measurements.

Per this geometry:

So $\theta = 45 \deg$ which is intuitive for a jig like this. However, the case seems mounted to match the $57 \deg $ that I measured. I also measured the picture in photoshop and got the $57 \deg $ as well.

I'm confused with how these could be different. Obviously the case doesn't have to match the internals, but $12 \deg$ is a big difference. I'm curious if anyone has looked at this.

$d$ is the measurement from the base to the bottom of the moving block. $s$ is the distance between the back base and the front of the moving block. (I would love better language for these pieces too!)

I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces.

The jig makes a hole like this at a 15 degree angle.

The 720 works like this:

I'm trying to calculate the length of the drill bit which I can set with a stop. The 720 has stops included for common wood, but I like to be exact and I need to understand the geometry of how the 720 works. I zeroed out an angle meter and found that the case is exactly 57 degrees.

But! I wanted to make sure that the drilling jig block moved at 57 degrees, so I used my caliper to measure the board thickness block at the bottom and the top. That gave me these measurements.

Per this geometry:

So $\theta = 45 \deg$ which is intuitive for a jig like this. However, the case seems mounted to match the $57 \deg $ that I measured. I also measured the picture in photoshop and got the $57 \deg $ as well.

I'm confused with how these could be different. Obviously the case doesn't have to match the internals, but $12 \deg$ is a big difference. I'm curious if anyone has looked at this.

$d$ is the measurement from the base to the bottom of the moving block. $s$ is the distance between the back base and the front of the moving block. (I would love better language for these pieces too!)

At the bottom:

I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces.

The jig makes a hole like this at a 15 degree angle.

The 720 works like this:

I'm trying to calculate the length of the drill bit which I can set with a stop. The 720 has stops included for common wood, but I like to be exact and I need to understand the geometry of how the 720 works. I zeroed out an angle meter and found that the case is exactly 57 degrees.

But! I wanted to make sure that the drilling jig block moved at 57 degrees, so I used my caliper to measure the board thickness block at the bottom and the top. That gave me these measurements.

Per this geometry:

So $\theta = 45 \deg$ which is intuitive for a jig like this. However, the case seems mounted to match the $57 \deg $ that I measured. I also measured the picture in photoshop and got the $57 \deg $ as well.

I'm confused with how these could be different. Obviously the case doesn't have to match the internals, but $12 \deg$ is a big difference. I'm curious if anyone has looked at this.

I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces.

The jig makes a hole like this at a 15 degree angle.

The 720 works like this:

I'm trying to calculate the length of the drill bit which I can set with a stop. The 720 has stops included for common wood, but I like to be exact and I need to understand the geometry of how the 720 works. I zeroed out an angle meter and found that the case is exactly 57 degrees.

But! I wanted to make sure that the drilling jig block moved at 57 degrees, so I used my caliper to measure the board thickness block at the bottom and the top. That gave me these measurements.

Per this geometry:

So $\theta = 45 \deg$ which is intuitive for a jig like this. However, the case seems mounted to match the $57 \deg $ that I measured. I also measured the picture in photoshop and got the $57 \deg $ as well.

I'm confused with how these could be different. Obviously the case doesn't have to match the internals, but $12 \deg$ is a big difference. I'm curious if anyone has looked at this.

$d$ is the measurement from the base to the bottom of the moving block. $s$ is the distance between the back base and the front of the moving block. (I would love better language for these pieces too!)