Firewall measurement

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Joe Parish
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Firewall measurement

Post by Joe Parish »

At the point of drilling the firewall to the side skin. When I measure the 5/8 inch distance called out in the plans, firewall 5/8" back from the forward edge of the 970 side skin. I used a square and measured the 5/8 right along the edge of the firewall. Once I had that all set I used a thick piece of angle and set it across the front of the firewall and took some measurements. I was getting an average of 2 to 3 32nds over the 5/8 I am trying to achieve. The question is am I being to critical and should I go back to getting the 5/8 measurement at the edge of the firewall and call it good? I do have a hole drilled on each side on the bottom of the firewall.
When I went back and got the measurement set as close as I could get in the middle area of the firewall, the measurement out at the edge seems to be one or two 32nds shy. Hope that makes sense. Thanks for the input.
Joe
N525XC reserved
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bruceh
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Post by bruceh »

The flanges of the firewall and the side skin forward edges don't necessarily line up perfectly. I would draw a line down the middle of the firewall flanges with a Sharpie, then put the side skins over it, and make sure that lines up with the prepunched holes in the side skins. Go slow when drilling the stainless steel and use lots of lube or you will burn up your drill bits.

Sort of see how it lines up on mine here.
Image

Bottom skin and firewall flanges here.
Image
Bruce Hill
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Joe Parish
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Location: Sioux Falls SD

Post by Joe Parish »

Thanks for the input Bruce. Much appreciated.
Joe
N525XC reserved
Empennage done
wings done
Fuse in progress
RV-9A

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