From 20 years ago. Just get a piece of aluminum angle and start shaping it.
Here's how it's done in the RV-8 - from DWG 65. Hope I'm not breaking any rules by uploading this.
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True - the slot assumes a very thin seatbelt attachment. If I were doing it again, I'd make it a bit thicker.... This is one of those cases where it would help to have/or know the hardware you'd be utilizing in the future. ...
Thanks to all for replying.
Yours looks much like the instructions for the F1 but there's no details on the part/bracket itself. I will most definitely utilize the available strength of the long's. Was that a 3/16 angle you used?