Bought these metal female threaded M10 stainless bolts on Amazon Link to purchase here
At Hometown Ace Bought M10 Stainless Bolt and Lock Washer.
Started pilot hole by lining up the bolt on the vent and marking the middle with a much smaller drill bit. Once the smaller bit was through went through with a 3/8ths which was a perfect fit. then just put everything through as shown and tightened.
Done-
This mod can be done on any bare Weber vent.
Northeast BBQ 