Below is a tutorial that should answer all your questions.....
http://www.smokingmeatforums.com/t/...others-ready-to-use-rev5-6-19-15#post_1264161
here is an excerpt that describes the RF plate......
When you open the "Circle Calculator" link, Click on the "bullet" to the left of Radius & Segment Height ED....
Circle Calculator
Click on the 2 variables you know
......Radius and Central Angle...........................Radius & Chord AB
[X] Radius & Segment Height ED.....................Radius & Apothem OE
......................................................Radius & Arc AB
......Chord AB & Segment Height ED................Chord AB & Apothem OE
......Segment Height ED & Apothem OE...........Chord AB & Arc AB
You should have opened the circle calculator and a bunch of boxes will appear below..
and a box called [CALCULATE]..
Enter the radius in the box so marked.... If you tank is 24" OD, and has a 3/8" thick steel wall, the ID of the tank 23.25".... the radius is 11.625"..... these numbers need to be accurate if you want stuff to fit... ALSO, take into account the thickness of the FB steel when cutting out the tank...
Enter a guess for the Segment Height ED... I'd start with 6.0
Click on [CALCULATE]....
The other boxes will fill with numbers....
The [Segment Area] box is what you area going to compare with the FB/CC opening in square inches...
If the FB/CC opening number is smaller, change the number in the Segment Height ED box to 5.... continue changing that number until the [Segment Area] matches the FB/CC number.....
Now look at the colored circles above....
Segment height ED is how tall the green area is and corresponds to the area to be cut out.....
Also, [Chord AB] corresponds to the width of the RF plate... NOTE... for ease in fitment, the FB should be at least as wide as the RF plate..
