This is an intriguing question that I rarely encounter. The groove of the single pin heavy duty clamp should fit the flange of the tri-clamp connection snugly when properly secured. For a 2" clamp, the outer diameter is 2.516" and the inner diameter is 1.870". Subtracting these gives 0.646", but this accounts for both flanges combined. Dividing by 2 gives a height of 0.323" for each flange and the groove. This principle applies to other sizes, with the groove size increasing with flange size. Please reach out if you have further questions.