For the part in Prob. 630, recommend a fillet radius r that will cause the fatigue factor

Question:

For the part in Prob. 6€“30, recommend a fillet radius r that will cause the fatigue factor of safety to be the same at the hole and at the fillet.
In Prob. 6€“30, The figure shows the free-body diagram of a connecting-link portion having stress concentration at three sections. The dimensions are r = 0.25 in, d = 0.40 in, h = 0.50 in, w1 = 3.50 in, and w2 = 3.0 in. The forces F fluctuate between a tension of 5 kip and a compression of 16 kip.