Physics Metallurgy Frequencies

Project for my sister: Large wind chimes.

I quickly discovered I'm in over my head. I tried calculating the length for the notes (frequencies) I sought, and failed because there was no compensation for the type of metal pipe, the inside diameter, or the wall thickness at first. I did find a formula that compensated for inside diameter and wall thickness, as well as compensation for acoustic length versus physical length. However, nothing about material used.

I'm using black iron pipe, 6-5/8 inch inside diameter, wall thickness 3/16 inch. I'm trying to achieve three bells with frequencies of (C⁴ 261.63 Hz), (E⁴ 329.63 Hz), (G⁴ 392 Hz).

When I calculated and cut 3 different lengths, all three emit slightly above an A#⁴ at 470 Hz when struck. All instructions said to simply trim the pipe shorter to lower the frequency. If that were true, I should have yielded three different and distinct frequencies to begin with, even if off key.

I desperately and humbly beseech anyone with clear answers.