1.Set the pitch of the middle c from a tuning fork. Find the spot of the beatless by turning the tuning pin. When you turn the tuning hammer, you should do it as slite as you can.

2.Tune f below middle c to be pure and beatless.

3.Tune #a above f to be pure.

4.Tune ＃d above #a,

5.#g below #d,

6.＃c above #g,

7.and ＃f below #c to be pure.

8.Return to middle c.

9.Tune g below c to be wide thirds. "Wide thirds" is three beats per second outside pure.

10.Tune d above g to be narrow seconds. "Narrow seconds" is two beats per second outside pure.

11.Tune a below d to be wide thirds.

12.Tune e above a to be pure.

13.Tune b below e to be pure.

Middle c and e should be three beats/second. If not, you should check the process.

【Impossible?】

Do you mistake wide for narrow or narrow for wide？
You may use free smartphone apps like a frequency generator. Be match with the frequency by beats. Refer to the following.

Now you have done. From f, tune upward chromatically by octaves. Then downward from e. Finally, tune another choir. This time you tune them all to be pure and beatless, of course.

【You don't have any c=494Hz tuning fork?】

If you have only modern pitched a fork, you begin with #a. Then down to f, up to c, and return #a. Then you tune as stated above.

SUMMARY

1.c↓ 2.f(p)↑ 3.＃a(p)↑ 4.＃d(p)↓ 5.＃g(p)↑ 6.＃c(p)↓ 7.＃f(p)

8.c↓ 9.g(ｗ3)↑ 10.d(n2)↓ 11.a(w3)↑ 12.e(p)↓ 13.b(p)

[ Check: c ↑ e(w3) ]

* p＝pure w＝wide n＝narrow