Smithy upgrade

formula is roughly base value x (1.015 ^ (smithy level)) based on Travian Answers. So if I have a clubswinger and my smithy upgrades are at lvl 1, then it would be 40 x (1.015^1) = 40.6 attack power. Based on this, you can get an additional 34.69% bonus when you have your upgrades at lvl 20.

0 40.0021
1 40.5800
2 41.1620
3 41.7480
4 42.3381
5 42.9324
6 43.5308
7 44.1334
8 44.7403
9 45.3514
10 45.9667
11 46.5864
12 47.2104
13 47.8388
14 48.4715
15 49.1087
16 49.7504
17 50.3965
18 51.0472
19 51.7025
20 52.3623

here is an example for clubswinger,calculated on t.4 version,normal speed.i used that forumula from the top of this post...

regards,
Mario