I have a problem. I have to attach a tune-o-matic bridge on my guitar but i don't know in which angle this has to be. I have done some research in the internet but i found nothing usable. Is there somebeody who could help me with this?
As with all bridges, the idea is to make sure the scale length for each string is correct. In an ideal world they would all be the same length, but string thicknesses and tensions actually mean intonation is not right if you do that, hence tune-o-matics and others have adjustment.
The good thing about a tune-o-matic is that you don't need to be 100% accurate in your positioning but a few websites suggest that if you set your initial position with all adjusters right at the front of their movement at the 25" mark (for a 25" scale guitar) you should keep the treble mounting post where it is and rotate the bass end about 2-3 degrees away from the nut - effectively lengthening the bass string by about 2-3mm. This isn't absolutely necessary, but does give you the extra intonation room in the direction you'll probably need it.
This pic from projectelectricguitar.com shows what I mean: