Dear Peter,A rake angle of 93 to 94 degrees is normal in European pianos. For Renner Germany it is standard. Matthias Stöckle (Renner Germany) prefers 93°. But you can also choose 90°. With Abel it is the same. https://www.abel-pianoparts.de/index.php?index=1&lng=en&menuid=65&ordner=shop-40I had a discussion with Joachim Leonardy of Jahn about this. He said that it does not matter what you do, as long as the the hammer hits the string in an angle of 90 ° . In the case of 90° your shank has to be parallel with the string. And from that you can deduct the bore length. When the rake angle is 93° the bore length is about 3 mm shorter. You can calculate the bore length.In some cases the 93° is a way to keep the hammer from hitting the frame or the belly bar. This can happen in the high treble in old Bechstein grands.