from Warren Fisher: << All the vertical hammers I've replaced so far have had 5-10 degrees of downward angle (rake) at rest to compensate for flexing of the shank on a hard blow. This means at normal play they don't strike at exactly 90 degrees. The most important concern is the correct strike point on the string, because that causes the most effective and powerful beginning of the vibration pattern and harmonic generation for that string! Just a tiny bit off on either side will make the note sound muddy. I'm sure you've noticed that test blows while tuning don't sound as clear as when you're just playing the note. It's because the hammer is striking above the strike point! >> Warren - My understanding is that the rake on vertical hammers is so that the shank will be behind vertical when the hammer strikes the string, which causes the weight of the butt/hammer assembly to be centered farther behind the flange pin, which makes the hammer more willing to "fall" back, aiding its return. I also suspect (without denying that the strike point changes a little on a hard blow) that the muddy test blows could be caused by sideways motion of the hammer, causing it to catch the edge of the grooves. If I'm right, you will hear this change of tone in the tenor and low treble, where a 1 mm change in strike point doesn't make an appreciable difference. I'll also bet you'll find this effect less evident on ungrooved hammers. Bob Davis
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