Author Topic: Hammer cam to key pedestal alignment- is my harp lopsided?  (Read 99 times)

Offline Lydmariemusic

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Hey everyone, I'm new to the forum and new to the Fender Rhodes restoration world. So, I'm installing the miracle mod kit on my 73 key 1973 Mark 1 Fender Rhodes. I just removed all the old felts and was getting ready to figure out bump placement when I realized the back of the key pedestal on my low E does not line up with the back of the hammer cam. The hammer cam hangs over the edge about 1/8". This means, in order for the hammer cam to be flat against the key pedestal I need to push the key into after touch.

Its seems that the harp is slightly lopsided because on high E the alignment is perfect. Can I move the angle of the harp to correct this 1/8 inch tilt? Does it matter even? Will it affect tone or the way the bump functions? Thanks in advance for your help and I'm excited to be here learning more about my instrument!


Offline sean

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Re: Hammer cam to key pedestal alignment- is my harp lopsided?
« Reply #1 on: March 28, 2021, 04:59:22 PM »
Dear Lydia,

You can move the harp any way you want, but it won't change the relationship between the key pedestal and the hammer cam... you mean that you want to move the action rail.  This won't be fun.  You can pull the keyframe and action out of the piano, and then you can get to the screws that hold the action rail from the underside.  There might be some slop in the holes, but probably not.  To make a real correction, you can either enlarge the holes in the keyframe, or re-drill new holes an inch to either side.  This is not too hard to do because the 1973 piano has a wooden action rail.  Finding the right position is the hard part.  If there are shims between the keyframe and the action rail, mark their position before you remove them.

It should be obvious that moving the action rail forward or backward will affect the feel of the action.

Don't push your keys into "aftertouch" - all you are doing is trying to break the flanges on the hammer comb that hold the hammers in place, or break the bumps off the hammer that hold it into the hammer flange.

Now, to be honest, I don't think I understand what you are trying to describe.

On my dear departed 1973 Fender Rhodes, the hammer cams did not come close to the front edge of the key pedestals.  They didn't touch the bevelled front edge of the key pedestal.  I always wanted to move the action rail, so that the keysticks would have a bit more leverage on the hammers, and lighten the action, but I stupidly sold the piano.  I still regret it.  Anyway, it is not obvious which direction would result in lighter action:  move the action rail forward, and the keysticks have more mechanical advantage; but the contact place on the hammer cam is closer to the pivot.  Maybe moving the rail way back, so that the pedestals contact the hammer cams further from the pivot would work.   Alas... I never got to test this out.

Service Manual:
See chapter 2, 3, and 4:

It is especially painful that nowhere in the manual does it tell us any method for precisely locating the action rail in relation to the balance rail, nor any spec for the front-to-back alignment of the hammer cams with the key pedestals.

« Last Edit: March 28, 2021, 05:03:36 PM by sean »