Author Topic: Grommet Job on 1979 Rhodes Mark I Stage 73...  (Read 158 times)

Offline sean

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Grommet Job on 1979 Rhodes Mark I Stage 73...
« on: February 10, 2018, 03:42:55 PM »
I recently replaced the grommets on my 73-key 1979 Rhodes Mark I Stage piano.  I used the original screws and washers.  The new grommets I used are McMaster-Carr 9305K21.

I am very happy with the results.  The new grommets fit tighter, and are softer than the old shrunken grommets that they replaced.  The piano sounds more lush, and has more sustain.

I like the McMaster-Carr grommets because they cost nine bucks per 73-key piano.  If you don't buy in bulk, and you just buy for only one piano, then the $6.19 shipping cost makes it cost $14.32 per piano.  Still pretty cheap.  These are the only grommets for which you can find the exact dimensions before you purchase. 




The McMaster-Carr 9305K21 grommets are made of SBR Rubber (Styrene Butadiene synthetic rubber) - same kind of synthetic rubber that goes into car and truck tires.  They are listed as being medium-hard, durometer 60 Shore A.  I have no idea how that compares to the grommets of the 1970s nor other grommets from our friendly specialty suppliers.  The specs and dimensions of the 9305K21 grommets are clearly shown on the McMaster-Carr website, so you know exactly what you are getting.  The Rhodes-specialty suppliers (VintageVibe, Retrolinear, Ken Rich, cvkeyboards, and Avion Studios, etc.) don't show any product dimensions, hardness spec, nor material type.

The 9305K21 grommets have an inside diameter of 0.125".  The original screws on my 1979 piano have a shoulder diameter of 0.142", so they fit tight inside the 9305K21 grommets.  If you have an older piano, your screws might have a larger diameter, so the fit might not work out very well.  The fit on my 1979 screws was tight enough to be annoyingly difficult to insert the screw into the grommet.  The fit of the grommet into the tone bar and spring is perfect, nice and snug. 

The McMaster-Carr 9305K21 grommets are not beautifully molded, nor rounded and tapered.  There were some that had a lot of mold flashing that needed to be ripped away, but there were no rejects.  I don't think that a rounded top or tapered stem would make a significant difference in installation nor sound.  I would definitely choose these grommets again.  There are at least two Rhodes-specialty suppliers that sell grommets that are indistinguishable from the McMaster-Carr grommets.  I assume that they are identical, and sourced from McMaster-Carr.

Most of the Rhodes specialty retailers sell grommets that have a rounded top edge and a tapered bottom rim.  I believe that the original Rhodes grommets had this shape too.  They look something like this:




It took me a few days to get the grommet job done, and it was not much fun.  I worked ten tonebars at a time, but it still took me a more than an hour to get ten tonebars done.  The wax is a small annoyance, and it is nice to have that all vacuumed away and buffed off the tonebars and springs.  What a mess that stuff is.  The biggest problem is bent screws.  Not many are still straight.  I wonder if the original builders installed the tonebars, adjusted the intonation, and then hammered any tilted or twisted tonebars until they looked perfectly straight for the quality control or acceptance inspectors.  The original screws are pretty soft and irregular.  I straightened the ones that were horribly bent with a few hammer taps.  This is not a very precise method, but it made the worst screws less hateful.

It is no wonder that Vintage Vibe decided to use modern screws and matches their grommets to those screws.  This would save a lot of time in maintenance, and provide a much higher-quality mounting system.

Sean