Category Archives: 32766

Key Bushings

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The plastic keys on my last piano required nothing more than to be cleaned before being reinstalled. When I began working on this, my first piano with wooden keys, I was eager to explore the workings of its more standard action assembly. I may have been too eager as I probably ended up investing more time in the keys than in all other components combined.

The keys employ felt at several contact points to make their interaction with other parts smoother and quieter. Each key mounts in the piano by two narrow metal guide pins which are pressed into what appears to be oak or ash rails on the key frame. The openings in the keys through which the pins pass is padded with felt bushings. These bushings will eventually wear out allowing the key to move too much from side to side and giving the piano a very sloppy feel. Since the front bushings bear the brunt of abuse from zealous players, their guide pins are specially shaped – more oval than round. When the pins are rotated, their thickness changes relative to the keys’ bushings. In this way, a bushing replacement job can be forestalled until the material’s condition is critical and can no longer be compensated for by turning pins.

The balance guide pins at the keys’ fulcrum are round and offer no mechanism for adjustment. The keys’ balance bushings can be adjusted slightly by manipulating the wood they’re glued to but once the felt has worn down very far, it must be replaced to restore the piano’s original feel. In retrospect, and particularly after having since seen key bushings that were truly worn beyond their usefulness, the bushings on this piano did not need to be replaced. I was so interested in digging into some “real” piano repair work that I convinced myself that the job was necessary. I could have just turned the front pins a little and been done with it but it was a learning experience nonetheless.

Before new bushings could be installed, the old ones had to come out. Steam is typically used to soften the glue under piano bushing felt. I had also read naphtha would work on the Rhodes felts. For me it seemed no amount of solvent or time was enough to convince the glue to let go so I resorted to acetone. A big problem with acetone is that it quickly reacts with the plastic of the key caps. An errant drop will instantly damage the surface of the caps… but boy did it make short work of the glue.

Although it worked easily on the balance bushings, the acetone seemed to have no effect on the front ones. Coincidentally, another member of The Electric Piano Forum happened to have just posted the same experience during his first key bushing job. He reported that steam was an effective means of removal. I don’t have any equipment for working with steam but my friend Matt showed me a simple solution often used to steam out small dents on solid-body guitars. With a soldering iron and a wet rag, I was able to press steam directly into the felt. After about thirty seconds of this treatment, the felt fell off the wood taking all of its glue with it. Since the steam was so much safer, did not give off volatile fumes and clearly outperformed the acetone, I used it for all of the remaining bushings.

Installing new bushings is very reminiscent of the game Operation. Inserting the proper amount of felt and securing it in place for the glue to dry requires special tools and a degree of finesse. The felt is supplied in a continuous roll. The common approach is to apply glue to the ends of two separate lengths of felt, insert and secure them at the proper depth, then trim off the excess either immediately or after the glue dries. The felt can be held in place by a variety of blocks, cauls or clips such as the set I purchased from Vintage Vibe. Before I learned this method, I had already become comfortable with my own technique and since it seemed to yield satisfactory results, I saw no reason to change.

Rather than trim the pieces after they were set, I precut the felt. After covering one side of the pieces with glue, I maneuvered them into position perched at the edge of the hole in the key. When the metal clip was inserted in between them, they rode down into the hole and positioned themselves perfectly. Although at first I cut my felt a little large and had to trim them down, I soon began cutting them short enough that they required no further work after their glue dried.

When the keys were finally reinstalled, most of them gripped their guide pins far too tightly. I think that between the steam causing the wood to swell and having used a one-size-fits-all gluing clip, I was left with more easing to be done than would otherwise have been necessary. To open the gap between the bushings I used a small pair of pliers to slightly compress the wood under the felt. A putty knife worked well as an outside clamping caul for this operation.

Cabinet Preparation

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At first glance, the case for this 1973 piano didn’t appear to be in very bad shape. Some of the latches had been replaced and a few extras were added. A couple of the hinge screws had been replaced with nuts and bolts. I expected this to add up to a few extra holes that would need to be drilled and plugged like with the last case. When the old Tolex was removed, the truth of the matter was revealed… and it wasn’t pretty.

The reason new latches were installed in non-standard locations was because the wood under the original latches was in no shape to support any hardware. On one side, the wood had come completely apart and was only being held in place by the Tolex. The wood under the hinge screws was still in place but was also split and would no longer hold wood screws. A couple of other corners were also missing significant amounts of wood and the front edge of the lower half had a perfectly shaped semicircle missing where a knot had come loose and disappeared.

The case on this older piano was quite different than that of the 1981 I had previously worked on. An obvious difference is in the angled sides. On older models, the angle changes towards the front of the case so that the front edge is horizontal. The rear edge doesn’t get the same treatment and it mirrors the angle of the sides. At some point in a later year, this feature was removed from the case design and the same angle continues around the entire case. I was interested to see the obvious evidence of the saw blade that was used to cut the angled sides. Rather than concern themselves with making a squared cut, the builders just overran the saw then cleaned up the kerf with some filler.

Another difference was immediately apparent when the Tolex was first peeled back. Whereas the case for the 1981 Mk II was made entirely from 3/4″ plywood, the face of the top on this piano was made from something like Masonite. And although it should have been apparent by the splitting at the hinges and latches, I didn’t realize until I sanded down to bare wood that the sides of the case were solid pine. The only plywood in the entire case was the face of the lower half which needs to be sturdy enough to support the the piano perched atop its four legs.

Unfortunately, the plywood was not in great shape. The first clue to its condition was the gap where the the edge met the side board. The plywood seemed to be made up of only three quarter-inch thick plies and two of them had by this time parted ways. I was able to tap the wood, listening for the hollow thud to map out the extent of the delamination. I next drilled holes through the single loose ply, stopping short of the underlying layers to provide access to the cavity in between. I added a little rubber washer to a needle-less syringe so that I could force glue into the holes. After pumping in a generous amount of glue, I drilled the rest of the way through the wood and clamped the plies together with bolts and fender washers.

The gap in the front edge where the knot used to be was to be filled with Bondo but given the shape of the void and the smooth face of the underlying wood, I was concerned about the filler’s ability to stay put. To give the Bondo something to hold onto, I first drilled little pilot holes in the wood then installed finish nails that had been cut down below the surface of the case. I think the finished product will last for a while.

How to deal with the split wood under the hardware mounting points was a bit of a problem. Even if I could just glue the wood back together, I feel the design was flawed from the start since a great deal of stress is placed on the wood at a point where it’s quite weak. Replacing the sides with new plywood would have been a good option but I really prefer to keep as much of the original piano intact as possible. I decided to replace just the problem areas with patches made from plywood. The plywood would provide good anchors for the hardware screws but the rest would remain vintage wood.

First, a notch large enough to eliminate all of the split wood was cut out of the edge of the case. Then, a plywood patch about an 1/8″ larger in both dimensions was made. A groove was cut in three edges of the patch using the table saw and a tongue was created in the case by routing in an 1/8″ on both sides. After a little adjusting for fit, the whole thing was slathered in wood glue and clamped overnight. A little Bondo cleaned up my sloppy cabinetry and made for a seamless finish.

Just about every corner was coming loose but between more glue and some long clamps, they were all locked back together. Bondo put the finishing touches on the corners and this case is now ready for its Tolex.

Plating

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I spent too long debating how best to deal with the harp frame and tone bars. These internal steel parts were originally zinc plated and most have not held up well to the passage of time. Zinc protects the steel by being a ‘sacrificial metal’. Instead of preventing corrosion, the zinc simply corrodes preferentially to the underlying steel. When the zinc corrodes, a white powdery substance is left behind in its place. Although even this powdery oxidation still provides some protection, once the zinc has been converted, the steel is largely left to the mercy of the elements and soon begins to rust and pit.

My debate over these parts centered on whether or not I was going to outsource their restoration. There are a few sources for home electroplating kits and I gave very serious consideration to the product offered by Caswell Inc. which promised everything I’d need to go from bare metal to a professional-quality finish. This appealed to me for a couple of reasons. Ideally, I’d like to perform as much of the pianos’ restoration work as possible myself. Also, the plating kit would likely pay for itself after just a few pianos by saving the cost of using a third party for this service.

Ultimately, I was scared off from the home plating option by the apparent complexity and scope of the job. Even as a kit designed for amateur use, this is no simple operation. It involves multiple stages each requiring its own combination of potentially dangerous chemicals, tricky operating procedures and some degree of luck. The steep learning curve aside, a plating setup – especially one that could accommodate the large harp frames – would occupy a significant amount of real estate in my small shop.

Among the plating businesses I looked at, it seemed standard to divide plating jobs into two general groups: drum and rack. Smaller parts (up to maybe twelve inches long) can be plated using a drum that rotates like a rock polisher. The parts tumble around inside until eventually all surfaces are consistently finished. Larger pieces must be hung from a rack and dipped individually in the plating bath. For my parts, I needed to find a plater that could provide both drum and rack services.

Prior to sending the parts away, they needed to be cleaned and polished. Zinc plating is extremely thin and does nothing to compensate for imperfections in the surface of the base metal. I tried using a blast cabinet to prepare the parts but even using a fine blasting medium, the result was a satin finish that was too far from the original look. Instead, the bulk of the cleaning was done with wire wheels, both on the bench grinder and chucked into a hand drill. After achieving an acceptable finish with a wheel, a final polishing was done with some 400 grit polishing papers.

In the old days, after applying zinc plating, parts would often go through a ‘chromate conversion‘ process that added a protective layer to the zinc. This is what gave the Rhodes parts their iridescent yellow coloring. Although you can still have zinc chromate plating done, it’s more recently been heavily regulated due to reasons discussed in the movie Erin Brokovich. Replacements for the chromate process have been developed but they offer little or none of the protection provided by the old, more toxic process. Although the plater I used offered the old stuff, I chose to go with his replacement option. The resulting color looks pretty good but, at least on the tone bars, could not stand up to even the slightest abrasion.

1973 Seventy Three Mk I

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When referring to these pianos, most people say “Fender Rhodes” even though the Fender name only appeared on units for 9 of the 22 years they were in production. According to the Fender Rhodes Supersite, there were no changes to the piano’s construction that coincided with the dropping of the Fender name. So for all practical purposes, there is no difference between a Rhodes and a Fender Rhodes. Regardless, I wanted one with badges that included “Fender”.

Once again, eBay came through for me and I paid what was probably too much for a 1973 Seventy Three Mk I. The seller had acquired it at an auction at a university where it had been in storage for many years. Like the last eBay purchase, this one included all components. This time, it even included the legs and sustain pedal. The only things missing are a few pieces of case hardware, the knob for the leg braces and the vinyl leg bag.

In 1973, Rhodes were built with wooden harp supports instead of aluminum. The hammers were “hybrid”, made up of both plastic and wood. What I don’t know is whether the damper felts are extremely misshapen or were designed to partly wrap around the tine like on an acoustic piano. The pickups on this one were wrapped with a cool green wire. I’ve had to re-wrap six pickups on my 54 so I was surprised to find that this one, like the last 73, seemed to have all of its pickups intact.

The case and Tolex have a few road scars and had been outfitted with some aftermarket latches. I don’t even know how double-hung window locks could have held the case closed. A few tone bar grommets have blown out and some hammer tips are missing but other than that, the interior is in pristine condition.