Avion Studios

Premium Parts for Piano, Rhodes and Wurlitzer

Hammer Tips - The Extra Long Version

Morgen SharpComment

Rubber...well specifically neoprene hammer tips came about as a result of the major redesign that Fender undertook from 1969-1970. The original CBS/Rhodes design used felt hammer tips which were one of many expensive aspects to production Fender hoped to change. (The other notables being MUCH lighter tone bars and slimmer tines. As well as cheaper damper felt.) I often complain about Fender's cost-cutting - but the fact is that Fender managed to make the Rhodes cheap enough that they sold around 250,000 in total and that's why so many people can still play them today.

So the engineers at Fender came up with some small neoprene tips. Neoprene is basically a chlorinated polyolefin which was first synthesized in 1930. The cool thing about chlorinating is that the chlorine molecules "fill the gaps" per se in the carbon structure of the polyolefin making it denser, more impact resistant and more resistant to ozone/atmosphere. To imitate the hardness of the original felt hammers (which became progressively harder as the felt was reduced from around the wooden core) they manufactured these new neoprene tips in a 4 (well sort of 5) hardnesses. At first Fender had colorants added to the tips to make them easy to identify. However it turned out that the dye made the tips degrade very quickly so they switched to spraying the extruded strips of neoprene before they were cut.

 Foreground original decaying red-dyed hammer tip.  Background are some square tips from an original Fender Parts Set. This set features short and tall red tips and large thinner wrapped wooden core tips. The original set also came with tines, grommets, springs and bridal straps. 

Foreground original decaying red-dyed hammer tip.  Background are some square tips from an original Fender Parts Set. This set features short and tall red tips and large thinner wrapped wooden core tips. The original set also came with tines, grommets, springs and bridal straps. 

Shape: Fender tried a number of shapes for these hammer tips. The first generation were sort of rounded like the felt hammers they were replacing. Then Fender switched to these square-type tips. They ultimately settled on a modified tear-drop style which was a little more precise about the striking surface and angle of attack. The neoprene tips, opposite of felt hammer, get slightly taller as they approach the treble section. The main concern being a clean let-off. The new thinner bass tines in particular move a great deal and a shorter hammer tip made it so they were less likely to touch the hammer tip after a strike. Whereas the treble end has very limited space where a sharper, taller triangle was necessary.

Hardness: We talk with a lot of techs and it's rare that I've talked to anyone that's perfectly happy with the voicing across a board. In an ideal world we would have twenty or thirty sizes and hardnesses of hammer tip, closer replicating the gradual attack of the original felt. But this is the real world people! So Fender decided 5 hardness levels was enough and extruded the softer 4 in long strips and then had them cut on an auto-feeder. The 5th, the wooden core will get it's own paragraph.

Hard-core: Because of the constraints of both space and hardness neoprene couldn't quite fit the bill for the highest treble end. However wood alone could damage the tines and also sound too different from the rest of the hammer tips. So a hybrid tip was born. Originally wrapped in the 3 layers of neoprene heat shrink, the design and materials also evolved along with the rest of the hammer tips. The size of the wooden core, the number of layers and the thickness of those layers has changed over the generations and re-designs. Fender had the advantage of large scale production but today these tips are made quite slowly by a handful of makers like Avion Studios. We lose a little less than 1/4 of the raw material during production - making these tips about 5X more expensive to produce than the others.

Special note - some customers have brought to our attention that some makers have used oak instead of maple. Oak is about 2/3 as hard as maple and also harder to mill properly.

 In the front you can see our lovely maple-core hammer tips which are double wrapped. In the rear are some very poor looking hammer tips we received from a different supplier which helped inspire us to make something better.

In the front you can see our lovely maple-core hammer tips which are double wrapped. In the rear are some very poor looking hammer tips we received from a different supplier which helped inspire us to make something better.

Conclusion: I hope this has been at least a bit useful or interesting. Mechanical keyboards often live in a really fun junction between engineering and imagination. These odd little hammer tips represent a creative solution to a unique problem. Like a lot of what Fender did, they aren't perfect but they are functional and relatively inexpensive. It was fun for us to get into the engineering and production aspect of this small piece to the Fender Rhodes puzzle. Please let us know if you have any questions. We're here to help!

Making a top/lid for your Fender Rhodes - DIY

Morgen SharpComment

We just finished building our dozenth top enclosure so I figured it was time to disseminate some of the tips and tricks we've picked up along the way.

 New over old. Rounded corners, screws mostly covered and routed for heavy duty butterfly fasteners.

New over old. Rounded corners, screws mostly covered and routed for heavy duty butterfly fasteners.

Warning: to do this project you will need some basic woodworking tools and general knowledge of how to use them.

For some reason, most likely either due to weight or faulty hardware, there seem to be a ton of Fender Rhodes out there missing their lids.

There are several styles of cases used throughout the years and we'll talk about a few of the differences but we are not going to go into any actual dimensions. The reason for this is because there is enough variation box to box that it's better to precisely measure your enclosure rather than rely on any figures we might give you. That said...

Step 1: Measurement

I'm omitting a common first step because it isn't totally necessary but we often disassemble the Rhodes, removing the feet and pulling the action from the base enclosure because more often than not we're doing a re-wrap. The advantage of this is you get a clean slate which is easier to measure and you can take the opportunity to repair any dings or gouges on the base.

Either way it's time to measure. The easiest way to mess up is using the rounded edges to get your measurements which can leave them short all the way around by anywhere from 1/32"-1/8". If you need a measurement from these dimensions it's often best to tack a flat piece sticking up over the edge so instead of hooking your measuring tape you can butt it up against the overhanging piece. Make sure the piece you tack on is tight against the side. Clamps will also work well.

If the corners are rounded you're measuring the bottom of the base, which is generally a good idea, but beware because often the manufacturing at the Fender factory was not that precise and the open sides may have slightly different dimensions than the bottom. Suffice to say it's best to get as many measurements as you can before you make any cuts.

Also note the angle of the various pieces. Typically around 15 degrees. Some cases level off in front of the keys giving a flat surface for the case in front of the keys while later models slant the key rail and back rail. This change makes for a less conventional key rail but an easier build. If you end up building both top and bottom this is an easier way to go.

Step 2: Materials

We typically use 3/4" project 5-ply and find that a single sheet is plenty. Project ply will have one sanded better quality side and one rougher side. Since you're most likely wrapping the case it isn't super important which side ends up facing where, we just find this plywood the most well suited that is commonly available. Wait to fill in any voids or knots until after assembly so you can address any chips or cracks from cutting and construction. 

We use the project ply for the sides, but for the long rails we use clear or fine quality 1x boards because they cut easier with fewer voids and in the case of the front rail can be shaved down well with a hand plane.

I've seen people only use glue on their joints but we glue and screw because you never know when your drummer is going to get a call on his cell phone while you're carrying your board up a flight of stairs. Drummers amiright!? Anyway, you'll need wood glue and screws #8 or #10 1 1/2 to 2 1/2 inches. And some wood filler for later.

And of course, don't forget the tolex and spray adhesive. Or shag carpeting, we're not here to judge.

Hardware

 Routed for the new butterfly latches. These don't need to be super precise so were done freehand - but be careful!

Routed for the new butterfly latches. These don't need to be super precise so were done freehand - but be careful!

As long as we're talking about materials, we may as well talk about hardware. I personally prefer to do away with the Fender stuff and install things that are really road worthy. If this board is not going to leave your house for the next decade and you want that original look - by all means go for it. Most importantly have an idea of what hardware system you want to use before you begin...or even better have your hardware in hand. Oh and don't forget corners and handles.

Step 3: The first cut is the deepest.

It's tool time. So you need

  • circular saw or jigsaw
  • table saw
  • clamps
  • router and round over bit (3/8" i think)
  • drill/driver
  • straight edge/level and square
  • countersink

That's not such a crazy list for a DIYer so hopefully most people don't need more than one or two of these smaller things. 

General rule of thumb- big cuts first so get the big top piece out of the way. I sometimes free cut it a little oversized so it's easier to guide through the final passes on the table saw. 

Plenty left over for the sides even if you mess one up. Draw everything out first. Essentially you're mirroring the dimensions of the base....so if it's 3" tall on the front board and 9" high on the back the front of your top will be 9" high and the back will be 3". You can extend these dimensions taller as long as you do it proportionately. Double check the clearance with the fiberglass cover in place over the tone bars.

Finally, once you have your sides complete, start running your long boards through your tablesaw at the proper angle cut. We usually do several passes starting on a very cautious oversized cut and slowly decreasing until we have a very close fit. Make sure you temporarily clamp the boards to accurately check the fit. OR wait to get the proper fit once the sides are installed.

NOTE: Some people prefer doing a lap joint, which Fender did for quite some time. Any jointing is possible and can make a for a wonderfully built enclosure. The limitations being your time, skill and equipment. 

Once everything is cut and you're happy with the dimension it's time to assemble.

Step 4: Assembly

We have the luxury of many good clamps and workspaces and I hope you do too because these boxes are pretty unwieldy. One way or another you need to set your pieces, preferably with glue, and then screw them in place. We highly recommend countersinking fairly deeply. The reason being that after your box is assembled if you want to round the edges you don't want to run into any screws! On that note, we usually start our countersinking slightly away from the edge and angle outward just a bit. Making sure to not miss the piece above but giving a little extra margin for the router coming after.

Start with the sides. Make sure they are square (perpendicular) to the big top piece. Sometimes we wait for the sides to be installed before we finish milling the long boards. Either way, same deal, install the long boards. We use a screw about every 6 inches or so. We drive the screws down pretty far so the heads are about 1/8-1/4 below the surface - again because the of the round over. If you used lap joints this is not recommended because you risk splitting your thinner overlap.

NOTE: We've ignored the hinged storage section for this DIY, but adding a storage section can be really useful and not very difficult.

Step 5: Finishing

The hard work is mostly done. Now it's time to sand, putty fill, sand again. During this stage we sometimes route for specialized hardware, but if your hardware mounts on the finished lid then it's time to wrap.

Wrapping your board should take some time because while it's simple it also easy to mess up. Start with the ends of the enclosure cutting 45 degree slits at the corners and then bending /wrapping the tolex around the outside corner about a 1/2 inch beyond the inside corner. This is by far the hardest part but once your corners are set the best thing to do is use a single piece cut exactly to length. Start at the inside  corner and work your way all the way around the lid. Use plenty of spray adhesive and keep a rag handy for any drips or spots.

I would normally finish with some cheery saying or motivational platitude but it's late and I'm sleepy so good luck out there. Comment or question and we'll try to get back to you.

The first things to wear out on a Fender Rhodes

Restoration, Action / RegulationMorgen SharpComment

There were roughly a quarter-million Rhodes produced during the CBS and Fender production years. We like to think that most of them are still around and it's safe to assume that most of them are under-serviced. So if you've just bought a Rhodes or are finally getting around restoring that dusty thing in the basement here are few places to start.

Grommets: These degrade regardless of use. The reason is that, unlike the hammer tips, they are a rubber product and not neoprene. Also they are under constant stress from both the weight of the tone bars and the pressure from the springs underneath. Many rhodes are also poorly serviced over the years, one of the most common examples being over-tightened tone bars. The bars should be spaced about 3/8" from the plywood. However because they're the easiest part to access and adjust many people use these to address other problems such as weakening bridle straps or poorly adjusted damper felts.

The original grommets were already prone to being squished out (which causes them to become dry and brittle even quicker) but over-tightening really destroys the grommets quickly. It rarely effects the strength/resiliency of the springs but this can also be something to look out for.

Worn grommets, particularly original grommets can also lead to a host of other minor problems beyond directly affecting the sound. Most importantly they can throw off the alignment of the tine in relation to the hammer tip, the felt and the magnet/pickup. For this reason and the tonal difference we illustrate in the following videos we recommend replacing the tone bar grommets before any other restoration is done.

Above are some old original grommets pulled off a 1978 Rhodes. Some of these actually crumbled when we removed them. You can see the "mushrooming" from the pressure of the springs and weight of the tone bars and also the uneven wear from side to side which will cause misalignment and make adjustment difficult. Our improved grommet is pictured also for comparison.

Below: as an experiment/demonstration we replaced every other tonebar with new grommets to show a side by side comparison of old versus new.

Next Up: Bridle Straps

Bridle straps are the key link between the hammer and the spring damper. They are simple cloth cords with reinforced tips. Used normally in the upright piano action they are put in a different situation in the fender rhodes. Most importantly they are under a constant and variable amount of stress whereas in upright pianos the bridle strap is normally slack except when involved in the key/hammer return. Because of this we recommend a "heavy duty" bridle strap with a very strong reinforced tip. But no matter what, the bridle strap is under an unusual amount of stress in the Rhodes design.

*Quick note: replacing bridle straps is not hard....but it is tedious. We usually use a new clean razor blade to first work the glue away then slowly work the braid out of the hammer slot. The most important thing is that you take your time to avoid breaking any of the clips. The blunt edge of the utility knife blade can be used to gently push/wiggle the new strap into the hammer clip.

So back to this unusual stress. The damper spring is constantly pulling on the bridle strap so even in barely used instruments the bridle straps are often degraded. This can be something subtle like a a slight stretching or tearing around the hole all the way to being full ripped which totally disables the release of the felt damper as the hammer comes up. We often tell people that replacing the bridle straps is by far the best "bang for the buck" as they're a pretty inexpensive part and the feel of the action is hugely dependent on them. Properly tensioned and intact bridle straps enable proper damper let-off and they also assist gravity with key return - making the keys feel "faster".

*Another installation note: stretch your bridle straps! Simply hold the tip and squeeze the cord while you pull away. Doing this will help give you a more consistent tension during installation and avoid any straps becoming slack as time passes.

 

Number Three: the Damper Felts

Some people think hammer tips should be on this list - but really they only degrade with wear. Felt dampers on the other hand (and in some cases foam dampers) do succumb to the ravages of time. And sometimes bugs. For that matter any of the felt on your Rhodes - like the key rail punchings or the name rail felt can become downright useless with little more than aging. (Moisture and temperature also play a big role.) But damper felts are often the first felt product to need swapping out.

 Yikes. Here are some really poor quality notched felts. The tine has even carved a hole in one.

Yikes. Here are some really poor quality notched felts. The tine has even carved a hole in one.

 

The Rhodes has had a considerable amount of variation concerning felt dampers over the years. For the most part Fender used a square or rectangular felt damper of varying size but as I mentioned earlier they also experimented with notched foam, notched felt and angled pieces of dampening felt in order to affect the damper travel and maximize the release. The most substantial change coming with the Mark V where the hammer rail was rearranged and the placement of the damper springs changed.

 Another alternating example. The original felts on this board aren't too bad but there is a lot of variation in how they have worn. You can see how the notched felts are taller overall but the dampening point is still about the same height.

Another alternating example. The original felts on this board aren't too bad but there is a lot of variation in how they have worn. You can see how the notched felts are taller overall but the dampening point is still about the same height.

Whichever style of felt they used in the factory most replacement damper felts will fit and function normally. There are some advantages to both the square and notched replacements. The square ones ensure a clean let-off and require less adjustment or fine tuning of the action. While notched felts dampen better, keep the tine centered and minimize vibration from other sources (playing other keys, sitting next to a drummer etc..)

Final Note: For a lot of people dead keys or sour notes are addressed one by one as they arise. But ultimately while some parts of the Rhodes should last a lifetime - others were never meant to last longer than a decade or two at most. If and when you're ready to start refurbishing your Rhodes look at these parts first to make the restoration go easier. Focusing on these parts first will make adjusting and doing further restoration go much more smoothly and help in identifying issues in other areas.