Author Topic: Homemade electric piano  (Read 622 times)

Offline gotkovsky

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Homemade electric piano
« on: December 22, 2020, 05:46:33 AM »
Hello everyone,

I’m a new member on this forum and this is my first post. I’m french, so please excuse any english mistakes, I’ll try my best.

I’m a musician with a fine-arts sculpture/design background, and I’ve been working for about a month now on a homemade reed electric piano, mostly based on the Wurli 200A, as one can find quite a lot of informations online on this great instrument. Electric pianos are quite rare and pricey in France (a Wurly in good condition costs about 2500€), but this is not really what motivated the project. I just like going back and forth between music making and woodworking and thought it would be nice to build an instrument for my own use as a musician. I’ve got plenty of time, don't really feel like making music these days as I just released an album, so, why not?

I’m lucky enough to have a workshop with the essential machines and tools to work accurately with hard wood. I also have a fair stock of exotic wood (not sure what it is, probably padok) at my disposal, which could fit the task as it is very straight grain, almost doesn’t warp with humidity changes, and is quite tough. A good friend also lend me a 3D printer which is gonna be helpful for making very small parts.

I’m creating this thread for two purposes. The first one is documenting the process for me and others to see, second is being able to ask very specific questions on parts, materials, etc., as this forum seems to be full of great people with lots of experience.

My idea is to make a sort of Wurly/Rhodes hybrid, basically a passive Wurly with electromagnetic pick-ups. I’m currently making a first prototype of a one-octave piano, from C3 to B3, and if it is interesting enough I’ll be making a 64 notes version. I spent a good two weeks of reading every article I could find on the subject, and later came-up with a first 3D model.



The action is a copy of the 200A, based on the handmade drawings of the service manual, which might sound crazy but these drawings seems to actually have the right proportions, as I already built one action and it seems to work fairly well.



My plan is to start by building one complete action and fine-tune it until it feels perfect, and then hopefully build the rest. For now I made a first action, which is of course far from perfect. The jack spring (which makes the fly return to its home position) and the damper spring (which makes the dampers return and press on the reeds) are still missing, as I still have to try out different wire sizes/lengths/numbers of loops/shapes, and also ways of fixing them to the action parts.





In order to post stuff regularly and to do things step by step, for now my focus is gonna be on the action parts, so I won't talk as much in this first post about reeds, keyboard, pick-ups, sustain pedal, etc., but I'll obviously came to these later as I work on it more specifically. That said, I already prototyped a working electromagnetic pick-up with 3D printed plastic sleeves or holders, 3D-modeled the keyboard and the enclosure system, and also tried different reed shapes and materials (I might do different than Wurlitzer reeds, as their stamped shape is near to impossible to reproduce with common tools, at least without spending one year filing hardened spring steel).

So I hope this project might interest people here, and that some of you will be able to help answering very specific questions, as many will come! I also wanted to thank everyone on the forum who came with infos, as it's been a great place for me to understand all the parts functions of electric pianos.

Offline bourniplus

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Re: Homemade electric piano
« Reply #1 on: December 22, 2020, 08:50:15 AM »
Super! Je vais suivre avec intérêt!

Offline gotkovsky

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Re: Homemade electric piano
« Reply #2 on: December 30, 2020, 02:01:59 PM »
So a first update on the project!

I spent two days trying to build a kind of asymetric tuning fork like the Fender Rhodes, basically reeds attached to a tone bar with the same pitch, to see if it could improve the sustain of the reeds, but I had very little success. So I decided to make a first pick-up (actually not exactly the first one if I count a few early tests), and see how the sustain was with the few reeds that I've made so far, without any tone bar.

The reed that we hear in this video is I think D2, going through a Roland JC-40 amp:

https://www.youtube.com/watch?v=G4XuNBs74OU

I'm actually fairly happy with the result, the sustain is quite good and the tone is nice. My phone's mic obviously doesn't really do it justice, and I should definitely try several ways of recording the output (DI and miked-up amp), but I'll do that when I'll have a full octave ready.

This working pick-up and reed combination, plus the sort-of functioning action gave me enough confidence to start building the first prototype of this piano, which is gonna be a single-octave keyboard from C2 to B2. So I built lots of small jigs to be able to cut the action pieces and drill holes into them accurately (and most importantly consistently). I printed templates of the actions pieces and a special table-saw sled with a series of stop-blocks to help cutting the right widths:




Here are the drill guides:



And the 12 actions parts roughly cut, they still have to be drilled and their intricate shapes cut with the bandsaw, which I'll do tomorrow.









« Last Edit: December 30, 2020, 02:04:07 PM by gotkovsky »

Offline epluznante

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Re: Homemade electric piano
« Reply #3 on: January 24, 2021, 09:19:27 PM »
Wow! incredible this thing sounds amazing!
Also: I love you
I was hoping to see something like this. your example gives me hope :)     ---I always dreamed of being able to do a similar project. Where I live it is practically impossible to get an electric piano. There is no offer and to buy internationally paying the shipping costs is IMPOSSIBLE.
I have studied the plans of rhodes, wurlitzer and hohner thinking of different combinations of action + pickups + reeds. I tried building a wooden action with a poor version of pickups (and even a guitar pu) and I tried different materials for the resonant parts but didn't like the result and was losing hope at this point

because I have not found examples on the internet of a good sounding diy EP... so ... finding your project really gave me hope!

Offline gotkovsky

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Re: Homemade electric piano
« Reply #4 on: January 25, 2021, 04:27:16 AM »
Thanks epluznante for the kind words, it's nice to see that someone else is trying to build an homemade ep too! What is the material that you used for your reeds? And could you post photos of the actions that you put together? Is it a reproduction of the Wurly action or did you came-up with something new? Making action parts is probably the most challenging part of the project, as it's really small and needs to be precisely made. I found that cutting the recesses accurately (in the whippen assembly for example) in which the flanges will fit is the most difficult task, as it was probably made with custom machinery by action parts manufacturer. For now I'm cutting those recesses with the table saw and clean them with chisels and files, but I'm not 100% satisfied with the results as some parts have too much side-to-side play when assembled with the flanges. I still need to try to cut these with a router and a custom jig made for this very purpose.

Ideally these recesses should look like this (I took this image from someone of this forum who 3D-modeled an entire Wurly, hope it's ok):



That could be done with a router and a special plunge bit, but I couldn't find anything like this anywhere, so personnally I'm just cutting them flat and it works ok.

For reeds I had the best results with XC100 spring steel which I bought in 5m roll, it's basically feeler gauge material, and it sounds good even if it's cut quite roughly. Don't hesitate to ask for anything if you need to, I'll be happy to help!

So back to the project, right now I've prepared 12 actions:


I'm actually not sure to use these as I'm not completely happy about how they turned out, I'm might redo some parts again with another method involving a router to cut the whip assembly recesses.

Then I worked on the balance and front rails:


The front rail is quite easy to make, the balance rail is more difficult as there's 3 bevel cuts in the same piece. But it's doable with a table saw, a featherboard and patience.

Then cutting 12 keys:


I'm also not quite sure about my method for making the keyboard, as it turned out to be not perfect at the end, but I'm pretty close. The traditional way of making a keyboard is to glue several boards with the grain running in the width, draw the layout of the keys and mortises on this glue-up, then clamping or nailing the whole keyboard to the keybed with the front and balance rails also attached to the keybed, drill all the holes in the keys and the rails at the same time, and then cutting all keys separately. This way the locations of the pivot pins in the rails are pretty much perfect. I chose to do it differently as I don't have a good way to cut the keys accurately from such a big piece. So I chose to cut each key one by one, and then glue them together (using non-permanent glue) with 1 mm shims between them (and 2 mm between the end of the sharps where they meet the naturals):



Then I positioned the assembled keys in the keybed on top of the rails, and I punched the holes positions into the rails using a 4 mm nail, which is what i'm using as the pins by the way.

Next I removed the keyboard and the rails from the keybed and drilled 3,5 mm holes in the rails, using the divets left in the rails by the previous operation:



And finally placed the keys on the rails, and added keytops to each one of them to lock them in their best positions:



I'm of course simplifying here, I'm not talking about how to cut mortises and gluing felt in the mortises, so if anyone needs informations on that, once again, don't hesitate.

So this method for making the keyboard turned out to be pretty ok but definitely not perfect. A few keys on the right part of the keyboard don't sit completely straight (there's a 1 to 2 mm difference in parallelism from the front rail to the end of the keys for the last 4 keys). But I think I know why: when positioning the assembled keys with shims on top of the rails, I also positioned two scrap pieces as spacers on both sides of the keybed, which also acted as wedges to lock the keyboard in place. These two spacers' width where cut according to my 3d plans at 23 mm, but in reality they didn't fit perfectly on the sides and I had to force them too hard to do so, which had the effect of compressing the keys between them, as wood (and paper shims) have a bit of elasticity in this grain direction. And that probably misplaced a few of the pins locations. I also have to be more careful when punching the pins holes in the rails through the keys, using a self-centering punch tool would be also better than a nail.

Offline epluznante

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Re: Homemade electric piano
« Reply #5 on: January 25, 2021, 08:52:56 PM »
Hey great update your system looks great!

And-- as for my attempts: I tried the action of the wurli which I copied from the service manual cutting it directly on mdf. The system was not perfect and the movement wasn't smooth but I prioritized the study of the sound generation...in which I did not find a satisfactory result. I also tried the action of the hohner pianet (with the sticky pads) as it is a lot simpler than the wurli's.
As for the sound I previously made my own guitar pickups with different variations (((currently I'm working on a handmade guitar))) so I tried to make a pickup aiming for 175- 190 ohms as recommended in a video from vintage vibe. And apart from that I also tried with a pickup with an impedance closer to that of a guitar. And for the reeds I tried different pieces of metal that I had around at that moment because I couldn't find any precise info on that. I even used a piece of plastic with a metal part on one end this was used on the hohner type of action bc it was easier to move with the sticky thing. THe metal parts that I used sounded good acoustically and was kinda easy to get in tune but the sound through the pickup was very weak and not very close to what one could expect. And the plastic version surprisingly produced a more clear sound but the dynamics were totally out of control and the sound neither was EP-like.

in short I never found a working combination of reeds + pickup + preamp.

And currently your post is making me interested again and giving me ideas to try and your info on your reeds is super useful thanks again!

Offline gotkovsky

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Re: Homemade electric piano
« Reply #6 on: February 14, 2021, 12:45:27 PM »
Hello!

Today is a lazy sunday for me so it's perfect to write a little update on the project. I've kept working on the prototype, got six actions and reeds working nicely, but as it's so much work to fit every action, I thought I'd stop there on the prototype and start to work on the real thing. And oviously keep the prototype close if I need to test anything.

I modified a bit the design of the casing and gave it a bit of a Wurlitzer 110 look. I'll be using some kind of wooden profiled rails to hold some sheet metal, which will be painted with automotive paint and clear coat, as I have some experience with that. I also designed the sustain mechanism which is a little different than the 200, not sure if it will work properly but I'll see as I go!




I started by working on the keyboard, which is almost done as I'm writing. I used a method that is a bit unconventional and might seem overly complicated, but that fits the tools and skills that I have (or don't have). The traditional method for making a keyboard is to draw the layout of the entire keyboard on a single glued-up plank, and then cut all the keys free with a bowsaw/bandsaw and chiseling or scrollsawing where the front of the accidentals meet the naturals. As I wrote previously, I don't have the skills to cut so many straight lines by hand accurately, and I don't have enough rooms on my bandsaw to cut in the middle of the keyboard. But I have a good table saw and sharp chisels, so I decided to cut each key one by one on it and then fine-tune them by hand. The keyboard rails are also done with the table saw, jointed with open tenons for the right and left crosspieces, and a wide dado for the middle one.



Then I printed a 1:1 plan of the whole keyboard.



And glued (with non-permanent glue) the back of each key on it, using paper 1mm shims between the few keys that were not sitting perfectly flat, probably because these warped a bit after they've been cut, as it's winter.



Then I nailed two rails to each key to keep them in position.



The balance mortises were already cut on each key. I then positioned the keyboard assembly on the rails, clamped them together, and transfered the balancing pins holes location by drilling about 2 mm from above the key with a handheld drill. Then I removed the clamps, put shims under the balance rail to level its bevel flat with the drill press table and drilled all the balance holes.





After that was made I cut 64 pins out of 4 mm coated nails, and chamfered both their ends by putting them in the drill press and using first a coarse file and then a finer one. These nails are pretty smooth to begin with, but definetely not as much as real chrome plated piano pins, so I'll hope it'll do the job. I can always polish them later if that's an issue.



Then nailing the 64 pins in the balance rail. I hammered about 10 pins by hand, checking with a square that they were straight according to the balance rail bevel, but that took forever, so I made a simple jig to help me guide the pins.



The pins were a bit too tight on the key balance holes, so I reamed and burnished every hole by putting a spare pin in a drill and wiggling it a little in the holes as it was turning. Then I flipped the keyboard and inserted the balance rail in it. Yes lining up 64 holes at once is a true woodworker's delight.



It took quite a lot of banging with a big mallet, but I managed to do it. I was afraid I might elongate the balance holes in the keys by hammering them so hard in the pins but that actually didn't happen. So far so good.



Then I pivoted the whole keyboard on its pressed position on the rails, add shims under the front of the keys to avoid chip-out and level the keyboard, drilled through each key at the center of their mortises (which are not cut yet) and also through 2 or 3 mm of the front rails. Have a look at my very sophisticated drill press table.



Then I removed the keyboard from the rails, removed the rails holding the keys together, and finally finished drilling all the front rails holes. So that's where I'm at right now.

If you read this and consider building a keyboard, I'd strongly suggest not to use this method and instead use the traditional one, as it's way simpler than mine and surely more accurate. If I had a bandsaw with more than 40 cm of elbow room, that would not have a been a question for me, but once again I'm limited by the tools and skills that I have, and my method also works, it's just more complicated and requires more fitting once the rails holes are drilled.
« Last Edit: February 14, 2021, 12:47:36 PM by gotkovsky »

Offline sean

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Re: Homemade electric piano
« Reply #7 on: February 15, 2021, 10:00:41 PM »


Fantastique!
Merveilleux!
Putain de cool!



I like it.

Sean

Offline drpepper

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Re: Homemade electric piano
« Reply #8 on: February 16, 2021, 05:10:13 PM »
I am looking forward to see how this works out. So far it looks amazing.
I have been working on my own rhodes/wurli inspired DIY piano design but it needs some work.
Rhodes Suitcase 75
Wurlitzer 200a
Gibson es 335

Offline gotkovsky

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Re: Homemade electric piano
« Reply #9 on: February 21, 2021, 08:33:23 AM »
Thanks Sean and drpepper for the kind words! Drpepper, could you share a bit of your design? I'm curious!

So I'm still working on the keyboard, and I started with the naturals.

I bushed all the fronts with 1mm strips of actual bushing felt, using small amounts of regular wood glue and homemade wooden cauls to clamp the bushings. The narrow parts of the cauls are actually 4,1 mm, so that should leave a very small amount of play with the front rails pins which are 4 mm. I had to fine-tune all the front key mortises with a mortising chisel and files, so that the cauls would fit perfectly (snuggly but not too tight). I also have different bushing felts rolls in increments of 0,1 mm in case I file a little too much and there's too much play.





Then I worked on the key buttons. The Wurly 200 doesn't have key buttons, but I decided to use these as it makes things easier. I first routed 1mm grooves on both sides of several cross-grain rails. These grooves are cut so that the felt sits flush with the top and bottom surfaces of the buttons.



Rounding-off the fronts and backs of the button rails, using the belt sander.



Marking-up the positions of three 5,5mm holes for drilling the mortises on the drill press.



Drilling the mortise. Using a drill to cut the mortises is not the best, I thought about making a homemade tool for this, consisting of two chisels glued back to back to ensure the parallelism of the mortise, but ended up continuing with the drill press as I got quite good at it. Drilling the mortises instead of cutting them leads to more fitting afterwards, but I'm fine with that.



And then cutting the key button on the table saw using a crosscut sled and a stop-block.



Then I bushed all the key buttons, using the same procedure that I used for bushing the key front mortises.



I was a little nervous about gluing the key buttons without knowing if the naturals where running perfectly perpendicular to the front/balance rails and level with the keybed, so I made two reference rails with pencil marks on both the front and back of the keys.

 

These rails are nailed directly into the keybed.





Gluing the key buttons. I used wood glue and a few drops of CA glue to hold the buttons in place while the wood glue dries. I had to press on the buttons with my fingers for about 5 seconds, which is enough for the CA glue to bond, then remove the key from the rails and clamp the key button to the key with a spring clamp.



Then trimming-off the key buttons flush with the keys using a hand-plane.





So I almost finished to glue all the key buttons to the naturals, and reamed a little bit of the keys balance holes to limit friction. I'm a bit worried because this morning I noticed that I had quite some play in the keys in their up-position (not pressed), and I can't find info about what is an acceptable amount of play in the key bushings and key buttons. I guess as long as the key are not rubbing against others, it's sort of ok, but it'd be best to know what is the standard amount of acceptable play, so if anybody can shime in that would be great!

Right now I have between 0,6 and 0,7 mm of play in the naturals (which is a tiny less than 1/32 inch for american friends), measured at the back and front of the keys, in their not-pressed position. Does that seems too much? I have to say that I still didn't polished the pins, which I should have done before bushing everything, damn me%u2026 and I also don't have an acoustic piano around to compare.

So, should I rebush the keys front mortises and key buttons using 1,1 or 1,2 mm felt instead of the 1 mm I used, or is 0,7 mm of side-to-side play in the keys acceptable? Theoretically 0,7mm is too much, as I only have 1mm of clearance between each key. Here's a link to a video showing that: https://youtu.be/mEnoQPDt0o0

I also have to mention that it's winter, so the wood of the keys might shrink a bit when summer will come, and therefore tighten the mortises a bit. Should I take that into consideration? I also guess there's a bit more friction in a brand new keyboard than one that has been played for years. I'm pretty ignorant on this subject, so if any of you experienced piano tuners could enlighten me, I'd be very grateful!

Wish you all a great sunday!

Offline Cookymonster

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Re: Homemade electric piano
« Reply #10 on: March 11, 2021, 06:51:22 AM »
Eager to see your progression...Respect....
I will turn all my mountains into rhodes.