Author Topic: DIY £20 Wurlitzer Pedal  (Read 310 times)

Offline drpepper

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DIY £20 Wurlitzer Pedal
« on: February 13, 2021, 06:30:02 PM »
My Goal was to create a 3D printed Wurlitzer sustain pedal that would be affordable. The original design is reasonably basic, a wooden box with some cast fittings and what I guess is a motorbike clutch cable. When the pedal is pressed it pulls the cable that then pulls the exposed threaded rod on the bottom of the Wurlitzer piano and disengages the dampers.
With the prices of electric pianos sky rocketing, so have some of the accessories, there are original Wurlitzer sustain pedals for sale now with a buy it now that’s higher than I have paid for complete pianos.

 
Pedal Design

 
End Fitting Design

Parts List and Costs
•   PLA 1.75mm Filament £15/kg Total £4.52
o   Pedal – 56g - £0.84
o   Enclosure – 200g - £3.00
o   Access Door – 12g - £0.18
o   Cable Clamp – 1g - £0.02
o   Hose Clamp – 5g – £0.08
o   End Fitting – 17g - £0.26
o   Ferrule – 9g – £0.14
•   1x Spring
•   1x Bicycle Brake Cable – £3.99
•   1x 2mm Aluminium Sheet - £6
•   1x Self Adhesive Velcro Hooks
•   4x M3 x 20mm Socket Head Cap
•   2x M3 Nuts
•   2x M5 15mm Hex Head
•   2x M5 Nuts
•   1x ¼” UNC Nut *
•   1x M6 x 35mm Hex Head bolt
•   2x 3mm x 15mm Wood Screws
•   2x 3mm x 30mm Wood Screws

Note* - This nut is the most important item to get correct. Using the wrong size will damage the piano as it will damage the threads on the piano. A M6 nut will feel like it fits for a turn or two then it starts to damage the piano.
The parts I haven’t put a price on are stuff I have laying around. Though I don’t think these would add to much so I have assumed £5 for these are any good fastener specialist could gather up for you.
 

Pedal – Part Design
 

Pedal – Cable Clamp
Two M3 20mm bolts clamp the brake cable to the clamp. These do not require nuts as the tolerance is tight allowing the bolts to thread into the pedal.

 
Pedal Hinge
M6 35mm Bolt provides a pivot for pedal.

 
The clamp plate above the pedal features a bracket to allow the spring to connect the pedal and the enclosure.
 

Spring Connection on Pedal


Enclosure – Cable Outer Clamp
The enclosure has a removable side panel, that allows all the clamps and bolts to be inserted and adjusted.
 

Side Access Panel


End Fitting - Assembly

The brake cable needs to be threaded though the ferrule and then the ¼” UNC nut can slot into the end. The end fitting has a clamp to hold the brake cable outer. 2 x M3  20mm bolts are used in the clamp. The end fitting a little longer and wider than the original as this now made of plastic, the extra size makes up for the loss in material strength.


3d Printed End Fitting
 

Finished 3D Printed Pedal

 
Finished Pedal next to original Pedal
The 3D printed part is created in layers, these show up in the photos and can be felt with a finger, but during use this only adds grip.
 

Comparison with Original

Weight
Overall the weight of the peal has dropped significantly.
Changes:
•   Steel replaced with aluminium for base plate
•   Rubber replaced with Velcro for grip surface
•   Metal replaced with plastic for pedal
•   Metal replaced with plastic for end fitting
•   Small diameter cable and housing

Print Time
•   22 hours.
o   Pedal – 3 hours
o   Enclosure – 13 hours (Compromises in print settings were made to reduce this)
o   Access Door – 1 hour
o   Cable Clamp –  1hour
o   Hose Clamp – 1 hour
o   End Fitting – 2 hours
o   Ferrule – 1 hour
 

The Enclosure Mid Print

Function
As the pedal geometry is based on the original the pedal feels the same as the original. After a couple of hours playing, I saw no issues. 

Summary
The pedal performs just like the original for a fraction of the prices of a replacement. Will it last another 50years – I doubt it. Can it take the same load as the original – I also doubt it.
Does it cost a fraction of price and do the job it needs to – yes.

Rhodes Suitcase 75
Wurlitzer 200a
Gibson es 335

Offline sean

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Re: DIY £20 Wurlitzer Pedal
« Reply #1 on: February 13, 2021, 09:06:26 PM »

This is fabulous!  ...and abnormally cool.

Is the PLA pedal lever really stiff enough?  Wow.

Excellent idea.  Excellently executed.


I have always thought that the Wurly pedal sits up too high.  Could you re-do the drawings to get the lever an inch lower?  I mean just delete the bottom inch of the green housing.  Green?  Why Green?

Awesome.

Sean

Offline drpepper

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Re: DIY £20 Wurlitzer Pedal
« Reply #2 on: February 14, 2021, 10:32:46 AM »
The lever is stiff enough you cant feel a difference, I think if you put all your weight on it there might be issues, but  the same could be said for the original pedal.
Yes it would be easy to make changes to lower the pedal or change the shape - there is no reason its this high that I can tell.

Green was just PLA I had at hand that wouldn't look too out of place. 
Rhodes Suitcase 75
Wurlitzer 200a
Gibson es 335