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This is my first version of a usable twistable shaft for vibraphone fans. The concept enables the use on most vibraphones (e.g. Musser M55) for a more or less DIY-self-adaptation as a retrofit kit while continuing to use the existing drive unit.
But it took a rainy November weekend to fit the fans and coupling elements together.

That's what I've been looking for for years.


BarryK Fri, 12/11/2020 - 09:21

To have the option of having them twisted or not, depending on the rotation direction is brilliant!

And the motor is cordless!? How long does the powerbank last?


wyndorps Fri, 12/11/2020 - 09:28

In reply to by BarryK

Thank you.
I don't know how long the powerbank last. It's still running since several hours!
But I am not yet lucky with the motor. I want it to become more quite.
This was a strong NEMA 17. As there was much more torque than necessary I will next try a small NEMA 14 stepper motor.

wyndorps Fri, 12/11/2020 - 11:23

In reply to by IndianaGlen

In my frame concept I use two motors, one for each row of resonator tubes. That's why I had an electronics student develop my own controller. It uses two pieces of A4988 drivers on a common board.
HTH Paul

BarryK Fri, 12/11/2020 - 11:03

In reply to by wyndorps

How do you determine the size motor needed? Trial and error, or can you measure the torque?


wyndorps Fri, 12/11/2020 - 11:35

In reply to by BarryK

Both shafts are mounted in roller bearings. These have only very low friction losses. Acceleration is also not a problem as the masses are small. So you hardly need a moment. In the first version presented, I used a NEMA 17 motor with a Max Holding torque of 340 mNm because it costs almost nothing (<3 €). The torque is so strong that I can't completely brake the shaft with two fingers.
In order to reduce the hum from the step control, I have already made an experiment with a NEMA 14 with 100 mNm. That worked without any problems, but I still have to adjust the motor mount for the attachment.

robwaring Sat, 12/12/2020 - 07:15

Congratulations! What a fabulous idea. A true innovation. I hope you will post a recording soon of the vibrato effect with twisted fans. Can't wait to hear this!

Randy_Sutin Sat, 12/12/2020 - 09:36

I have a favorite old M55 with several broken fan blades that I keep duct taping and glueing back in... This would be an awesome repair with added functionality.

I love the concept. Please keep us in the loop when a retrofit kit is available.

I am in awe of the idea!

wyndorps Sat, 12/12/2020 - 12:29

In reply to by Randy_Sutin

The next step is to make the shafts foldable despite the possibility of twisting, because my resonance tube holders are also foldable. It's pretty tricky.

My approach for a retrofit kit is to manufacture and ship the difficult angle coupling elements (which are very small, but unfortunately not cheap), together with a set of sheet metal fan halves and the drive wheels.
The sheet metal fan halves can then be adjusted a little with tin snips if necessary. After that, they just have to be glued. None of this is complicated and a good job for a rainy weekend :).

Since I don't have an original Musser myself (only Musser bars), I need someone who can take a few exact measurements to define a suitable retrofit kit. In particular, the mount for the rolling bearings must be designed to match the resonant tube brackets.

IndianaGlen Sat, 12/12/2020 - 13:27

In reply to by wyndorps

I certainly can measure my M55 fans/resonators. My suggestions would be to get more than one set of measurements. I assume due to Musser's manufacturing processes measurements tend vary from year to year (and even from vibe to vibe).

let me know how I can help.

Randy_Sutin Sun, 12/13/2020 - 19:18

In reply to by wyndorps

I will also measure my M55 later this week for you so you will have one more set of measurements.

Wow. This is exciting. Ever since I saw the old Deagan with those offset fans, I've wanted that sound... especially in conjunction with a variable speed motor, which the old Deagan did NOT have.

IndianaGlen Mon, 01/04/2021 - 14:43

In reply to by wyndorps

Attached are a table of measurements and some photos of my M55 Resonators. Since my resonators are different than your PDF drawing, I thought the photos may help for reference, and I certainly can double check or take additional measurements.

I included nominal/assumed measurements in inches and I also used cm since the resonators were made in the USA and likely were made from USA materials.

Again, I'll be happy to double check or include additional measurements. Don't build anything for an M55 based on this first cut draft.

Babu Sat, 12/12/2020 - 15:54

Me too, i can measure what is needed to be mesured on my M55. Just tell exactly what you want .
Brilliant ideas all along the process ! You make us dream of "the perfect vibes" :o))

wyndorps Sun, 12/13/2020 - 11:51

In reply to by Babu

Of course, I can't do anything at the moment anyway, as we're in corona lockdown. I can't even get my current frame parts to anodize. So it will be a natural aluminum frame.

Babu Mon, 12/14/2020 - 05:05

In reply to by wyndorps

OK, that's fine.
I saw the news yesterday about german lockdown. Good luck ! We in France are partly out starting tomorrow. We'll see what happens with all that...
Take care
Best - Babu

wyndorps Sun, 01/10/2021 - 12:15

First M55-Design of Twistable Fans

Hello everybody, thank you for your measurements.

My impression is that the resonance tubes of the M55 can be quite different. I do not understand what Musser have a special formed fan in the middel or not. It seems as if not all Musser have bearing blocks in the middel position, ...
So it is diffcult for me to create a common design.

I have tried to construct a solution that is as uniform as possible, but I am not entirely sure about the dimensions of the pipe positions relative to one another and about the location of the bearings, as there were different details here. I made my construction accessible as a 3D PDF (attached file: Resrohr_0000127234.pdf).
To use this supporting file download it using the right muse button and choose "Save link as ...".

It would be good if as many M55 owners as possible will take the opportunity to verify the data from this file.
I don't have access to an M55 (not least because of corona lockdown).

I have also attached a link to a video on how to use the 3D PDF.
The necessary parts can be made from plastic as a high quality 3D print. Corresponding providers are now very widespread on the www - unfortunately more expensive than I had thought.

I have prepared a second alternative design in which only the coupling pieces are 3D printed. The actual flaps can then be cut to size from ABS with scissors and glued in place. Surprisingly, when I asked for it, the coupling pieces were hardly cheaper in total than the entire 3D print valve. However, you have more options to adjust the size of the key to your personal sound expectations, but glueing is a bit tricky.

I had carried out such a solution as a test with metal flaps in coupling pieces, but 2mm thick ABS should be sufficient.

A third, very simple solution is to use 3-D printed flaps that clip onto a shaft. This is ideal for testing whether you even like the twist. This is rather unsuitable as a permanent solution, as it is too easy to lose the flaps.

Stay healthy and have a happy new year

Supporting Files

wyndorps Sun, 01/17/2021 - 08:01

In the meantime I have finished and tested the first flap unit completely 3D printed except for the shaft. A few optimizations and adjustments resulted from the test. So now I have a final construction fitting to my resonance tubes.

I also have all the data already incorporated into a design for Musser M55, as far as I have concrete measurements. Unfortunately, either the measuring equipment and measuring possibilities are very different, or the Musser resonance tube units are somewhat variable. Therefore, based on the data I have received, I cannot reliably release a design that fits all M55s at this time.

The restrictions because of Covid 19 make it impossible at the moment to go to an owner of an M55 and make own measurements.

As a next step I will try to make my flap shaft including the twisting unit divisible so that it can be folded with my tube holders.

Supporting Files


What instruments does this pertain to?

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