Tines steel type

[wildebram]

Hello everyone,

Me and a friend of mine started a little project on the rhodes piano a few days ago. We have the wild idea to eventually build something ourselves that comes close to it..
But we decided to start out with making a pickup and buying some steel rods to test whether we could get decent sound. (before building a piano mechanism).
After some hours of troubleshooting the pickup finally worked, but the steel rods we ordered did not give any sound. We tried it with a knife of stainless steel and that actually worked.
The rods we ordered are supposed to be stainless steel (diameter: 2mm, length:200mm), but we are not sure if they are. I tried to find what kind of steel the original fender tines are made of and found this post, which says they are 904 steel: https://www.gearslutz.com/board/so-much-gear-so-little-time/177125-fender-rhodes-piano-2.html
The most common type of steel is 304, so my question is: do you guys think this should work with a thin rod of 304 steel as well? (I'd rather not order useless stuff again  )

Thanks for reading,
Bram

[OZDOC]

A couple of thoughts:
The tines in a Rhodes are coupled with a tone bar - so they're effectively one arm of a tuning fork. The tone bar allows the tine to oscillate for longer. So your rods may not have oscillated for long enough for you to hear anything.

Rhodes tines are drawn (stretched) to align their molecular structure and work harden the material so it rings better.

The purpose of the 904 steel is probably to find a specification that is less susceptible to stress fracturing from tiny imperfections on the rod surface so the tine lasts longer under repeated impact.

It took Rhodes many years to work through these issues.
Look forward to hearing your progress in 2020:-)

[sean]

Having the tuning spring on the end of the tine makes a huge difference too.  That lump of mass at the end of the rod is really important if you want the lowest wavelength to dominate the sound.

Try pulling the tuning springs off a few tines in a Rhodes.  The result is not beautiful.
The difference is more pronounced on the shorter tines.

The tines in the Rhodes are not as thick as 2mm... try 1.5mm.


I can't imagine your motivation to try this....
Is this part of some Mechanical Engineering homework project?
(I am less upset about this if I imagine that this is the case.)

I think there are a lot of issues that need to be resolved before you decide that your plans have failed due to the wrong steel alloy (tine mounting, sustainer/resonator/tonebar, ideal strike point for each length of tine, etc.).

The fact that a butter knife in a diner can resonate beautifully is proof enough that the alloy may not be the dominating sonic factor.  Also, circular saw blades resonate beautifully, and so do garden shovel blades.  Hmmm....

While you are at it, you should test brass and bronze tines too - you would have to fit them with a steel or iron tip to work with the passive magnetic pickup, but it would be interesting.

If you are set on the larger diameter (2mm) tines, maybe you could thread the ends, and the tuning device on the tip of the tine could be screwed into position.

If you like the resonance of bronze, you could go with an optical sensor... oh, but this would probably require cooperation with the Electrical Engineering Department....  But that should be easier than the hassles you will have with Californian patent lawyers. 

Good luck with this, I hope it turns out to be fun, and eventually, musical.

Sean

[wildebram]

Thanks for your reactions 

About the resonance: we were aware that the steel rod does not nearly have the resonating properties is has when coupled with the tonebar in a Rhodes fashion. However, when we pinched the rod between our finger and the edge of a table (halfway the rod), we could actually get the whole table resonating. And still the pickup gave literally nothing. Also when we tapped the pickup with the knife we heard a bit of a pang, but with the rod again nothing.

So reading your comments I am more and more tempted to think that our steel rods are simply not made of steel (they were ordered from ebay somewhere, not entirely trustworthy).
I guess I will try to find other tines that maybe are thinner and definitely steel and start proper experimenting on the resonance and sustain etc. Your ideas certainly made things more clear

As for the motivation: we are doing this entirely for our own fun (I am a physics student though

[David Aubke]

Forum member Kapucha007 has been working on a homemade Rhodes for a while.
http://ep-forum.com/smf/index.php?topic=7311.0

[sean]

Hold on a second.  I think I am wrong.  I guess the choice of metal alloy is more important than I thought.  I never considered that some metals might not work well with the passive magnetic pickup.  (I was just thinking about the vibrational resonance tone-generating properties.)



I now realize that you would have to use an iron or steel tip.  You need a lump of moving metal that has magnetic permeability that is significantly different from air.  Okay, if you do want a high permeability tip, then Iron is way better than stainless steel, and way better than copper (and so probably better than bronze and brass).

See  https://en.wikipedia.org/wiki/Permeability_(electromagnetism)#Values_for_some_common_materials

Hmmm...  the permeability of stainless steel is very close to the permeability of air.  The permeability of iron is very very different from the permeability of air.   Looks to me like iron will be a hundred or a thousand times louder than stainless steel.  Wow.  Well, convert that idea to decibels, and well, iron is louder.  Well, that can't be the right way to calculate the difference, but the point is: Go with iron or "electrical steel." 

Sean

[cinnanon]

It took Rhodes many years to work through these issues.
Look forward to hearing your progress in 2020:-)

The tine has come

[OZDOC]

Well, well, well
Have you had that in your diary all this time?
I wonder whether you'll get an update on progress?
David