Hammer Felt Restoration and/or Reshaping

[velo-hobo]

I have three different Wurlitzers, and they all to some degree have worn/grooved hammer tips.  I am fine with the playability and sound of them as they are but I realize there could be some improvement to be gained here.

Vintage Vibe seems to advocate for reshaping with a dremel sander and then re-regulating.

In the 200/200A Service Manual, section 5D on the regulation procedure mentions reshaping hammers with a sandpaper file (similar to dremel, just done by hand), but also mentions "puffing" up the hammer crowns with a 75% methyl alcohol solution.

Has anyone tried this?  Haven't seen any info out there with regard to this technique.  I have dug through VV's youtube videos pretty extensively and never see them mention using alcohol on the hammers.

Just wondering because it seems less laborious than reshaping the felt and re-regulating the blow distance, let-off, etc. but I would love to hear others' thoughts before experimenting on my pianos.

[pianotuner steveo]

The wurli hammers are so tiny that I personally do not recommend filing or sanding any but the bass hammers. Adding alcohol will soften the tone, just as it does in acoustic pianos, but if you use too much, it can loosen the glue that holds the felt on. Using a dremel is very tricky, if you have never done it, I would say do not experiment on a wurli. It is very easy to destroy acoustic piano hammers with a dremel, I can only imagine what a wurli hammer would look like if a novice did this.

I would only practice on a junk unit first, but they are hard to come by.

What you can try that is very safe, would be use an emory board on some and see how it goes. NEVER file the highest treble hammers, you will wear down to the wood in a few seconds.

You can also fluff up the worn spot with needles,but again, I do not recommend doing this on such tiny, fragile hammers. I have only had to mess with the hammers on one or two old (120's) wurlis, and the results were not that much different. Considering how risky it is, I would say leave it alone.

[velo-hobo]

Interesting - Steve I did notice you recommended against dremel reshaping in a previous posting.  Obviously, Vintage Vibe are expert techs and can make a judgement about which hammers they can fix with a dremel and which need replacement, though it seems they endorse the idea pretty strongly with a caution here and there to be careful with removing too much material.

I could see using a hand file to reshape badly worn hammers that still have good felt underneath.  Using a dremel seems to be just a time saving way to get the same results.

What exactly is the difference in feel and tone from fresh or reshaped hammers?  Or rather, what effect does a grooved hammer have on the way a piano plays and sounds?

Also, regarding puffing up the hammers with alcohol, the manual recommends it for removing "click" from the strike.  In some cases I could see that being desirable, though maybe not always?

As an example, I once replaced a set of hammer tips on a Rhodes I used to have because many were badly grooved.  The result was that the tone of the piano changed completely - it no longer had an aggressive attack but sounded much mellower, due to the softer rubber of the new tips.  Cool, but not what I was hoping for.  Much like I never change the strings on my basses unless they break, sometimes a factory-fresh setup loses the character an instrument has acquired from years of use.

[pianotuner steveo]

 I am sorry, bur I have been working on pianos for 35 years and I would NEVER use a dremel on a Wurlitzer! too easy to make an irreversible mistake.

[SlowMonroe]

I just saw this-I agree with Steveo

Don't let ANYONE near your hammers with a dremel! Wurlitzer hammers are too small to reshape (with the exception of bass hammers, sometimes). It is a lazy and irresponsible thing to do to your instrument!