New grommets problems with sustain

Started by Dote, October 07, 2012, 04:26:43 AM

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Dote

Hi,

there was a thread in 2008 discussing sustain problems with ne grommets+screws, but I want to bring this up again and find out if more people do have this problem?

I recently bought a MK2 from early 1980. Played nicely upon arrival, great sustain, but the grommets were seriously squished on some tonebars and the side-to-side motion was bad, some tonebars even touched each other resulting in ringing sound. But nice sustain on the higher notes.

So I ordered a VV grommet+srew kit from a dealer here in Europe. After installing new grommets from note #73 down to #58 I found that the sustain on at least four notes was almost completely gone with the new grommets. I btw. also set the escapement to 3/8" (width of a tineblock) at the same time. (Btw: at least ten screws from the VV kit have a much smaller shoulder so that the grommets do not fit as tightly. I figure this is done to adress notes where you get loss of sustain with overly tight grommets.)

Putting back in the old screws and grommets got the sustain back on two notes, or putting in the VV screws with the smaller shoulder. Raising the escapement a bit helped on another note and touching the tonebarscrews with a screwdriver or blocking the tonebar to the rail with a tineblock (screwing down the tonebar while the 3/8" tineblock of a broken tine is placed at the end to set escapement).

I really do not know what to do now. Find old grommets that are not to squished and install them in these notes?

Not all the old grommets were hardened, some look surprisingly good.

Do I only exchange the old grommets showing serious deterioration and leave the rest alone?

Any ideas welcome!

Cheers,

Dote

Ben Bove

In many cases, because it's not an exact science sometimes playing around until you get it right is ok.  Best of the old grommets, new grommets, tonebar clips and whatnot - I often swap things out until it sounds right.
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Dote

Hi Ben,

thanks for the reply.

I got it fixed by using one of the springs of the VV tine stabilizer set in the "timbre adjustment" position.

Couple of observations:

Using only the rigid tine stabilizer spring on the middle tonebar screw (timbre adjustment) produced the best sustain, but side to side motion was really bad without the escapement screw in place. Maybe somebody should be looking into producing rubber stand-offs for the escapement side?

Using the original timbre spring on the escapement screw got nice sustain (albeit not as long as with only the tine stabilizer on the timbre side) and restored tightness with acceptable side to side motion.

I also tried using old grommets, but again if the sustain was great, side to side motion was really increased.

Oddly enough my MK1 did not have any of these problems using the much tighter fitting no name grommets and screws that had shoulders with threading.

Thanks again. Will post some pics of the MK2 soon.

Dominik

vortmaxx

A couple months ago I set about replacing some worn out looking grommets/screws when I acquired a 54 so I could give it a proper tuning and fix a few duff notes. The first thing I screwed up/learned is that when I put the first note back together I had reversed the spring configuration. I completely lost all sustain on that note. When I realized what I had done, I reversed the springs and the sustain came right back. Now, I always look twice and take pictures before I take anything apart. It definitely can make a difference which spring goes on which screw.