Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Mason & Hamlin model BB - broken jacks

Hello to all,

Haven't been here in a while, happy to return!

I have a question for the techs out there who may have the same problem. I have a client with a Mason & Hamlin model BB circa 2004(WNG wooden action) where the jacks are breaking apart. This has happened to 6 different keys so far, and they always break in the same way, in the same place (where the 2 pieces of the jack meet, at the right angle for the bottom of the jack). After dealing with this issue a few times the store where it was purchased was notified, who then contacted M & H, but no solution ever came about.

I've succeeded in using TiteBond wood glue to get them back together, and the ones I've fixed seem to be holding up well. The way I see it at this point, the only solutions are to either glue each one when it breaks, or replace the parts proactively.

My question for the general consensus here is: Has anyone dealt with this same problem in these pianos? Is this a common problem with these actions, or is this a unique problem?

Just thought I might pick a few brains before I take any further steps. Thanks in advance.

Common sense dictates that if six have broken, it is reasonable to expect the others will, also. Unfortunately for your client, the Mason & Hamlin warranty is only five years. You will either have to repair the parts as they break, or convince the client to buy new whippens, unless the piano is warrantied by the dealer.

I am normally not a huge fan of using CA glue in piano actions, but I wonder if in a case like this, a drop of CA at the joint would act as a stabilizer and prevent further breakage? This could be done quickly without taking everything apart. I believe certain types or brands of CA are better for wood than others. Of course you need to be careful not to glue the jacks to the wippen. And if this fails, the glue joint may be contaminated and you won't be able to glue it with wood glue....

Question - how are the jacks breaking? Could there be too much after-touch, perhaps in a fortissimo blow? Are the front rail punchings soft enough that in a hard blow the jack gets jammed into the proximal side of the window? Would firmer front rail punchings make a difference?

I would suspect that the jacks were defective in assembly, unless the let-off was set too close to the strings.

I have run into this problem with old Steinways where the glue joint has failed, and regluing them works. Titebond should be fine.

I'm suspecting the design is causing the jacks to break. The jacks are made in two pieces, and fused together right at the bottom, where the right angle of the jack begins. Every one that has broken has split right where it's fused together, so I'm thinking the glue joints are weak. The piano is in a church, it's well regulated and cared for. It's used a few times a week, and I don't see any other signs of abuse or heavier than normal use.

That is correct, but Steinway has been making their jacks that way for way over 100 years, and they do not come apart every day. It is just the glue joint that is failing, so gluing them back should fix them.

Speaking of proactive,

It would not be expensive or too time consuming to replace just the jacks.

Except sourcing them.

I have replaced just jacks in the past ...

What is it you think has changed BDB?

I think you're on to something here. It's certainly worth checking. I service an older Steinway at a church and a couple of them have broken. Gluing them fixed it but a more experienced tech was saying the key dip should be checked so the jack doesn't get blocked against the window (as said above).

Replacing the jacks would be fairly easy, except that these are for wippens that may not be made any more, and the manufacturer is not responding.

Greetings,
Actually, if the let-off is too far from the strings, the joint will be stressed more. Lessening the let-off distance creates more room for the jack and less travel after escapement.
Regards,

When the hammer blocks against the string, that is hard on the joint. I guess the point is that the let-off should be set correctly.

I can't see it. If the jack is blocking against the string, it is possible that the tender is in the least contact with the let-off punching, which would be the least, if any, stress on the tender.

My impression is that the M&H warranty is at least 10 years as I own a BB from around 2007. So it seem like the warranty should still apply.

You are correct. I was not thinking right. However, there are other regulation issues that can put undue strain on the jack.

However, in this case, I think it is most likely just to be bad glue joints.

I have to believe this to be the most likely issue. Either too much aftertouch or too soft front rail punchings (Perhaps combined with a very heavy handed pianist.) Any string breakage, (Yet)?

Spot repair, when a single tender glue joint has failed, is a quick (but high-precision) CA, or yellow glue repair. You are obviously already experienced in it. If the glue up angle is not perfect, the let-off can be reset easily enough (within reason).

On the other hand, doing a full set involves testing each joint, actually hoping to break it, and regluing all 88 at the proper angle. The question then is whether to pull each whippen, depin each jack and use a small jig to insure that each jack is correct as the joint is reglued.

I think we agree that bad glue or bad glue application is the culprit. If it is bad throughout, then the component parts of each jack will probably come apart, so as to be properly reglued. Surely even stubborn individuals would be persuaded with the help of a 7-10 second burst in a normal microwave oven (after having been removed from the whippen assembly).

The big labor cost is your time for action disassembly, reassembly, and let-off work after the repairs, regardless of whether you repair or replace the tender/jacks. The time to repin each jack will be the same - new or old. The time to do the actual repairs to the tender/jacks won't be the biggest time/labor component.

If you elect to attempt repairs to all the tender/jacks while still intact in the action, you could break the ones which will easily break, gluing those with yellow glue, but on all the joints which won't fail for you, soak in two successive applications of CA thin . Taking the action stack off the keybed before you start, and putting it in an action cradle, will help immensely in keeping the glue flowing away from the center pin area and helping your nerves.

Ah, the choices of life!

This is my my opinion on it.

If the hammer is blocking on the string on a "harder blow," and/or, if the key dip is to great for whatever reason (possibly the biggest problem here) you are then forcing the jack tender (the lower part of the jack) apart by forcing it to move further than it is intended to go putting a tremendous amount of additional strain at the joint, thus snapping it off at the joint. It isn't necessarily that the glue joint is loose as much as it could be that the regulation isn't close enough for that particular piano. Of course, it could be a lack of glue too so check everything.

Regulating the jack in the window, setting it in the proper position front to back, side to side, up and down is important.

Regulation for that particular piano, according to the manual or not, will likely make a big difference in how many jacks break in the future. I use the manual only as a guide and nothing more. I will often times change it according to what feels best for that particular piano only.

On one of our Steinway B's at the college, about 20 years ago, the tenders started breaking, and often. We adjusted the key dip, giving it a little, not a lot, a little less dip, a tiny bit at a time until we found what was best for that piano. It hasn't broken jacks since. We also changed the jack height a tiny bit in the window too.

FWIW. Hope that helps.

Hmmmmmm...

Consensus????

Now I am really curious: Will it turn out to be simply a glue/manufacture-related problem, or will it turn out to be a stress-related problem brought on by a combination of too-early let-off and perhaps too great key dip which is forcing the jack tip to move too far in the window, breaking off the tenders as they are forced against the regulating buttons?

Or could it be even a little of BOTH?

Inquiring minds must know, but must wait to find out.