Pianotech

  • 1.  Stripped screw holes in lids

    Registered Piano Technician
    Posted 10-22-2021 08:33

    Greetings,

    Two situations in which the holes of screws that fasten things to their respective lids have stripped out. One is a lid indexing pin (is that the correct term for the male part in the lid that drops into the female part that is attached to the inside of the outer rim at the treble end?). That is on a Bosendorfer. The other striped screw holes are for the lock bar screw holes--yes, ALL of them--on a Steinway.

    Have yet to figure out how the lid index screw holes stripped out on the Bosie. There is no sign of any impact on the lid that would have stressed these connectors. As the young people say, "Whatever."

    On the Steinway lock bar, the holes were apparently stripped out by people repeatedly closing the front lid by grabbing the lock bar, rather than the front lid itself. It looks like the screws gradually loosened and eventually stripped out their holes. To add to the challenge, some of the screws are missing, and Steinway no longer provides the 2 1/4" long, #14 flat-head slotted wood screws for the lock bar of this 32 year old model B. Unless I can locate some of those screws from a third party, it would appear that I have no alternative but to go ahead and violate the Steinway-ed-ness of this instrument by using non-OEM screws. (Hey, at least I tried!)

    These are the options I have come up with so far for recreating holes that will anchor the screws in question:

    1) drill out, and plug with wood

    2) use wood putty

    3) use leather and wood glue

    4) use paper towel and thin CA glue

    If the stripped holes were in were a beefier piece of wood, I would plug them. But due to the relative thinness of the lids, that approach could be tricky.

    If you have successfully done this kind of repair, please share how you accomplished it. Idle speculation could also prove useful.

    Also, if you happen to have any of the OEM screws for the 32 year-old Steinway B lock bar (as described above), I would be interested in acquiring them from you. 

    Thanks,

    Alan

     



    ------------------------------
    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
    ------------------------------


  • 2.  RE: Stripped screw holes in lids

    Posted 10-22-2021 08:56
    Plug the holes at each end, and trim flush when dry. Position the bar with two other screws making sure it clears the case and the lock engages. Reposition if needed.
    Drill for screws on the plugged holes. Remove the bar and clear the wood chips. Plug and trim the other holes. Reinstall the bar with the end screw holes, making sure it clears the case and the lock engages. Drill for the other screws, remove bar to remove wood chips. Reinstall lock bar, making sure it clears the case and the lock engages.

    Make sure the lock bar clears the case and the lock engage. I had to do this on a 'restored' B. When I removed the lock bar (it was rubbing on the treble inside case), there were many screw holes from previous unsuccessful attempts. The trapwork didn't align with the pedal rods either. And the action played like a truck. Par for the course.
    Everything is OK now.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
    ------------------------------



  • 3.  RE: Stripped screw holes in lids

    Registered Piano Technician
    Posted 10-22-2021 09:34
    I can only made that it would probably be wise to make your own plugs (not from end grain) to do your plugging. That way you are drilling into new wood much the same as what was there originally (not simply a piece of end grain dowel). 

    Also, once the holes have been threaded you can grind readily available 2 1/2" screws to 2 1/4" to make up for the missing ones. 

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 4.  RE: Stripped screw holes in lids

    Posted 10-22-2021 15:14
    I mostly don's plug with wood any more, at least in the shop. I fill the hole with west system 105 resin and fast hardener, without adding any fillers. It takes a day to harden, but I am much more comfortable asking these holes to take serious load this way. \

    I do the same with the foot screws where action frames get screwed to the keyframe. Fill the hole with the 105/+hardener with no fillers and redrill. If you leave the filled hole so there is a little dimple where the epoxy soaks down a bit, you can find your hole location very easily. 

    By the way, huge turbines on wind mill generators, according to West system techs, use the same recipe, straight 105 resin/hardener, no fillers.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 5.  RE: Stripped screw holes in lids

    Registered Piano Technician
    Posted 10-22-2021 15:43
    Jim, can one assume that you don't drill out the hole the way one would do for a plug, but simply fill the old screw hole?

    You say you mostly don't, under what circumstances do you still use plugs?

    Tnks.

    ------------------------------
    Steven Rosenthal
    Honolulu HI
    808-521-7129
    ------------------------------



  • 6.  RE: Stripped screw holes in lids

    Posted 10-22-2021 21:07
    It is useful to drill out the hole to new wood...not much, but just enough to get some fresh fibers.  

    Last time I used a plug, I think was when the movers were coming in 15 minutes. I had put the cheek blocks in and out a million times on this Knabe grand. However I never bothered to screw them in. So, there I was, with fifteen minutes before D-day, and just realized the cheek block holes were stripped. I ditched my usual leisurely pace and became Flash Gorden for those fifteen minutes...sheesh...the whirlwind was frightening  

    I am a shop rat, so I don't need to triage much.

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 7.  RE: Stripped screw holes in lids

    Member
    Posted 10-23-2021 11:42
    In Dale's shop I was given the task of the tiny screws on the music rack hinges.
    I happened to have an epoxy filler,, some quick setting wood colored. Probably not as strong as West systems.
    It says epoxy is threadable so with West systems it has the compressive strength of steel. You don't put wood screws into steel unless you over drill the hole or use brass screws and then it's not perfect.
    After taking the class "More Bang for your Buck" Guy Nichols,,,, he said putting wood in a hole without glue is like pouring sawdust in the hole. I always used glue after that.
    My plan;
    I put the screws in some McLube dry lube and mold release.
    Then I got some toothpicks and mixed the epoxy.
    Taking the toothpick, I dipped the end in epoxy, put it in the hole and broke it off. I could only use the tip because these screws are so small.
    When all the holes were done, I assembled the music desk. The toothpicks held the screws snug.
    Watching the sample epoxy, I waited until it had set hard and with good pressure, the correct screwdriver,, the screws gave a little snap as they broke loose.
    Perfect,, a threaded wood screw hole. Just the drop on the end of the screw filled the holes with no overrun.
    Dale tried too,,, it worked for him. It's a little touchy removing the screws.

    I think wax would work better on large screws. I just used some wax on a jack that split through the adjustment screw. The screw turned really smooth.Even if the hole doesn't get completely filled, some is plenty.





  • 8.  RE: Stripped screw holes in lids

    Registered Piano Technician
    Posted 10-23-2021 13:24
    I use BSI's IC-2000 which is a thick black CA. I swab it in the hole with a toothpick, and let it set (or if in a hurry shoot it with accelerator) and screw in the screw. Very fast and very strong. If the hole is so bad that one swab don't work I do it again. Usually that's plenty. 

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 9.  RE: Stripped screw holes in lids

    Registered Piano Technician
    Posted 10-22-2021 20:07
    But SS doesn't use epoxy. Non-genuine part substitution. I'm reporting you to SS.  

    πŸ˜πŸ˜Šβ˜ΊπŸ˜‰

    Pwg

    ------------------------------
    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
    ------------------------------



  • 10.  RE: Stripped screw holes in lids

    Registered Piano Technician
    Posted 10-23-2021 22:08
    A great quick fix for stripped continuous hinge screws is a short piece of thin solder inserted in the hole.
    When refinishing I always replace screws with new screws slightly longer than originals after buffing or re-plating hardware.

    Sent from my iPhone