CAUT

  • 1.  hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 08:41

    List,

    I need to hang a set of hammers on a 47 year old Bosendorfer model 200. The hammers currently on this piano were not hung by the factory. It is a sloppy enough job that measuring angles off the current hammers is not a reliable way of determining the correct hammer boring angles for this piano.

    I have consulted with Bosendorfer, but they do not have the information. I have also reached out two of our most esteemed techs with extensive Bosendorfer experience. They provided boring angle schedules that are similar to each other, but not identical (varying as much as a degree or two). Unfortunately, neither of these techs could verify that the information they had was applicable to a model 200 made in 1975.

    So, after all of that set-up, my ask is this:

    Does anyone out there have hammer boring angle data for a 1972 Bosendorfer model 200?

    Thanks,

    Alan

     



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


  • 2.  RE: hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 10:26
    Hello Alan-

    A couple years ago we did a restoration with OEM factory parts on a Bösendorfer 200 from the 70's, but I think the mid-70's and the previous parts were all original. I don't necessarily copy the original boring angles and try to find the best compromise between the originals and the actual string grooves. If helpful, I will copy the angles I used for my new hammers below. 

    88-49  @  90°
    48-39  @  85°
    38-37  @  84°
    36-35  @  83°
    34-29  @  82°
    28-27  @  81°
    26-1    @  104°

    At the time I decided to recondition the whippens by replacing the cushion felt, repining and cleaning up the drop screw stop leathers.  I didn't know then that Bösendorfer has redesigned their whippens since the 70's and have abandoned those assist springs in favor of the steinway-style butterfly spring.   They are expensive, but I would certainly go that route with upgraded whippens to do it over. Current action screws also are much improved and easier to deal with, which no doubt you already know.  What hammers are you using anyway?  


    best,
    Dennis Johnson


    --
    Dennis Johnson, R.P.T.
    Piano Technician
    Music Dept.
    St. Olaf College





  • 3.  RE: hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 12:14
    Thanks for this, Dennis.

    FWIW, your first change from perpendicular (90o) is to 5o. That is quite different form the other Bos 200 scales that have come my way which start with 1o (or 89o, depending how you look at it) and progress in increments of one or at the most two degrees at a time. One of them went 1, 2, 3, 4, 5, 6, 7, 8, 10, with -10, -11 & -12 in the bass. The other went -11, -12, -13, -14 -15 in the bass and 1, 2, 3, 4, 5, 6, 7, 8 down into the tenor. Also, the deviation from 90o on both of the other scales start at notes 67 & 68, whereas yours starts at note 48. Communication from Bosendorfer does recommend matching the string angles as closely as possible, which sounds like what guided your effort. Like I said, FWIW.

    Curious to hear about your wippen retrofit, converting from the Schwander-style wips w/ assist springs to the Steinway-style without the assist springs. Other than extensive re-leading of the keys (necessitated by losing the assist springs), were there any other modifications you needed to do in order to accommodate the different design? Move capstans? Move wippen rail? Change let-off buttons? Something else?

    We are using Renner Blue Point hammers on this job. I have heard them on another Bos 200, and they sounded great. OEM hammers may have been preferable, but the extra expense was prohibitive given our budget. Even if the Blue Points are not quite as good as OEMs, they will be a vast improvement over the way too hard and too heavy hammers on this piano now (hammers which, I am told, were purchased from Bosendorfer some forty-years, but hung--on original shanks and flanges--by a less-than-expert hand).

    Thanks again for your input and sharing the experience!

    Alan

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



  • 4.  RE: hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 14:08


    Alan-

    Yeah, I noticed that jump between 48/49, but that what is written in my note book.  Admittedly, that's different than normal but I don't remember any of those details from the job.  I said I didn't update the whippens but probably would given another opportunity.  You are correct that would imply a significant re-balance of the whole system but I enjoy that anyway.  There would be quite a lot of room to work with, considering the original hammers are heavy and the keys had relatively little lead.  The job turned out nicely regardless and the piano is very well liked (we even used factory bass strings which were very expensive) but just saying.  I would absolutely replace those worthless old action screws and I think they're about $130. /set.   I just recently returned from the Bösendorfer factory on a selection trip and we purchased a new 280VC for the hall.  We're looking forward to that delivery in late summer sometime. 




    Dennis Johnson, R.P.T.
    Piano Technician
    Music Dept.
    St. Olaf College





  • 5.  RE: hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 14:45
    Dennis,

    Apologies for my misreading of your OP re: wippen replacement.

    Don't have my notes handy, but notes 48 & 49 may well be the notes on either side of the break between the tenor and the lower treble section. Could be a significant change in string angle there. Will let you know when I measure if it is on the piano we are working on.

    With regard to the action screws you recommend replacing, I think we have changed out the hammer flange screws on this piano, since one or two sheared off during normal handling (and they broke off shy of the surface of the hammer rail, and had to be excavated out, of course!). If memory serves, I got some suitable replacements from Jurgen at Pianoforte Supply. Did you get yours directly from Bosendorfer?

    I have yet to find another bass string maker whose strings sound quite like Bosendorfer's. No idea what, if anything, they do differently, but their bass strings do seem to have a distinctive sound. And the only way to get that is to put up the big bucks.

    Lastly, congrats on the acquisition of your 280VC (and factory trip)! I have heard nothing but glowing reports about that model.

    Alan






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



  • 6.  RE: hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 16:00
    Hi again-

    Yamaha parts can get you those sets for hammer flange rail direct from the factory, just be patient.  If you do the whippen rail they are the same as sold by Renner USA for the damper tray. The hammer rail screws are about 2mm longer, as I recall.  

    Cheers-
    d.

    ------------------------------
    Dennis Johnson, R.P.T.
    St. Olaf College
    Music Dept.
    Northfield, MN 55337
    sta2ned@stolaf.edu
    (507) 786-3587
    ------------------------------



  • 7.  RE: hammer boring angles needed for Bos 200 from 1972

    Posted 06-29-2019 10:43
    Place a protractor on the stretcher and hold a thread along the string.

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

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



  • 8.  RE: hammer boring angles needed for Bos 200 from 1972

    Registered Piano Technician
    Posted 06-29-2019 14:00
    Yes, Jon, matching the string angles as closely as possible is the goal. But where hammers are more severely angled and larger as well, in the bass and lower tenor, there are clearance issues to contend with. Rather than sort that out entirely on my own from scratch, I was hoping to save some time by mining the data and experience of others.

    Your input is always appreciated!

    Alan

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