This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Ron: =20 I=92d be curious to know (if it=92s not proprietary) how you altered the = rib scale design in order to produce longer sustain with smaller dynamic range. =20 David Love davidlovepianos@comcast.net=20 -----Original Message----- From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of Overs Pianos Sent: Wednesday, May 25, 2005 8:39 AM To: Pianotech Cc: Martin Cop Subject: First on-line images of the Overs-Kawai 200 grand piano =20 Hi all, =20 I've just come through a couple of busy months. The last couple weeks I've put in over 80 hours on tools per week, to get the Yamaha CF rebuild out the door for its first concert tomorrow. Before that, we've been building a new piano out of a Kawai KG5 case and plate, a commission from pianist Gerard Willems, the concert pianist who recorded the Beethoven piano works on the Stuart piano. The Overs-Kawai is for his home studio. We are prepared to build further examples of the Overs-Kawai 200 for FOB A$60,000 (plus 10% GST for local buyers). =20 I'm pleased with the outcome of this design exercise, as I wanted to create a piano with a long-ish sustain and a smaller dynamic range, to produce an instrument more suited to a smaller studio. I believe the power of our 225 piano is way too much for a small studio. I also wanted to produce a studio instrument with a more economical finish than the standard high gloss finish. After experimenting with a number of colour mixes I arrived at a dark green (somewhat darker than British racing green). A semi-gloss two pack polyurethane in the green was sprayed off the gun. =20 The new 200 cm piano also features an Overs action, two new struts from the plate to the belly rail (originally there were none), a large sound board cut-off and an I rib board. There is no treble cut-off in this piano since it originally had a relatively small sound board area out behind the bridge in the top treble bridge section. The bridges and scale are a new design, with a nominal bridge height of 34 mm and a width of 35 mm. All bridge caps are multi-laminated maple veneer glued up with West System. =20 Images can now be found at; =20 http://members.optusnet.com.au/ronovers/overskawai1.jpg =20 The sound board is made from solid sitka spruce and is fully rib crowned and supported. It is darker in colour because we haven't bleached it. The bass corner cutt-off is made from a hardwood-ply laminated sheet which has a softer rock maple veneer top and bottom. The inside surface of the outer rim was originally black, but the veneer underneath was undamaged and with quite a nice figure, so we stained it and finished it with acid cat lacquer at the same time as we sprayed the board top and bridges. One of the nice things I like about grands where the pin block is removable, is that you can respray the inner rim, sound board and action bay with a clear finish coating in the one operation. This approach allows us to avoid the typical 'straw-broom-finish' which pervades most action bays. I remain unconvinced of the alleged superior tuning stability of those designs in which the pin block and stretcher rail is built integral with the case. I really like the Kawai KG6 as a shell from which to build a decent small grand (especially the earlier examples with the oak rims and back beams). I believe these instruments, when rebuilt appropriately, will outclass a new S&S model B. =20 http://members.optusnet.com.au/ronovers/overskawai2.jpg =20 This image shows the treble string sections. There are no specific front duplex lengths in this design. Any noisy duplex segments get a couple of drops of glue along the duplex segment to detune the noise. The typical Kawai half-round-chromed rear stringing pillow has been substituted with a hardwood antarctic beech strip, which is profiled in thickness to achieve the desired downbearing settings (I prefer to set the downbearing by varying the stringing pillow height instead of varying the bridge height - this is because I want a certain bridge stiffness to avoid tonal 'dips' between the sound board ribs). The stringing pillows are covered with green felt to slightly dampen the back scale activity, without the need of a listing strip. The serial no. first section, "OK1", represents Overs-Kawai s/n 1, while the 662460 is the serial number of the original shell. =20 http://members.optusnet.com.au/ronovers/overskawai3.jpg =20 This image from the bent side shows the green outer finish a little lighter than it is. The camera flash washed the foreground a bit. The plate is close to original with the exception that the strut junction at the bass/treble break is re-profiled to improve its aesthetics, and the plate perimeter bolts and set bolts are all chromed dome nuts, similar to the Overs 225 pianos, with a Baldwin style plate mounting system. The capo bars received their usual re-profiling and hardening. Also notice that the strut between the agraffe and first capo section has been ground to allow bridge clearance. The higher 34 mm bridge, combined with the much smaller crown radius causes the bridges to sit much higher in the piano, particularly in the mid sections. The stringing pillow heights in the tenor sections are often as high as 10 mm. Ideally, a crown in the treble hitch plate would help the setup where high-crowned replacement sound boards are fitted. The original crown in the belly rail is removed, prior to fitting the sound board cutoff, to slightly reduce the final bridge height in the middle. =20 http://members.optusnet.com.au/ronovers/overskawai4.jpg =20 This image shows the new bass bridge design. The suspended bridge is now thankfully gone, and the speaking length of A1 is shortened by 20 mm to allow for a longer back scale. Similarly, the hitch pins for the singles have been moved back so that A1's hitch is as close as possible to the back of the plate. The original piano had an A1 free-backscale-segment length of only 85 mm. This new configuration yields a free length of 135 mm at A1. With the double looped german eyes, this piano is now producing a very acceptable low bass for a 200 cm piano. The bass cut-off can be seen meeting with the bass side about a foot (300 mm) back from the hinge cut-out. The darker wood moulding between the sound board and cut-off area is antarctic beech. The plate is fitted using the Baldwin style mounting system, so the visible hole in plate perimeter-flange is for accessing the plate height adjustment screw, prior to fitting the perimeter bolts. =20 http://members.optusnet.com.au/ronovers/overskawai5.jpg =20 Well that's it for the this piano for now. The lid and fall has to be sprayed with top coat yet. Should be all completed in a couple of weeks. =20 The Yamaha CF which we rebuilt for Dubbo Council went out on Tuesday. The sound board re-crowning was very successful. This piano now has lots of sound board crown and it sunk out no more than a standard new sound board during the stringing process. The re-whatevered instrument seems to have lost its characteristic Yamaha-CF-light-tone, with the modified board yielding a much darker tone. While the plate was re-installed into the case to the same height as original, the cast stringing pillows had to be packed up by around 5 mm to achieve the desired down bearing settings. This indicates that the crown of the restored board was considerably higher than when the piano was new. Notably, the tone in the killer octave area was most satisfactory. We used new CF3 hammers for this repair and I must say I'm totally struck on the quality of the Wurzen felt. Thank you Andr=E9 for bringing this hammer felt to our attention. The tonal balance over the compass of the piano was quite remarkably even, even before any voicing was undertaken. I've taken images of the re-crowning process, but they were taken with my conventional SLR camera. The Overs-Kawai images are the first digital images we've taken. I may post a report to the list regarding the re-crowning process once I get the images scanned. I predict that a lot more re-crowning jobs will be undertaken in instances where the panel is not split. =20 Ron O. =20 =20 --=20 OVERS PIANOS - SYDNEY Grand Piano Manufacturers _______________________ Web http://overspianos.com.au mailto:ron@overspianos.com.au _______________________ ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/97/3d/34/dd/attachment.htm ---------------------- multipart/alternative attachment--
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