Thanks mucho Alan, This is the info I'm looking for.  The capo to front bearing angle was large enough to file down a bit of the front bars and now file "up" a bit of the capo.  Just 0.5mm total or so, just enough to get some of the grooves off the bar and front bars.  The angles I think, now, might be closer to "ideal".  I think maybe the best resolve is to average the two schools of thought and shoot for a 1mm radius with a bit larger (0.02mm in the lower parts and a bit narrower( or just at 1.0mm) in the high end.  You reminded me of what Steve Brady taught me many years ago when I resurfaced a Bosey bar that was doing the same thing.  Thank you!! Hardening a capo iron is something I know nothing about, so I may have to just see what happens..This is a practice piano, so,.....I'm practicing!! :>) Thanks for your reply! Paul <table width=100%> <tr valign=top> <td width=40%>Alan McCoy <amccoy@mail.ewu.edu> Sent by: caut-bounces@ptg.org 09/10/2008 04:57 PM <table border> <tr valign=top> <td bgcolor=white> <div align=center>Please respond to College and University Technicians <caut@ptg.org></div></table> <td width=59%> <table width=100%> <tr valign=top> <td> <div align=right>To</div> <td>"College and University Technicians <caut@ptg.org>" <caut@ptg.org> <tr valign=top> <td> <div align=right>cc</div> <td> <tr valign=top> <td> <div align=right>Subject</div> <td>Re: [CAUT] Fw: capo bar reshaping</table> <table> <tr valign=top> <td> <td></table> </table> <tt>Hi Paul, The email came through the first time. But the issue is a can o worms. The proper shape of the capo depends on who you ask. If it is too pointy and not hard enough, you quickly get grooves, which gives the capo a too flat bearing surface. If it is too flat (as it is when grooves have been cut into an otherwise sharp profile) then you will probably have noise (string sizzle) at the capo. Also part of the puzzle is the angle between the string plane and the duplex segment up to the counterbearing. If it is shallow it won't cut grooves as quickly, but it may not terminate the string properly. If it is steep, there is a tendency for cutting grooves. So what you need is a decent counterbearing angle (anywhere from 12 deg to 20 deg though you'll get arguments aplenty about what's the best angle) and you can get away with a shallower angle if the counterbearing segment is shorter (long and shallow will often give duplex noise especially if the length of that segment happens to be harmonically related to the speaking length). Also you need the capo to be properly hardened. And it needs to be profiled to some radius. Talk to Ed McMorrow and he will advocate a very sharp (0.5mm radius, I think). While others will advocate more like 1.5mm (about 1/16"). Me? I use a Stewart MacDonald diamond fret file and file it to probably around 1 to 1.5mm radius. As a rebuilder (of sorts) and somewhat pragmatic I worry less about the capo itself and more about the counterbearing angle and length of duplex segment. That is really the only easily changeable part of the equation. I know that some will harden the capo, but I don't have that skill yet. But I do alter the front duplex when I think it will be some benefit. Just finished grinding off the counterbearing bars of the piano in my shop and will replace the bars with half-round brass. The angle won't change much at all, but the segments will be significantly shorter (less than 30mm my eyeballs tell me, though I haven't measured yet). Like I said, can o worms. Alan -- Alan McCoy, RPT Eastern Washington University amccoy@mail.ewu.edu 509-359-4627 509-999-9512 > From: Paul T Williams <pwilliams4@unlnotes.unl.edu> > Reply-To: "College and University Technicians <caut@ptg.org>" <caut@ptg.org> > Date: Wed, 10 Sep 2008 12:29:47 -0500 > To: <caut@ptg.org> > Subject: [CAUT] Fw: capo bar reshaping > > I'm not sure if this went through yesterday.  I'm trying again. > ----- Forwarded by Paul T Williams/Music/UNL/UNEBR on 09/10/2008 12:28 PM > ----- > > Paul T Williams/Music/UNL/UNEBR > 09/09/2008 01:23 PM > > To > caut@ptg.org > cc > > Subject > capo bar reshaping > > > > > > Hi List, > > I'm working on a plate from a 1926 Steinway M that had been breaking lots > of string along the capo.  Both sections broke about the same number of > strings per semester.  Upon pulling the plate and looking carefully at > both sections, the top section was really flat (plus grooved and crusty) > and the lower section was more pointed like we like, but way deeper > grooved (and just as crusty). So, my conclusion is that both too deep of > string groove and too flat a capo surface experience the same amount of > string breakage. > > Now, I can't remember the width of the "peak" of the capo, but seem to > think along the lines of 0.5mm-1.0mm (top to bottom of whole capo) > >  Is this a bit too sharp? Could someone please remind me the proper > "shape" before I begin filing?  Do all the string grooves need to be 100% > gone? > > Thanks for the input! > > Paul </tt>