<div> This was just a normal screw type jack.  And maybe this had nothing to do with the plate cracking, but after stringing the piano, it was in a lot tighter then when I first put it in.  <font face="Arial, Helvetica, sans-serif">I had put it in just snug enough so that I couldn't move it.  </font>I guessed that the string tension pulled that corner of the plate and maybe the jack gave it that borderline amount of support(?)  Probably didn't have the plate in position as well as I thought.<br> <font face="Arial, Helvetica, sans-serif"><br> Anyway, the crack happened as I released the jack, so I'm thinking there is some connection.  It's about 5 hours since this happened, and the strings are still at pitch.  <br> <br> I don't consider myself a rebuilder.  This project was more of a change of pace for me (I'm primarily a field technician) and this particular instrument was a good one to screw up (if I had to screw up a piano!)  since it had little value to begin with.  I AM feeling gun shy, however.<br> <br> Gordon Large<br> </font></div> <div> <br> </div> <div> <br> </div> -----Original Message-----<br> From: Farrell <mfarrel2@tampabay.rr.com><br> To: Pianotech List <pianotech@ptg.org><br> Sent: Wed, 2 Apr 2008 3:35 pm<br> Subject: Re: cracked plate<br> <br> <div id="AOLMsgPart_2_cc75938c-3406-48ee-9548-16680cd647dd"> <div><font face="Arial">What Dale said.</font></div> <div><font face="Arial"></font> </div> <div><font face="Arial">Support jack? A pinblock support jack? I'm having trouble visualizing how a pinblock support jack could cause the plate to crack. You reference "releasing" the jack. What type of jack is it? I'm only familiar with screw-type pinblock supports.</font></div> <div><font face="Arial"></font> </div> <div><font face="Arial">When you put the pinblock support in place, I guess I've never been instructed one way or another, but I just snug it in - I don't jack the pinblock up at all. So if the jack didn't move the block, and hence the plate, and then you remove the support with tension on the strings, okay, so the plate/block will adjust some tiny little bit, but why would it cause a crack? Seems to me the plate would be in that position anyway and would be experiencing whatever stresses it does either way.</font></div> <div><font face="Arial"></font> </div> <div><font face="Arial">I just don't see how removing a pinblock support would cause the plate to crack. Thoughts?</font></div> <div><font face="Arial"></font> </div> <div><font face="Arial">Terry Farrell</font></div> <blockquote dir="ltr" style="border-left: 2px solid rgb(0, 0, 0); padding-right: 0px; padding-left: 5px; margin-left: 5px; margin-right: 0px;"> <div style="font-family: arial; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;">----- Original Message ----- </div>  Check the Archives for <a target="_blank" href="http://www.Lock-n-Stitch.com">www.Lock-n-Stitch.com</a>. Been lots on it<br>  Dale Erwin<br> <br> -----Original Message-----<br> <div><font face="Arial, Helvetica, sans-serif">I have a Chickering 1/4 grand in the shop with a hairline crack on the treble strut between the two capo sections.  This is right where a nose bolt passes through, so the crack extends from the top of the strut to about halfway through.  <br> <br> I'm sure it was my error that caused the crack.  (I restrung the piano, chipped it, and had it up to pitch before realizing that I still had my support jack in the high treble.  With all the string tension, it was really wedged in.  It was very difficult getting it to release and when I released the jack, I heard the crack.</font></div> <div><font face="Arial, Helvetica, sans-serif">SNIP<br> Gordon Large, RPT<br> </font></div> </blockquote></div>  <div id='u8CA631735BCBAC7-12D0-D1' class='aol_ad_footer'><FONT style="color: black; font: normal 10pt ARIAL, SAN-SERIF;"><HR style="MARGIN-TOP: 10px">Get the <A title="http://www.mapquest.com/toolbar?NCID=mpqmap00030000000003" href="http://www.mapquest.com/toolbar?NCID=mpqmap00030000000003" target="_blank">MapQuest Toolbar</A>, Maps, Traffic, Directions & More!</FONT> </div>