This is a multi-part message in MIME format. ---------------------- multipart/alternative attachment Robert, Firstly, I am not knocking the idea as it appears to be a vast = improvement on the original but, In an old PTG journal (about 20 years ago) there was an article with = photos about repairing cracks in iron frames. From memory, the method = used in that instant was very similar. Holes drilled and threaded and = screws inserted. The piano tuner who did this was from South Australia. = (thats the country down under) Can't remember his name but maybe some oldtimer who has got all the old = editions of the Journal on the list will remember the article and be = able to look it up. I have found through my years of working on pianos that many seemingly = new ideas and concepts have been done before, and we are now = rediscovering them. Regards Tony Caught caute@accessnt.com.au=20 -----Original Message----- From: Robert Goodale <Robert.Goodale@NAU.EDU> To: pianotech@ptg.org <pianotech@ptg.org> Date: Wednesday, 16 December 1998 3:33 Subject: EXTRA! EXTRA! Plate Repairs- THIS COULD BE IT! =20 =20 While at Yamaha an amazing new method for repairing cracked piano = was shared by another member of the group. This is a completely new = technique and is unlike anything previously discussed. This group = member also brought a video tape for show and tell which put everyone in = awe. Even LeRoy was dumbfounded and is now wanting more information.=20 This is no joke folks, read on...=20 This crack repair method was developed originally for repairing = cracked cast iron engine blocks and other heavy machinery. It involves = no welding whatsoever. Instead a series of very specially designed = screws are inserted into the crack which quite literally pull the crack = together stronger than it was before. When the repair is complete it is = almost invisable. This may sound to good to be true but the tape = demonstrates this clearly. Two flat pieces of cast iron were fastened = together in a butt joint by a single one of these screws, and was then = hooked on each end with a heavy chain. The chain was then connected to = a wench which lifted a 350 pound engine block. The bond held perfectly. = A complete series of pins overlapping in a crack seals the crack = permanently and stronger than it was originally. On bench tests these = repairs were shown to be completely air tight at 80 PSI.=20 Ok, so here's how it works. The screws are designed to dig in to = the cast iron. They must go into a pre-drilled hole using a special = bit. The holes are also taped. The secrete is in the screw threads which = are cupped sharply upward. The top half of the screw has a countersunk = collar which pulls tightly into the hole in the opposing direction of = the cupped threads. The screw is driven into the cast iron using an air = drill until the torque breaks of the head. The result is that the cast = iron is clamped tightly together *internally*. A series of these screws = are installed to follow the crack side by side. Then an overlapping = series of screws are inserted in a second pass. The remains of the = torqued-off heads are ground away smooth. No welding, no mess. This = type of repair can even be made inside the piano without plate removal. = There are several types of these special screws which can be used on = various types of cracks, even on angles or in corners. They are also = available in various lengths. The video presentation was extremely = convincing and had us talking about it for the remainder of the week.=20 This group member's local chapter recently decided to try this = repair as a joint project. The inventor of this technique was = personally present and assisted in explaining and then demonstrated the = repair. This proceedure is brand new and this was the first such repair = made on a piano. I think we can all pretty much expect to hear a lot = about this very soon.=20 This repair system is called the "CastMaster" by a company called = Lock-N-Stitch. They do have a web page. Check it out and be amazed.=20 Lock-N-Stitch=20 Follow the link to "Information about Cast Master". After you've = read the text and looked at the pics, go to the link that demonstrates = the complete repair.=20 Enjoy!=20 Rob Goodale, RPT=20 ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/c6/14/33/3b/attachment.htm ---------------------- multipart/alternative attachment--
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