Just modified the the job. To be on the safe(er) side, I ended up using super strong GRADE 8 Hex head 5/16" bolts (Same diameter as factory screws) since flat heads w/cone shape under head were available only in grade 2! I then used small locking washers, and put the bolts from inside to back, using extra large 1 1/2' outer diameter 'Fender' washers. I also used a 1.5" spade bit to counter sink. I think it should hold up pretty well indeed. Thanks for all the help! ________________________________ Date: Mon, 29 Oct 2007 11:58:28 -0500 From: IFixPianos at yahoo.com To: pianotech at ptg.org; pianolover88 at hotmail.com Subject: Re: Upright pinblock question On 10/28/07, John Ross <jrpiano at win.eastlink.ca> wrote: Why don't you just get a piece of angle iron, then you would also have rigidity. The original lag bolts are normally close to the top, so I think angle iron would work. You might have to route an indent, so the lid will lie flat. John M. Ross Windsor, Nova Scotia, Canada jrpiano at win.eastlink.ca ----- Original Message ----- From: 'gordon stelter' <lclgcnp at yahoo.com> To: 'Pianotech List' <pianotech at ptg.org> Sent: Sunday, October 28, 2007 9:18 PM Subject: Re: Upright pinblock question > I put the bolts in from the front, but with a > BUNCH of fender washers under the nut on the back: > lest the nuts/washers get sucked into the wood. > ( Nobody should put an upright right against the wall, > anyway. ) > On a very rare and costly upright I may soon be > working on, I intend to have a 1/8 inch ( at least ) > steelplate made to stretch all the way across the > back, with holes drilled in it, for the bolts to go > through. Not very pretty, but the most stable, > long-lasting solution. ( Should help keep the back > from 'cupping', too! ) > > Peace, > G > > > > --- Willem Blees <wimblees at aol.com> wrote: > >> > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > Hi Terry, I have done the exact repair you are contemplating on the exact piano you are referring to. First of all, the reason it seperated is because Kohler & Cambell in their very wise woodworkers way made their back structure from spruce and glued the pinblock to it. Since spruce expands/contracts at a differing rate than maple it seperated at the glue joint! Surprise! Now to the fix, first of all you need PIPE clamps not c-clamps c-clamps will warp and not give you nearly the holding power that pipe clamps will, I know I've tried both! You can get Pony brand pipe clamps at any home center, get the 3/4' , you can also get the threaded pipe you'll need, I'd get 12' lengths, that's long enough for any old uprights you may want to bolt in the future. I have about 8 clamps but usually only have space for 6 of them. Place a clamp near each screw bore the screw hole and pinblock behind it all the way through, I use 1/2' carriage bolts about 1/2' longer than the thickness of back and plate, If there isn't room for 1/2' use 7/16' or if that's still too big then you have to use 3/8' but then go to the grade 5 hardened bolts, the standard grade 3/8' snap off way too easily. They come in half sizes to 6'. I use a large flat washer under the head of the bolt, one large enough for the square heade to fit through it but for the round lip to catch on it, in back, a small flat washer and a lock washer and nut in front against the plate. Snug them tight until the bolt tries to turn, If they turn too soon, put a clamp on them at an angle to hold it while you tighten. There is no need to lower tension since your clamps will maintain the hold that the screws did. You will need a good drill, a cordless won't do the job, something with at least 4 amps of power. A good metal bit and depending on how thick the back is, perhaps a longer auger bit to finish out the hole, lengthwise. As for glue, I've always just used Titebond since it serves more as a filler than anything else and mostly squeezes out anyway. The plus side of investing in the clamps is you can invest in longer lengths of pipe to use them for case repairs on pianos, bench repairs, wherever you need a clamp of whatever length you need since you can combine lengths of pipe w/couplers as well as get longer lengths. Mike -- Learn from yesterday, live for today, hope for tomorrow. The important thing is to not stop questioning.-- Albert Einstein Michael Magness Magness Piano Service 608-786-4404 www.IFixPianos.com email mike at ifixpianos.com ________________________________ Peek-a-boo FREE Tricks & Treats for You! 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