Posts tagged shimming
About six years ago i called a local double bass maker. I’m not up on my double bass makers… but apparently he’s known across north america for building some of the finest. I called him because i wanted some sitka spruce for repairing a soundboard on an old Bechstein grand piano i was working on. Because the piano was over 100 years of age, i wanted to put in cured spruce and not just ‘green’ lumber from the local hardware store. As well, ideally i would like clear grain wood – no wavy grain lines and no knots. When he answered the phone, we spoke for a bit and then he invited me to his workshop, an amazing place to say the least. After the small tour he queried me about how i was going to shim the soundboard. For those who don’t know, the soundboard is an actual board – like a giant sheet which acts as a resonator. But more than that, it’s the amplifier to the tone on the piano. They are pressure fit in the piano from the factory and quite frequently i’ll see cracks in those soundboards after decades. Ok… back to the bass man… he asked me “would you like to know how i repair cracks in guitars and basses?” “I’d love that”… i’m always up on learning new tricks of the trade. “OK so i open up the crack to about a millimeter or less (.039″) and i take a piece of the spruce and cut it slightly thicker than the crack. I then crush it in the vise – stripe each side with hide glue. After it dries i insert it into the crack until i’m happy with it. Then i take my steamer and shoot it with steam. The wood swells back up to normal size after being crushed and the glue re-amalgamtes simultaneously. It is then pressure fit back into the board. Trim excess and VOILA!” Wow… what a clever concept. So i decided to change my ways of putting 1/8″ pieces in – similar to Spurlock method and try this instead. I’m all excited and can hardly wait to try this method. BTW, his spruce was not only clear grain, but also 30 years old – a perfect fit for my old Bechstein. I get back to my shop – ready to give it a go and then it ocurred to me: double basses and guitars are about 1/8″ thick… piano soundboards are about 3/8″ thick. Problem: what sort of saw cuts through with any precision 3/8″ material? The hunt was on. I researched routers, jigsaws, gizmos and gadgets. Finally finally finally i came to this tool – called the Fein multimaster. It did EXACTLY what i wanted. A brilliant (and i might add fairly expensive) tool. And so i started this new method of shimming taught to me by my friend in the guitar world. Ok check out this picture – one grain thickness and absolutely straight.