In general, plywood is well known to not hold screws very well. And that is likely because many common plywoods are made of relatively soft woods. Pinplanks/pinblocks made of Hard Maple or European Beech are in a completely different league than common plywood. Indeed, a bottom board made of pinblock material would hold a screw as well or better than any material out there. Cost and ease of machining would be limiting factors though. Terry Farrell On Feb 17, 2011, at 10:24 PM, Bruce Browning wrote: > Terry, > Why the concern for ply to hold a screw? Surely this is the basis > for tuning pins holding in pinplanks. > > > On 18 February 2011 11:51, Terry Farrell <mfarrel2 at tampabay.rr.com> > wrote: > I will be fabricating a new bottom board for a customer's vertical > piano (moisture/mold damage). Any opinions on the best material for > the job? > > I suppose some sort of plywood. I am using a hardwood veneered > gazillion-ply plywood for another project and am surprised at how > soft it is - I don't think that will be the best thing. My concern > is for screw holding. I don't know my plywood grades all that well. > I should think an exterior grade of ply made of yellow pine or > something similar with one side sanded (the inside side) would do > the job well. Is there a grade designation that specifies good hard > wood that will hold a screw well? > > Or should I just make it out of a couple pieces of edge-glued (some > sort of water-proof glue) hard maple? I have tons of that in my shop > - I would have to make a trip to the lumber yard for plywood. > > Comments? Suggestions? > > Thanks! > > Terry Farrell > > > > -- > Bruce Browning > The Piano Tuner -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech.php/attachments/20110218/d103fedb/attachment.htm>
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