grand hinge to rim screws stripped

[John Delacour]

[ Two pictures included ]


At 19:44 -0400 3/9/08, Jessica Masse wrote:

>Besides drilling and plugging the rim, does anyone have a better way 
>of repairing the hinge screws on a grand piano?  This piano is moved 
>several times a year and the rim is less than 3/4 inch thick.

Here's how I always do it.  It might take 30 or 40 minutes but then 
the job is properly done and stronger than what was there originally. 
Stuffing things in the holes is just a way of delaying doing a proper 
job.

Line 1 shows a typical hinge rebate in a 19 mm rim.

If the rim has split, protect the surfaces and clamp it together 
before going ahead.  Leave on the clamp until everything is done and 
the glue has hardened.

Line 2 :  Plug the screw holes and trim the plugs flush.  The purpose 
of the plugging is to avoid interference from the screw holes when 
you come to drill out.  Mark points with an awl to centre the drill 
exactly in the middle of the rim, which is usually not where the 
screw line is.

Line 3 : Using a 12 mm. Forstner bit or similar (see illustration 
below) drill a line of 3 holes vertically to a depth slightly deeper 
than the length of the screws you will use.

Lines 3, 4 :  Using very sharp paring chisels, remove wood to create a mortice.

Line 5 :  Cut a piece of beech or rock maple to fit closely into the 
mortise. Apply epoxy enough to fill any gaps.  Press or hammer the 
piece into the mortise.

When the epoxy has set trim the plug to the original level, colour 
the repair and mark centres for the screws using the hinge as a 
pattern.  Drill for the screws using the appropriate drill for a very 
tight fit.  Lubricate the screws with a mixture of beeswax and tallow 
before turning them in.

This repair is as good as new and probably better, since the screws 
are now turned into solid wood of the densest and most suitable kind 
to hold them.

JD








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