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Piano Roll Repair Table
Piano Roll Repair Table
by John Phillips  (961218 MMDigest)

Figure 1.  The music roll is shown in its normal attitude as in the spoolbox 
of the pianola, so that repairs can be applied to the top side of the paper.

Yesterday I finished a project I've been thinking about for years and have been actually doing something about for several months.  It's a table for repairing 88n piano rolls.  It looks like a little wooden coffee table about 18" (45 cm) long with legs about 5" (12 cm) high.  It's a few cm wider than a piano roll and has a flat chipboard top with rounded ends.  There is a sheet metal housing screwed to each end of the table.  One end contains the spring loaded chuck and the drive chuck for a roll.  These were salvaged from a discarded spoolbox found on our local garbage tip by a friend.  (His find provided the impetus to get this project going.)  The housing at the other end contains the take-up spool from the same spoolbox.  Crank handles on the drive chuck shaft and the central shaft of the take-up spool enable the roll under repair to be moved back and forth.

So far this sounds like any old repair rig but wait, folks, there's more!

Figure 2.  A shallow groove in the brass bearing disk slides easily into the slot of the supporting 
panel.  The steel shaft rotates within the brass bearing.  Two small collars secured with setscrews 
prevent the bearing from sliding down the shaft when the assembly is transported.

Often, when repairing a roll, one comes across a section where some (supply your own adjective here) person has applied sticky tape to the underside of the paper, or where the paper is so badly folded and torn that access to the underside is necessary.  This outfit makes that possible; so far I've only described half of it.

The bearings for the shaft of the take-up spool are two brass disks, about an inch in diameter and a quarter of an inch thick.  The shaft fits through holes drilled in the centres of the disks.  Each disk has a shallow trough turned in the middle of its rim.

The sheet metal housing at the take-up end has two vertical U-shaped cutouts, into which the brass disks' shallow troughs just fit.  This means that the take-up spool can be lifted up out of the housing at any time. When I want to get at the underside of a roll I clip a second "coffee table" with shorter legs to the music roll end of the first table.  This second table has a metal housing with U-shaped slots at its far end.  All I have to do is lift the take-up spool out of its usual position, move it up and over in a wide arc and fit it into the second set of cutouts.  Hey presto!  The roll is now lying underside up on the second table surface.

Figure 3.  The unique feature is that the take-up spool is easily moved to the 
opposite end of the table, so that the underside of the roll becomes accessible.

Why does the second table have shorter legs than the first?  Because the paper is now unwinding from the bottom of the roll rather than the top.

Figure 4.  Now the underside of the paper is exposed for repairs.

Merry Christmas, everybody.

John Phillips
Thu, 19 Dec 1996 13:35:48 +1100

12 July 2000

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