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TouchRail Touch Weight Measurements



                                           Touch Weight Measurements

                            BEFORE                                                             AFTER
  80                                                                   80

  70                                                                   70
  50                                              rest down weight                                                         TR rest down
                                                                       50                                                  weight
                                                                       40                                                  TR up weight
  30                                              up weight

  10                                                                   20

   0                                                                   10

The left chart shows down weight and up weight measurements for the bass section of a mid 70’s vintage Steinway model M. After traditional regulation
and lubrication, this action remained heavy, despite having 5 leads in each key . The right chart shows the same action after installation of a TouchRail
with down weight measurements readjusted to 52 grams. The TouchRail produces a lighter, more consistent touch response

more data
                  TouchRail versus Supplemental Lead Weights

75                                                            This graph shows how the TouchRail compares with added
                           10 gram down weight reduction      lead weights when reducing down weight by 10 grams. Key
65                                                            resistance has been measured at several points along the
                                                              keystroke. From left to right, each line includes:
55                                                                    1. Rest position down weight
                                                                      2. Down weight just before escapement
45                                                                    3. Low key return force *
                                               TouchRail              4. Up weight
                                               10 gram
                                                              The dotted line is the original key. The Black line shows the
                                               lead weights
                                                              same key with added lead weights. The green line shows
                                               10 gram
                                               reduction      the original key with added TouchRail (no added leads). In
                                                              the two lower lines, initial down weight drops equally by 10
                                                              grams. But as the key travels downward, (moving from
                                                              left to right in the graph) the TouchRail preserves
                                                              important low key measurements. The TouchRail key
      rest    depressed   low key   upweight
     down       down       return                             feels lighter than the original, and more responsive than
     weight    weight                                         the lead loaded key.

                                                              *low key return force = maximum weight that a fully
                                                              depressed key can lift to restore its mechanical repetition
more data                                                     function. Low key return force differs from conventional
                                                              “up weight” in that it is measured from the fully
                                                              depressed key position with the hammer unchecked .
     New Opportunities for Reduced Inertia, Improved Repetition

                                               Photos on the left hand side show a
                                               conventional action with down weight of
                                               49 grams. Below is the same key with
                                               lead weights progressively removed and a
                                               TouchRail added to restore the original 49
                                               gram down weight. Top right photo
                                               shows the removed lead weights, totaling
                                               51 grams.

                                               In the graph, down weight (blue), remains
                                               constant (49 grams) as a result of the
                                               TouchRail offsetting the reduced lead
                                               weights. The green line shows a dramatic
                                               increase in low key return force*.

                                               The TouchRail- assisted key retains
                                               progressively (up to 20%) more low key
                                               return force than the lead weight key.


                                               1. Key lead removal in new pianos can
more data                                      alter the warranty.

                                               2. Lead is toxic. Use caution when
                                               handling key leads.
This photo shows a repeated cycle test in progress. The sprung
oscillating paddle, driven by a drill press, is compressing a fixed
TouchRail spring 5 mm at each cycle. After 100,000 cycles, the spring
length remained unchanged. The position of the spring within the
TouchRail body was also unchanged. The TouchRail design remains
stable after extended use.

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