When the keyframe has been bedded on the bench to have the same shape it had in the piano, our strike samples will work. We took each of these with the weight of a WNG Dip Tool at the front of the key. We first blocked the sample hammers against their strings, then "let them off" with a slight hesitation to refine the location. Now, working the inverse on the bench, we adjust the "strings" (templates) to produce the same symptoms. When done, their bottom edges will be at strike relative to the action.

If using a one-template letoff rack, regulate section by section. For a Regulating Rack with its several templates, one setup will serve the entire regulation and provide all needed references by simply adjusting height.  It is also very stable.

Regulating Rack templates should slightly exceed the width of each section, leaving about an eighth of an inch between them (except for where two butt each other in a long tenor section). The overstrung scale slightly tilts bass strings up toward the tenor and tenor strings up at the same angle to a high point. Plate bow may also contribute to this incline. At the tenor apex, a second template at the new angle will minimize the error one long template would have produced.

As with other procedures, roughing in will help speed things up. Rough in rail and then template heights to the original hammerline. Typically this will be low from wear and compression of materials (we may have already raised it some to successfully bed and sample). Set the lower stop on each leg to contact the rail bracket from below and set the upper stops blow distance above the brackets. Now, all the way up will be strike and all the way down hammerline.

Raise the rail to the upper stops. Because the hammerline was low, the strike sample hammers should now block against the templates. Placing the WNG Dip Tool at the front of each sample key, loosen the appropriate thumb nut and pinch the template up until the hammer just lets off. The roughing in will have limited the seesaw effect on the other end of the template. But take a second pass to refine, producing the same hesitation as in the piano. This replication gains more accuracy than a number can achieve and frees the result from being influenced by bench shape.

Now that we have a foundation and set of targets that match those in the piano, our regulating will fit when returned from the bench.

Next week: Recording Spacing Scale and Strike Heights

(Index of all articles in this series)