Intro: Grand Regulating as Voicing Prep

Parts set up to work vertically and strings then mated to vertical hammers provide best preparation for voicing. The Grandwork System brings the specs of a grand piano's action cavity and strings onto the workbench for efficient and effective regulating.

In Dale Probst's words: "The Regulation Station brings grand action work out of the cave."

Bed and Sample

Make sure shanks are off rest cushions and samples have no excessive friction. Remove the action return spring and sand out any indentations in the keyframe. If the backrail or the frontrail has a bedding problem, follow the Grandwork Bedding Protocol. Otherwise, bed the balancerail using the WNG Keyframe Bedding Tool, pedal not depressed for now.

Next, employ Keysteps to sample bedding and use a WNG Dip Tool for weighted samples of strike (see the Grandwork Sampling Protocol). These will provide far more accurate setup references than traditional dip, blow, and letoff samples. When bedding and strike on the bench match those in the piano, the work you do on the bench will be as if you are doing it in the piano.

Set Up

On the workbench, fix action position, shim frontrail and backrail to be stable, and fine tune balancerail to the Keysteps. Set stops on the Regulating Rack  legs so all the way up will be strike and all the way down will be hammerline. Then, position its templates to represent string heights along the strike line, choosing best-sized templates for each section and securing them at strike using the weighted kissing samples. Now they are at strike, record the hammer spacing scale along the bottom edges and make a record of their heights with String Height Gauge or Underlevel.

Assisted by Gauge Keys, fully regulate at least one natural and one sharp to validate specs, parts, and materials. 

Then remove hammers and wippens to an Action Tray, storing screws in order along the edges. File flared hammers with the Hammer Filing Jig and adjust hammer flange and repetition lever friction as needed. Then, with parts back on, space hammers to the hammer spacing scale and wippens to the hammers.

Make Parts Work Vertically

Set up the Squaring Platform (see Grandwork Alignment Protocol), traveling shanks to vertical with the Shank Traveler and squaring hammers to vertical at strike with the Hammer Square (strike provided by the Regulating Rack). Finish by spacing hammers back to the hammer spacing scale (also provided by the Regulating Rack) and then gang-file the straight-bored hammers, supported at strike by the Squaring Platform.

For installing hammers, add Hammer Hanging Jig to Squaring Platform after traveling the shanks. Hang the new hammers at strike and square them to vertical as you go with the Hammer Square Lite.

For best results, use the Regulating Rack to measure strike heights to hammer center pins before boring hammers. Cut overall hammer lengths to these measurements and bore from the tails. This custom work ensures that all aspects of the regulation will work properly.

Level Keys and Regulate

Square, space, and level keys next (on the workbench). Keysteps, pre-set in the piano under notes 1 and 88, support the straightedge to level naturals on the bench. Add Rocke Sharp Leveling Blocks to 1 and 88 and choose from five heights ranging from 15/32" to 1/2" (12mm to 12.7mm). Then, use your Key Level Stick to level sharps and naturals in the same passes.

If needed, rough in any elements that are way out of spec (see the Regulation Protocol) and set dip to what your regulating samples indicated (to be refined later by aftertouch). Space backchecks and set naturals to check as high as possible without upswing tail-scraping. Set sharps to match naturals. And once backchecking height is correct, set spring tension.

Set jack-to-knuckle position, regulating to samples using an 18” ruler and under-lit by a Lighting Rail. Place the Regulating Rack, set at hammerline with lights plugged in, just back from hammer crowns and wink hammers to set repetition height. Then set hammerline, letoff, and drop (measured with Gauge Keys). And refine aftertouch, tweaking dip, backchecking, and drop.

Weigh Off

For some jobs, you are now done. But for others, you are ready to weigh off. This step adds further evenness to the action and further simplifies voicing. 

Using the Weighoff Kit, match downweight and upweight speeds for each key, choosing downweight and upweight combinations of a selected balance weight or consistent downweight. The Kit uses the pick-and-add approach, where a pairing weight added to the upweight makes the downweight. Pick the pairing weight off and the key should lift the upweight, returning the hammer to rest. Add it back on and the downweight should depress the key to letoff. Position one or more key weights (lead or copper) on top of the key so speeds of upweight and downweight match. Apart from being fast, matching speeds reveals frictional irregularities, slower indicating too much friction, faster, too little.

Then, proceed with a refinement pass of your regulation, fast and fun, a polishing of your work.

Return to Piano

Reinstall the action return spring, checking that its bearing surfaces are perpendicular and shimming with washers and balance punchings if they are not. 

Re-bed the balancerail, this time with pedal fully depressed.

Then, settle wire, pitch-raise, and mate strings to hammers. This string leveling optimizes damper function, so fine regulate the dampers next, followed by pedals and trapwork.


For piano technician (and customer), the results will likely exceed expectation. And achieving these results will grow a confidence to sell more jobs - and to sell them for better pay!

The Grandwork System reduces the experience needed to succeed at each step and its go-nogo methodology breeds both speed and accuracy. Win, win!!