Key Height Regulation Methods & Tools

By Hannah Beckett

There are many techniques that can be used for setting key height during a regulation. As usual with piano technology, the best procedure will depend on your work style, body type, and regulation rhythms; there is no “one size fits all” for this part of the regulation process. That being said, this article details the method I have adopted, for reasons I’ll share along the way. My method is the same for vertical and grand regulations, but there are of course a few additional steps to take with grands.

Punching Set: Keep your punchings organized with this disaster-free punchings box. It's completely sealed, portable, and holds plenty of punchings for a full regulation. Available in The Collection.

WNG Key Leveling Stick

While small straight edges have their convenience, do not underestimate the value of a full-length straight edge. The ability to observe all the keys at once gives you valuable insight into the overall condition of the piano. There are many straight edges out there, but I recommend the WNG key leveling stick. It is durable, versatile, and of extremely high quality. It includes a crowned side for Steinways as well as the standard straight edge. My only caveat is to be cautious when using it; because it is made of aluminum, the edges are quite sharp, and one hasty move could leave a big scratch on any number of nearby piano parts.

Pianosmiths Sharp Gauge

I’ve tried many tools for black key height regulation but this one is by far the best! It’s extremely lightweight, hands-free, and allows for individual and consistent height-setting. It includes four different common specifications: 11.5, 12, 12.5, and 13mms. Available on The Collection.

The best way to become proficient in setting key height is to start on an upright piano.

Before you begin, observe the keys in relation to case parts. If you haven’t already read Setting Key Height to Case Parts, you may want to pause and read that before continuing. Setting a key height that does not take case parts into consideration can have disastrous consequences that you are likely to miss until you finish the regulation and try to reassemble the piano. A full re-regulation is the only fix for this mistake. It’s a painful lesson to learn - take it from someone who knows!

With the cheek blocks and fallboard installed, measure the current height of keys at the lowest bass and highest treble. Remove the front rail punching, and set stop blocks under sample naturals.

The weight of the straight edge is supported by these keys, and their key height can be transferred to the middle of the keyboard under the leveling stick.

Once you have verified that your desired key height will function with the case parts, you can start adding punchings.

Sit in front of the keybed so that your eye is level with the top of the keys (if possible, of course). Starting with the largest gaps, observe the size between the key and the straight edge. Estimating the correct size punching to fill the gap will take time and visual training, but soon you’ll be able to recognize the differences between a gap that can be filled with a .003 punching versus a gap that can be filled with a .005 punching. A general rule of thumb is that if you pair two of the same size punchings together and can easily slip them between the key and the straight edge, then one of that size punching is the correct size. However, ratios from the pivot point (the balance rail pin) to the front of the key will change with key length. A .005 punching is going to have a different outcome on a 44” upright with very short keys versus a 7’ grand with very long keys.

Slip all the punchings for the white keys under the straight edge. When you are finished, carefully remove the straight edge, being careful not to knock any punchings off of the keys. This is easy to do, and very annoying when it happens. A safer method is to put the punchings on the balance rail pins of the corresponding keys for safety.

Insert the paper punchings under the felt punchings. Craftsmanship standards call for thick punchings on the bottom, with the thinner ones stacked on top. I highly recommend a pair of forceps for this process.

When you are finished, check your work again with the straight edge. On your first few attempts, expect to do this process 4-5 times before achieving level keys. Over time, you’ll get this process down to one or two passes.

Pro tip: Take your time with key height. This is a critical part of the regulation, and it is far better to move slowly at this point and rush other points than to be sloppy with this core step.

Use the black key height tool to do the same process on the black keys. Always do the white keys first - black key height is relative to the white keys.

To ensure that you have not accidentally raised a key higher than its neighbors, very slowly lift the weight of the straight edge off the keys and watch for movement at the hammer line or wippens. If a key has been set too high, then its corresponding hammer will likely move in response to the weight of the level... but don't forget to move slowly with the straight edge so you don't scratch your key tops!

The method is the same for grand regulation; however, you’ll have to remove and reinstall the stack between each pass, which calls for extra caution to leave the punchings undisturbed. Before I pull the action from the keybed, I take a picture of the punchings on their keys so that I can quickly recreate my work in the event that a mishap occurs.

Again, placing the punchings on the corresponding balance rail pins is a safer option. I also recommend wearing an apron during the regulation process. It is handy for tool storage, but it also ensures that loose clothing won’t brush punchings off the keys!

As always, use best practice methods when removing the stack, and try to be as precise as you can with the first pass so you can minimize removal and reinstallation of the stack as much as possible.

Pro Tip: Steinways have rounded balance rail bearings instead of flat felt punchings. Keep these bearings facing the right direction by putting a small mark on the front of the bearing.

An alternative grand key height method is to purchase a set of grand key leads from Schaff (product #973). After removing the stack, you can place the key leads on the backchecks to simulate the weight of the action. Regulation can be done without multiple removals of the stack. However, I find this process to be slightly less precise than the former method. The only time I would recommend this method is if for some reason you must wholesale lower keys. In that case, the leads can save a significant amount of time and get you to the refinement process much sooner than multiple removals of the stack.