Pro Tip 29: Filing Upright Hammers

Flat, or misshaped hammers can ruin the tone of a piano. Flat hammers can also cause strings to break! It’s very important to learn how to properly shape hammers and restore or maintain the voice of the piano. Hammers should only take minutes to reshape and not hours.
In the last video Jim demonstrated his efficient method of reshaping grand piano hammers, and here he continues with the topic by showing how to reshape upright hammers. Hammers are quickly sculpted, then carefully shaped taking 1/3 of the string marks off of each side, then they are refined and made to look like new.

[@staceybeadle6946]

Jim! It's so fun to watch you work! You are such a master at what you do and have helped so many of us!

[@RobKennedyEditor]

So good to see someone who cares about their craft.

[@davidbauguess]

Thank you Jim!

[@marcperarnau2491]

thanks jim

[@marshallsmith1366]

Thanks Jim. Will the hammer rest rail need to packed under the rail felt after doing this job. Could taking off too much hammer felt cause the piano to be out of spec.

[@jbuzz8853]

Thanks! If you use my method you’re leaving the middle 1/3 of the crown, and even at the end or the process, when mating hammers to strings, you’re only removing a tiny bit of felt from one or two of the string grooves. So no, this type of filing will not affect the actual, existing boring distance. (Note that the boring distance has changed before you even started due to wear) However, it will slightly change the weight, and since the hammer was misshapen in the first place you will need to ensure that regulation is optimal. Notice I said optimal and not “back to factory specs”. The dimensions as well as the weight of the hammer are different because of wear, so you must find a compromise of dip and blow that works to give you proper aftertouch. I try to never compromise let off.
In other methods felt is sometimes removed from off the very top of the crown in the effort to remove even layers of felt. The “layers” are already compromised if the hammer is quite worn, so the “layer” concept has no validity. And felt does not “grow back” so that is why I try to never remove that last 1/3 of the top of the crown. Hope this helps.