KS 9: Bedding the Frontrail

KS 9: Bedding the Frontrail

So far, we have a clean keybed, an action with shanks off rest cushions and no excessive friction, screws not loose and no deal-breaking need for repairs, action return spring out, glidebolts off keybed (except hidden, height-establishing glidebolts, if present), cheekblocks bedded, and backrail validated. If we are lucky, the action has not needed to come apart. And if everything was in good shape, we are maybe 15 minutes into this morning's work. A lot of if's, you might think, but most under-30 pianos probably fit this category. And many deserve regulating, even when new.

Say a new baby grand has just emerged from its crate in perfect regulation (in which universe?). Already, gravity pulls it on its way to needing our services. Later, after a few years of gravity plus playing, the need for significant service is looming. And by the time it receives a full regulation, it will likely have spent much of its life underperforming. Here is a marketplace, and the demand, as piano owners find out what they're missing, who to turn to, and what to ask for, could be huge. 

But a host of variables makes us wary. Work by a previous technician (underdone or poorly done), debris and spillage, extreme conditions, athletic enthusiasts in one key, animal life, and general neglect - so many factors can complicate. At this time, the common expectation of customer and the trade is to treat the symptom and move on. And good preventative care is generally thought to be regular tunings and a Dampp-chaser.

To assess the need for a regulation that goes beyond touch-up, the frontrail is a first place to check (after key level, damper lift, pedal functions, letoff, backchecking, tone, and aftertouch...). In some actions, we can pop the keyslip off, with no screw removal, and tap. No symptom is what we hope for and that might support a lack of urgency.

What if there is a symptom? We tap and get a tap back. We will need to start our regulating to even know whether the frontrail is at fault. A slightly overextended glidebolt, for instance, from solving a balancerail symptom could be a culprit, but we'll have to back all glidebolts up to find out.

But that is why we're here ticking off this list. And if we were skillful, efficient, and thorough in these steps, the longer it has taken us, the more we were needed.

So now, prep done, action assembled and in position, hold down (as needed) first one end of the frontrail then the other and gently tap along its front edge. As with the backrail, any gaps will answer back.

To correct a frontrail gap, remove keys and topstack (they make the action too heavy for this work) and confirm symptoms with only the keyframe. Mark any gaps with chalk. Then, select appropriate widths of 220 sandpaper (again, coarser grits risk going too far and causing extra work) to relieve areas of contact until full contact is achieved. Fold a sheet of sandpaper lengthwise, place one side on a flat surface with the fold over a sharpish edge and tear. Use strips between keybed and frontrail, grit side up. You may need to ease the weight of the keyframe a little as you pull the sandpaper through. Sometimes placing a stationary sheet or other shim to the side of your target area can help. As with backrail fitting, take the least material away to eliminate the gap. And again, keep surfaces dusted and wear a mask.

When done, reassemble, validate, and move on the the balancerail. The foundation of our regulation is all-this-work important. Budget and time may constrain us to quicker fixes that will improve a situation, but we should encourage more good foundations, piano-by-piano, customer-by-customer. Tunings and the Dampp-chaser make a start. Then, we're allowed to speak up.

Next week: Bedding the Balancerail

(Index of all articles in this series)






Thanks, Jim.

Jim R Anderson

Thanks for these missives. I am enjoying your description of regulating prep.

Jim R Anderson

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