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Re: Crow Foot Adjustment

Author: Chris P
Date: 2021-02-18 04:18

The crow's foot adjustment usually goes out when the RH F/C touchpiece gets bent down as it's a very easy and vulnerable key to bend because of its height, design and the hardness of the metal it's made from. Some are made from fairly hard metal like cupronickel (which Yamaha use) and others of much softer cast nickel silver alloys. The arm that joins the touchpiece to its barrel is relatively thin as it has to run over the top of the Ab/Eb touchpiece arm and that's usually its undoing.

To check the pads are seating, use a feeler gauge cut from the thinnest cigarette paper you can get, cut into a long wedge shape (without the glue line) with the narrow end around 2mm wide. Place the end between the pad and the tonehole and with gentle finger pressure to close the pad against the tonehole, draw out the cigarette paper and you should feel drag which means the pad is making contact with the tonehole.

Test the entire circumference of the pad this way and notice where there's more or less drag, or none at all as that will be where the pad isn't making contact against the tonehole. If the pad is too light on one side and too heavy on another, then the pad cup has either been bent if the pad was seating before, or the pad hasn't been seated correctly and that's a much easier fix if you know what you're doing.

You will also use the feeler gauge to check the regulation where one key closes another along with it - in this case the E/B key closing the F/C key and the amount of closing pressure each pad should have. Assuming all the pads are seating well, the E/B key pad should close with slightly less pressure than the F/C key pad as that will ensure you'll get E/B by holding down just the one key and it'll also take into account the torsion in the keywork - always expect there to be some torsion in the keywork.

Now the crow's foot adjustment - don't stick anything to the silencing material on the crow's foot if it's still intact as that will only infuriate your repairer if it's ended up a really sticky mess when the silencing material was already in good condition, but now needs to be replaced as that's turned a simple repair into a more involved one when keys have to be removed.

And assuming you've not stuck anything to the crow's foot in a bid to 'cure' the problem (and not causing any problems in not doing so), you can carefully bend the touchpiece back up by placing your left thumbnail under the crow's foot (between the crow's foot and the joint) and then gently and carefully bend the F/C pad cup down by applying pressure with your right thumb, a little at a time instead of one massive bend. Then check the closure of the F/C key pad with the feeler gauge when holding the E/B touchpiece down to close the pads with light finger pressure.

If the F/C pad is still not closing, then repeat the bendig process until it closes but with slightly more pressure than the E/B key pad. Always test it by holding down the E/B touchpiece or LH E/B lever rather than holding the E/B pad cup down as the amount of key flex (or torsion) will differ and you'll get a false reading.

If you've overdone the bending and the E/B key pad isn't closing at all using light finger pressure (and the F/C key pad is closing), then you'll have to gently bend the F/C key touchpiece down until you get both pads closing against their toneholes as they should - don't simply push the F/C key touchpuece down as that will compress the pad, but support the front edge of the pad cup with the edge of your thumbnail and then gently push down the touchpiece and test the pad closure with feeler gauges until both pads are closing as described earlier.

If you then find there's a gap between the crow's foot and the underside of the E/B touchpiece, but no gap between the crow's foot and the F#/C# touchpiece and there's no play/lost motion when using the LH F/C key, then you'll have to bend the linkage arm on the E/B key to close the gap completely. Hold the E/B touchpiece down and press down on the shorter linkage arm that links the E/B key to the LH E/B lever and check and repeat until the gap between the crow's foot and the RH E/B touchpiece has closed up. Don't overdo it as this is more difficult to reverse without damaging the silencing materials on the linkage arm as they're only small squares glued to a small surface area and easily compressed or torn off.

If you're in any doubt or don't want to take risks, then take it to a competent woodwind specialist as soon as you can. Better to have them put it right than doing anything that could cause harm and end up being an expensive repair instead of a relatively easy and less costly fix.

Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.

Post Edited (2021-02-18 20:49)

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