Balancing keys

stopher · Post by **stopher** » 27 Oct 2008, 13:35

Have now re-bushed the keys on my ancient Chappell upright I need some advice on balancing them now

I had to take out all the felts and paper shims as it was completly rotten - moths and mice had been busy.

Chris

Post by **Barrie Heaton** » 27 Oct 2008, 18:12

What state is the back touch baize like and the fount touch washers

Did you take a key hight measurement at the bass and treble befor you started

Barrie,

stopher · Post by **stopher** » 27 Oct 2008, 18:34

The baize and washers were virtually non existent!

Erm, no, I didn't take a measurement!!!! School boy error looking back now!

Post by **vernon** » 27 Oct 2008, 23:05

Any chance of finding a bit of the original backtouch, a centre washer and a front baize. ?
If you can find sound bits it will save you a lot of heartache as you can fit new ones the same gauge saving pages of directions on this forum for subsequently setting the touch depth and key levelling

Make sure you get proper backtouch felt( it's very dense)
If you've got none of these I can't begin to explain how to do it from scratch.

pianotechman · Post by **pianotechman** » 28 Oct 2008, 03:05

Vernon's spot on with taking the original measurement of the key height! Oh well heigh ho, here we go. Start with the 'back rail' height, setting the felt thickness so as the key capstans are roughly almost starting to move the hammers off the rest.[the hammer blow distance should be about 45mm from the strings] Put your new middle rail felts on, and pack underneath the rail so as to give you 10mm of touch depth/key travell at the front of the keys. The centre rail is usually screwed to the key bed at four points along it's length and this is where the packing is. Make sure you don,t raise it so high that the keys hit the underside of the nameboard rail! You can then finally work out what thickness front baises/front rail packing you need to give you the correct touch depth. Fine key levelling is done with a long straight edge, and paper punchings under the individual centre rail felts. Good luck!

Post by **Barrie Heaton** » 28 Oct 2008, 09:21

stopher wrote:The baize and washers were virtually non existent!

Erm, no, I didn't take a measurement!!!! School boy error looking back now!

Clean out the keybed You will need to order a new backtouch baze go for 3 mm then loosen the screws on the key frame put the action in and a few test keys All the "As" then pack under the key frame at the back till the capstans are touching the heal of the whippen tighten the screws at the back.

Order some 1mm balance rail washers and some 4mm fount touch washers

You are looking to set the key to just below the key block hight pack under the balance rail tighten the screws on the balance

Do the lost motion for all the keys after you have set the blow to 47mm

Now level all the keys Sharps should be 12mm above the naturals

New set the depth of touch to 10mm again pack or remove for under the front rail

Now use paper washers to level the keys and get an even depth of touch

Have fun

the trick is to go round and round getting better each time

Barrie,

Post by **vernon** » 28 Oct 2008, 10:08

I fear we are leading this chap into deep water wherein he may drown.
We all know the above but- O Enquirer! Advising a beginner, I wouldn't touch the packing, rather get as near as you can with the original.
However, if you decide to pack ( or unpack the back rail) make sure you don't push out any of the original packing otherwise a headache will ensue as nothing will change. Note that veneer is often used for packing and HALF of this can inadvertently be disturbed leaving half behind and the rail inclined. Indeed, there may well be half packings fitted originally to correct slight inaccuaracies in the original keyframe.
Make sure you don't push a lurking pin or pile of gritty dust under the rail as this will have the same effect as packing..
his applies to the balance and front rail.
If this all goes haywire, someone will have to take the whole lot out and start from scratch

stopher · Post by **stopher** » 28 Oct 2008, 13:30

Thanks for the advice.

Luckily I didn't take the back rail out - all I have done is remove the keys all at once so I could re-bush and then removed all the paper washers, the bits of felt washers that were left plus the mouse nest and moth eggs.

I had to remove what was left of any felt/baise as it was completly bare in places.

Anyway, I'll try getting on with this as I'm on half term and I'll be in touch if/when I need help! Thanks again!

Chris

Post by **vernon** » 28 Oct 2008, 14:07

don't remove the backtouch unless completely eaten.
Urgently fina half decent balance washer and front baize as a pattern of the gauge as you won't know the proceedure from scratch.

Post by **Barrie Heaton** » 28 Oct 2008, 21:07

stopher wrote:Thanks for the advice.

Luckily I didn't take the back rail out - all I have done is remove the keys all at once so I could re-bush and then removed all the paper washers, the bits of felt washers that were left plus the mouse nest and moth eggs.

Chris

Mice and moths seem to come together one must attract the other

Only glue the first 15mm of the leading edge (the front bit) of the backtouch leave the back lose makes a quieter return. The other advantage if you don't want pack under the keyframe you can put strips of cloth under the trailing edge of the backtouch baize

Myself I always take out the keybed and remove all packing and start for new but.... 30 years However, I had to start somewhere

Most Chappells key hight is 21 mm from the slip rail to the top of the keytop you need to leave 2 -3mm of balance pin showing above the chase (balance bushing housing)

Enjoy

Barrie,

pianotechman · Post by **pianotechman** » 29 Oct 2008, 18:51

Come to think of it, did the ancient chappells have those little metal action support brackets attached to the key frame Barrie? [like on old Bechsteins] If so ,he's gonna have to put any packing needed under the backtouch felt as you say.

Post by **vernon** » 29 Oct 2008, 20:44

i can't remeber. If they have then to touch the backtouch packing is instant death. My best advice is to leave the back well alone, replace the backtouch with EXACTLY the same gauge felt( if it's not all in the bin or sustains some sort of life ,short of moths and meece) and work forward-centre first of course. Level the keys , then set the touch depth

Post by **vernon** » 29 Oct 2008, 20:45

level the keys before you fit any front baize washers

Post by **Barrie Heaton** » 29 Oct 2008, 22:26

pianotechman wrote:Come to think of it, did the ancient chappells have those little metal action support brackets attached to the key frame Barrie? [like on old Bechsteins] If so ,he's gonna have to put any packing needed under the backtouch felt as you say.

I believe they did on the verts but most O/U were fitted with the standard HB action

Barrie,