2017 was our 20th year online!

Welcome to the Piano World Piano Forums
Over 3 million posts about pianos, digital pianos, and all types of keyboard instruments.
Over 100,000 members from around the world.
Join the World's Largest Community of Piano Lovers (it's free)
It's Fun to Play the Piano ... Please Pass It On!

Shop our online store for music lovers
SEARCH
Piano Forums & Piano World
(ad) Piano Sight Reading
train piano sight reading with your iPhone or iPad
(ad)
Best of Piano Buyer
 Best of Piano Buyer
(ad)
Pianoteq
Steinway Spiro Layering
(ad)
Wessell Nickel & Gross
PianoForAll
Who's Online Now
59 members (brdwyguy, AaronSF, chung_chang, butchkoch, clothearednincompo, 36251, BlizzardPiano, andrea monza, 10 invisible), 922 guests, and 513 robots.
Key: Admin, Global Mod, Mod
(ad)
Estonia Pianos
Estonia Pianos
Previous Thread
Next Thread
Print Thread
Hop To
Page 5 of 5 1 2 3 4 5
Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
Weight reduction for drilling one hole all the way thru two 3mm plates with 3mm holes already in it:

Code
5,0mm	0,59g
5,5mm	0,79g
6,0mm	1,00g
6,5mm	1,23g
7,0mm	1,48g
7,5mm	1,75g
8,0mm	2,04g
8,5mm	2,34g
9,0mm	2,67g
9,5mm	3,01g
10mm	3,37g 

(ad)
Piano & Music Accessories
piano accessories music gifts tuning and moving equipment
Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
Originally Posted by ambrozy
You didn't measure it like that? You just measured the weight of the whole hammer? if so, you have to tell which hammer weighed the 23.8g with the correct measurement method and subtract the difference from all the hammers

I did weigh the actual weight of the complete hammers, not the strike weight. Here are the corrected measurements for strikeweight:

----White-------------Black---(*gram)

1 - 26.1
2 ---------------------22.5
3 - 26.1
4 - 26.2
5 ---------------------22.5
6 - 25.9
7 ---------------------22.5
8 - 26.1
9 - 26.1
10 --------------------22.5
11 - 26.1
12 --------------------22.5
13 - 26.1
14 --------------------22.5
15 - 25.9
###################
16 - 24.8
17 --------------------21.3
18 - 24.8
19 --------------------21.3
20 - 24.8
21 - 24.7
22 --------------------21.3
23 - 24.8
24 --------------------21.3
25 - 24.9
26 --------------------21.3
27 - 24.7
28 - 24.9
29 --------------------21.2
30 - 24.8
31 --------------------21.4
32 - 24.8
###################
33 - 23.9
34 --------------------19.9
35 - 23.9
36 --------------------20.0
37 - 23.8
38 --------------------19.9
39 - 24.0
40 - 23.8
41 --------------------20.0
42 - 23.8
43 --------------------19.9
44 - 23.8
45 - 23.9
46 --------------------20.0
47 - 23.9
48 --------------------20.1
49 - 24.2
50 --------------------20.1
51 - 23.8
52 - 23.9
53 --------------------20.0
54 - 23.9
55 --------------------20.0
56 - 23.8
57 - 23.8
58 --------------------20.1
59 - 23.8
60 --------------------20.0
61 - 23.8
62 --------------------20.0
63 - 23.8
###################
64 - 21.3
65 --------------------17.5
66 - 21.2
67 --------------------17.5
68 - 21.2
69 - 21.2
70 --------------------17.6
71 - 21.2
72 --------------------17.5
73 - 21.2
74 --------------------17.6
75 - 21.3
76 - 21.1
77 --------------------17.6
78 - 21.3
79 --------------------17.5
80 - 21.2
81 - 21.2
82 --------------------17.5
83 - 21.2
84 --------------------17.5
85 - 21.3
86 --------------------17.5
87 - 21.2
88 - 21.4

Quote
And I suspect that that difference between white and black hammer weights are mostly to compensate for black keys being lighter on the front portion than white keys, so they have similar downweight on the end, if so, it's not technically correct way to do it

Do you mean the way Kawai made this is not technically correct, or the way we are planning to lighten the hammers would not be technically correct because of this?

Quote
Can you measure downweight and upweight of couple adjacent black and white keys to confirm that? and when you do this make sure that you measure in a spot that has the same keydip for black and whites

This seems not entirely possible as the keydip of the black keys is 11mm and the white keys is 12 mm.

But I measured 6 adjecent black and white keys (from middle c and up) and the down and upweight of the black and white keys seems to be exactly the same. Measuring untill the hammer reaches the let-off simulation rubber notch I get 65g downweight for both black and white keys. (If i take off a couple of grams it just results in the keys going down a tad less far) I get 50g upweight for both black and white keys.


Originally Posted by ambrozy
Those weight irregularities are negligibly small, I'd rather smooth those 4 sections but it also would be overkill in this case, so I think that making one additional section inbetween middle and treble section would be sufficient.

Your right. I made a mistake when I worried about the irregularities. I was thinking in grams, but of course the irregularites are just tenth of grams.


Originally Posted by ambrozy
so I think that making one additional section inbetween middle and treble section would be sufficient.
I see why you say that. The gap in weight between these sections is larger than the others. Probably not a bad idea!

Originally Posted by ambrozy
Weight reduction for drilling one hole all the way thru two 3mm plates with 3mm holes already in it:

Code
5,0mm	0,59g
5,5mm	0,79g
6,0mm	1,00g
6,5mm	1,23g
7,0mm	1,48g
7,5mm	1,75g
8,0mm	2,04g
8,5mm	2,34g
9,0mm	2,67g
9,5mm	3,01g
10mm	3,37g 

Great, thanks!

It seems doable to get the right ammount of weight off, especially since there also is space to drill a couple of extra holes in the plates if necessary.

Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
Originally Posted by U3piano
Do you mean the way Kawai made this is not technically correct, or the way we are planning to lighten the hammers would not be technically correct because of this?

They did this incorrectly, front of black key is lighter than white key, so for the same hammer weight you'll get higher downweight on black key. They reduced hammer weight of black keys so that downweight is the same for black and white and this is ok, but side effect of this is that moment of inertia is not the same for black and white, it should be done by weights in fronts of black keys. I'm not saying they have bad engineers, this decision was probably forced by some accountant who decided that installing weights in all black keys would be too expensive, so engineers had to find some other solution.

I put your data on chart so it's easier to see what's going on

[Linked Image]

Black hammers are on average 3.7 g lighter than white hammers, which is as much as we would like to take off. I see two solutions, leave it as it is and take off the same amount of weight from all hammers or take off 3,7g from only white hammers, and reduce downweight of black keys by weighting their fronts. We concluded earlier that weighting those keys would be hard without using standard lead weights, but I have one more idea, do something like they do in bass keys by screwing nuts under the keys with wood screws, one m6 nut weights 2,5g and small wood screw 1-2g, so two sets of two m6 nuts and wood screw screwed as close to front as possible should give 10g reduction of downweight for blacks. In the end you have to make decision what to do.

Quote
This seems not entirely possible as the keydip of the black keys is 11mm and the white keys is 12 mm.

There is a point on white key where key dip is 11mm, it's just not on the end of key but closer to pivot right? smile but I don't need any other measurements, I now understand situation well, the fact that they made different keydip in fronts of blacks and whites is understandable, they compensated short pivot length, I would design it similarly.

Last edited by ambrozy; 02/19/21 02:16 PM.
Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
Quote
They did this incorrectly, front of black key is lighter than white key, so for the same hammer weight you'll get higher downweight on black key. They reduced hammer weight of black keys so that downweight is the same for black and white and this is ok, but side effect of this is that moment of inertia is not the same for black and white, it should be done by weights in fronts of black keys. I'm not saying they have bad engineers, this decision was probably forced by some accountant who decided that installing weights in all black keys would be too expensive, so engineers had to find some other solution.

I see. learning alot here! smile

Quote
There is a point on white key where key dip is 11mm, it's just not on the end of key but closer to pivot right?

Ah yes, I understand it now.

Quote
Black hammers are on average 3.7 g lighter than white hammers, which is as much as we would like to take off. I see two solutions, leave it as it is and take off the same amount of weight from all hammers or take off 3,7g from only white hammers, and reduce downweight of black keys by weighting their fronts. We concluded earlier that weighting those keys would be hard without using standard lead weights, but I have one more idea, do something like they do in bass keys by screwing nuts under the keys with wood screws, one m6 nut weights 2,5g and small wood screw 1-2g, so two sets of two m6 nuts and wood screw screwed as close to front as possible should give 10g reduction of downweight for blacks. In the end you have to make decision what to do.

Interesting idea. While I would probably be happy with either option, I take it this would be the most ideal situation, so I will look into it and see if I think there's enough space underneath the black keys etc. Would this also mean adjusting the capstans to adjust the rest position of the black key hammers? Or should they stay the way they are? (which is not level with white key hammers)

What do you think is the reason these are higher in resting position anyway?

Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
Quote
What do you think is the reason these are higher in resting position anyway?
It looks like they reduced black keys keydip that way, it should rather be done by altering black keys leverage ratio. I'm guessing now, but blacks keydip was probably changed after production started and this was only way to do that. You can't correct this without altering key leverage ratio, so we have to leave it as is.

Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
You have to try that drilling because if I see correctly, these existing holes are there to keep the metal plates from rotating around, so you can probably only drill one hole.

Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
Originally Posted by ambrozy
Quote
What do you think is the reason these are higher in resting position anyway?
It looks like they reduced black keys keydip that way, it should rather be done by altering black keys leverage ratio. I'm guessing now, but blacks keydip was probably changed after production started and this was only way to do that. You can't correct this without altering key leverage ratio, so we have to leave it as is.

Aha. Well, leaving that as it is sounds good to me. That was the answer i was hoping for.

Originally Posted by ambrozy
You have to try that drilling because if I see correctly, these existing holes are there to keep the metal plates from rotating around, so you can probably only drill one hole.

I hate to say it, but your're absolutely right again. I didn't see it before, and I wondered why these holes were there, but I just noticed these holes are actually filled halfway by plastic notches designed to keep the metal plates from rotating around.

Anyway.. not touching these original "holes", I think I could get at least 4 extra holes per plate in, so that shouldn't be a problem.

I have asked a Kawai dealer what these hammers cost for the possiblity that things would go wrong. The answer was €16 per hammer. So all hammers would cost me about a new vpc-1, but as I try, of course I will see how it goes, and Ill only risk having to buy one or 2 new hammers. That said I don't really expect problems drilling a couple of small holes in them.

Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
It's been a while, but I'm back with some updates on the situation. smile

So, i'v been looking into everything described above, which is drilling the white key hammers to match their weight with the black key hammers, and then adding weigths to black keys to reduce their downweight. That and reducing keydip.

First, I reduced the keydip.

[Linked Image]

I put a strip of 1.2mm thick felt on top of the existing felt that's under the back of the keys, like you (ambrozy) explained, to raise the back of the keys a bit.

[Linked Image]

There was also a thin strip (about 1/1.5mm) of felt above the keys in the front, which I replaced with a 4mm felt strip to close the gap created by the lowering of the front of the keys. It's now a black strip instead of a red one, but I had this felt laying around and other than not being red it seemed perfect for this.

[Linked Image]

Keydip was about 13mm (white keys) and now it's about 10mm. (key on the picture could be pushed just a bit further down)

[Linked Image]

Then I went on to drill the last hammer (key 88) to see how that goes, and that wasn't too great. The steel is very hard and it's alot of hard work with a hand drill. Also, according to your calculations and my calculations based on that, I would need to drill 15 3mm holes per hammer (or 7.5 through both plates) to get 3.7g weight reduction. Thinking in 3mm holes and 52 white keys, that is 780 holes to drill in hard steel. shocked Of course I could drill maybe 5mm or even 6mm holes where possible but it will still be quite alot of drilling. By hand it seems impossible, for sure I would have to buy a drill press. That's not a big problem, but even with a drill press I'm not so convinced of this plan anymore. It's just too many holes to drill, and maybe or maybe not just enough room on the plates to drill these holes. Things could go wrong, I don't want the plates on the hammers to become lose or something like that. So, in the end, I think i will not continue with the idea.

[Linked Image]

That's how far I got with 5 minutes of hand drilling.

[Linked Image]

That's the result in weight reduction of that drilling attempt. The hammer was 26.8g, and now it is 26,7g. smirk

So, I think I will just see how the vpc-1 plays with just the keydip adjustement, but there is one thing that's still bugging me. That is the way Kawai dealed with the black keys being lighter at the front compared to the white keys. Like you explained, the way they "fixed" this, by reducing the black key hammer weight, this might result in comparable down and upweight in white and black keys, but like you said the moment of inertia is not the same. The black keys and black key hammers are lighter.

[Linked Image]

This is a picture I got from this pianoteq thread. Someone was also modificating his vpc-1, and stuck coins with strong tape to the side of a couple of hammers.

I could do that as well. What if I would add about 3.7g to the black hammers this way, to even them out with the white hammers, and then continue to apply your idea of adding weight to the black key fronts by adding 2 sets of m6 nuts? (about 10g) What do you think?

Joined: Mar 2021
Posts: 544
E
500 Post Club Member
Offline
500 Post Club Member
E
Joined: Mar 2021
Posts: 544
Wouldn't you have to recalculate inertia to re-balance the keys. where you drill would also make a difference.

Last edited by EinLudov; 05/23/21 10:17 AM.
Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
Those black keys hammers are a problem but it's a secondary problem, primary problem was downweight (and so balance weight and upweight) and adding weight to black hammers and keys is not resolving this primary problem, removing mass from white hammers and adding weight to front of black keys would resolve both problems. As I calculated earlier average inertia of this action is in reasonable range but static weighting is not, I would focus on that.

Originally Posted by EinLudov
Wouldn't you have to recalculate inertia to re-balance the keys.

Calculations were made.

Originally Posted by EinLudov
where you drill would also make a difference.

Yes but no, it's close enough (trust me I'm an engineer lol).

Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
Originally Posted by ambrozy
Those black keys hammers are a problem but it's a secondary problem, primary problem was downweight (and so balance weight and upweight) and adding weight to black hammers and keys is not resolving this primary problem, removing mass from white hammers and adding weight to front of black keys would resolve both problems. As I calculated earlier average inertia of this action is in reasonable range but static weighting is not, I would focus on that.


I do agree, the downweight was the primary problem. But since removing mass from the hammers doesn't seem as possible as I thought before, I guess the only good option left is to insert lead weights in the keys, I just have never done this before. Maybe I can get the right tools for this and practice a bit on a couple of pieces of wood to feel confident enough to do this. (i realize this will not reduce but rather increase inertia)

Also I wonder how it plays now with the keydip modification, which also decreases hammer blow distance, so ill probably put all keys and hammers back inside and play it for some time before proceeding with the above.

Or maybe ill get a drill press and try anyway... hmmm, decisions decisions.

Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
I don't want to be mean, but holes you drilled don't look good, they look like you have dull or low quality drillbit or wrong drilling technique, you definitely need drill press for this job, good drillbit and some cooling (wd40 will do) then work should be way more enjoyable smile

Joined: May 2015
Posts: 1,729
R
1000 Post Club Member
Offline
1000 Post Club Member
R
Joined: May 2015
Posts: 1,729
Originally Posted by U3piano
[Linked Image]

Is that "pin" or "rivet" passing through the nylon hammer and the two weights, between the two holes, made of steel?

If yes, perhaps drilling that out (or, pressing it out) and replacing it with an aluminum rivet might yield the weight reduction you seek?

Last edited by Ralphiano; 05/26/21 02:30 AM.

Ralph

Kawai VPC1
Garritan CFX
Pianist since April, 2015
Joined: May 2015
Posts: 1,729
R
1000 Post Club Member
Offline
1000 Post Club Member
R
Joined: May 2015
Posts: 1,729
The weight reduction calculation would be a little more complicated (you'd need to determine the radius of that curve), but, once done, you could use a bandsaw to cut off the tip of the hammer, removing the necessary amount of steel.

Whatever method you use to remove steel from the hammer, bear in mind that the nylon core of the hammer, along with any epoxy utilized to secure the weights, will be sensitive to heat. For instance, using a bandsaw to cut off the ends of the hammers would likely introduce less heat than using a grinder to remove that steel.


Ralph

Kawai VPC1
Garritan CFX
Pianist since April, 2015
Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
Originally Posted by ambrozy
I don't want to be mean, but holes you drilled don't look good, they look like you have dull or low quality drillbit or wrong drilling technique, you definitely need drill press for this job, good drillbit and some cooling (wd40 will do) then work should be way more enjoyable smile

It must be the drillbit then. grin But no, your not mean, it's probably just a correct observation!


Originally Posted by Ralphiano
The weight reduction calculation would be a little more complicated (you'd need to determine the radius of that curve), but, once done, you could use a bandsaw to cut off the tip of the hammer, removing the necessary amount of steel.

Whatever method you use to remove steel from the hammer, bear in mind that the nylon core of the hammer, along with any epoxy utilized to secure the weights, will be sensitive to heat. For instance, using a bandsaw to cut off the ends of the hammers would likely introduce less heat than using a grinder to remove that steel.

Hey great thinking Ralphiano! I didn't think any further than drilling holes yet. I have never used a bandsaw before, so i'd have to look into that, but maybe just using a grinder would actually work better than drilling holes. But you are right about the heat, that could possibly cause a problem. But i'd just have to be careful. One new hammer is about $16 so i can always try. If one goes well, all should go well.

I think the weight calculation won't be a problem because I won't have to calculate anything. Whatever tool i (probably) will use, ill just cut off pieces bit by bit and just put the hammer on a scale to see how much it weighs everytime i cut off a bit. Also I can look at the black key hammers to see about how much steel should be removed, since these obviously already have pieces "cut out", compared to the white key hammers.

Quote
Is that "pin" or "rivet" passing through the nylon hammer and the two weights, between the two holes, made of steel?

If yes, perhaps drilling that out (or, pressing it out) and replacing it with an aluminum rivet might yield the weight reduction you seek?

I suspect that wouldn't make much of a difference in weight.

Joined: Apr 2015
Posts: 306
A
Full Member
Offline
Full Member
A
Joined: Apr 2015
Posts: 306
Have you tried it with reduced keydip?

Joined: Dec 2018
Posts: 1,758
U
U3piano Offline OP
1000 Post Club Member
OP Offline
1000 Post Club Member
U
Joined: Dec 2018
Posts: 1,758
Originally Posted by ambrozy
Have you tried it with reduced keydip?

Not yet. I'm awaiting delivery of some products so i can polish the keypins. I wanted to have that done as well before putting it back together.

Page 5 of 5 1 2 3 4 5

Moderated by  Piano World 

Link Copied to Clipboard
(ad)
Faust Harrison Pianos
Faust Harrison 100+ Steinway pianos
(ad)
PianoDisc

PianoDisc
(ad)
Piano Life Saver - Dampp Chaser
Dampp Chaser Piano Life Saver
(ad)
Mason & Hamlin Pianos
New Topics - Multiple Forums
Steinway D for Apartment? Am I Crazy?
by Harpuia - 06/12/21 03:36 PM
Pianoteq Beginner Here - Bare Necessities?
by dusty1920 - 06/12/21 01:22 PM
OT ... Free grand piano to a deserving pianist
by Dave Horne - 06/12/21 01:11 PM
Old music books
by Del Vento - 06/12/21 11:54 AM
Download Sheet Music
Virtual Sheet Music - Classical Sheet Music Downloads
Forum Statistics
Forums42
Topics207,475
Posts3,103,064
Members101,794
Most Online15,252
Mar 21st, 2010
Please Support Our Advertisers

Faust Harrison 100+ Steinways

Dampp Chaser Piano Life Saver

 Best of Piano Buyer

PianoTeq Bechstein
Visit our online store for gifts for music lovers

Virtual Sheet Music - Classical Sheet Music Downloads



 
Help keep the forums up and running with a donation, any amount is appreciated!
Or by becoming a Subscribing member! Thank-you.
Donate   Subscribe
 
Our Piano Related Classified Ads
| Dealers | Tuners | Lessons | Movers | Restorations | Pianos For Sale | Sell Your Piano |

Advertise on Piano World
| Subscribe | Piano World | PianoSupplies.com | Advertise on Piano World |
| |Contact | Privacy | Legal | About Us | Site Map | Free Newsletter | MapleStreetMusicShop.com - Our store in Cornish Maine


© copyright 1997 - 2021 Piano World ® all rights reserved
No part of this site may be reproduced without prior written permission
Powered by UBB.threads™ PHP Forum Software 7.7.5