Posted 28 October 2003 - 03:32 PM
How many people make, or know how to make pads??
what grade of 'card'?
what grade, and nature, thickness of felt?
What grade and variety, thickness of leather?
what form of adhesive, or contact medium?
Or is it one of life' big trade secret(s)...?
Posted 28 October 2003 - 04:14 PM
Posted 29 October 2003 - 04:24 AM
- usually too hard or becoming too hard from ageing
- resulting in being too loud and causing rattle
- too flabby due to the unstable fixation causing jamming problems
- having too little thickness tolerance due to little available vertical space
....some of these problems not related to the pads only but to the unnecessary small tolerances of particularly treble englishes and small duets.
What do you want from them?
- tightness AND smooth silent and safe action.
- durability?...depends..it is fairly easy to make and change pads so if they last 2 years or 20 is not always a major issue.
- lightness? I haven't really thought of it but it might matter within extremes
I found it difficult to get them smooth and silent without making them thicker as well. You may go two ways...either a thick 'cushion' piece and a thin cover or a thinner cushion and a thicker and softer cover.
The 'traditional' cushion material seems to be varying types of cashmere felt, a kind used in piano mechanism for instance. It does work as known, compresses and becomes too hard after some (sometimes fairly long..) time. I never got the (in my view) ideal composition so I skipped it early and have ever since (25 years now) used some types of foam rubber sheet 2-4mm thickness combining with
leather from 'thinnest available' ( 0,15mm) up to 1.2mm ..'inside' out with tight structure, (not chamois type which leaks if not compressed).
Some of the foam types have decomposed a little after 10 years of so, some have become a little harder but the combinations have provided more stable and more silent pads than the traditional ones.
I soon stopped using the small leather washer on the pad (unnecessarily used for getting some flexibility) and have ever since glued the pad directly to a wooden bead on the lever (replacing the mostly used leather piece).
I use contact glue for fixating card, cushion and cover together and PVA glue for fixating the pad to the bead and lever
Card ...often linenpressed 0,4mm...but varies
To adjust the height and leveling the buttons I use paper washers 0,2-0,4mm
There is however often a problem getting these thicker (up to 5mm) pads well fitted in the too small tolerances for lever action and button travel. In order to deal with this I mostly (which I do anyway for comfort) make other buttons with the lever insertion further 'down' on their stem admitting the thicker pads.
Traditional buttons are 'wrong' in other aspects. The guiding pin mostly is too short and they do not admit enough individual variations of height and travel and do not allow use of enough damping on the pins.
When I've had to keep the thickness down I have used the very thin cover and tried to preserve as thick a cushion foam as possible combined with some other material than paper 'card' for the 'card'.
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