Got the go ahead to replace the backrail cloth on a K. Kawaii KG-1C grand ser. no. 752272 (1974?). It is a bit of a drive away in the wrong direction. Does anybody know what width and thickness I should order? Mark Wisner from Kawaii said to use "medium", but Pianotek says they don't know what size that would be... I can easily determine the correct thickness by checking the dip and blow with samples (after a long drive), but I would still not know the correct width. You see, what is there now is deteriorated foam rubber, not original for sure. There is no telling what the history is. There doesn't seem to be much wear. It was donated by a dealer from somewhere...

For the small expense, compared to driving there.

I would plan to arrive with one of each of the available sizes.

Pianotek lists 19 sizes, Schaff only 7. Would 1-1/2 inches wide be correct?

1-1/2 looks about right, looking at my old service manual.

Why are you replacing the backrail cloth?

Thanks, BDB.

Dale, On a tuning visit I noticed that some of the keys were higher than others. After pulling the action I found that the backrail felt was deteriorated so bad that it affected the key height in some areas. It turned to powder just from touching it. I don't think it is felt, but spounge rubber. I'll make sure that I have felt punchings just in case. The hammers and dampers seemed fine, though.

You can always go with some thinner material and then shim it up with bushing cloth.

This is a really old kawai if it has the neoprene foam type material. Take along several type of felt and thinner cloth. Medium back rail may be too thick. Like Ryan said, you can always use layers to get the right height.

The procedure would be to set the height of the front of the key using the front rail pin and the key slip as the parameters. Some times the capstan is a factor.Then adjust the back rail cloth to achieve that result. If you want thicker back rail cloth, you need to raise the key at the balance rail. Take some sets of balance rail punchings too. Put together a kit of the paper punchings, they are cheap. Maybe some pear green or wurzen front rail punchings.

Now you can make the key travel the proper distance for this or any action. This is the first step of action regulation and probably the most important. Key dip!!!! Set it.

Only glue the front edge of the back rail cloth. The landing of the back of the key is softer. Cardboard is acceptable as a shim as well as thin felt. I like cereal boxes.

Thanks All:

This is a "Git-er-Dun" project. The customer(s) never noticed the 1/8 inch difference in key height of the affected notes to begin with. I ordered a small collection of different thicknesses and have an assortment of punchings and shim material. It is somehow reassuring to know that this is factory installed foam rubber. Otherwise, why would it be there?

Even if it was factory installed, I do not understand why it was there!

“Gut-er-Dun”

It was felt after all, insect damaged. The light green, granular bug droppings reminded me of deteriorated foam rubber.