Needed (2) Kawai leg bolts

[Ron Overs]

Richard;

Richard Wagner the RPT wrote;

>I have a customer who has a Kawai grand vintage late 1960's. . . . 
>it is missing two of its leg bolts, and I'm trying to track down
>some replacements.
>
>I called Kawai, and they said they no longer stock this type.
>
>They are rather odd in design, with a hole drilled through the head
>(somewhat like a capstan screw but not quite) instead of a regular hex
>head.  However, the head is not of any concern because a regular hex style
>would do just as well. 
>The BIG PROBLEM is that the diameter and thread are un-matchable by any
>means I've tried... And I've tried all I can think of including taking them
>to a bolt wholesaler.  Having them custom machined would be prohibitive.
>Over all length is 3 5/16"  If they are American, they measure out closest
>to 31/64" in diameter.  If metric, they would be nearest to 12.5mm and
>threads appear to be 12/inch.
>
>The problem is they don't match any of the above specs precisely.

That's because the thread they used was 1/2" Whitworth, with a 
nominal size of 1/2" and 13 thread per inch (TPI). UNC 1/2" won't fit 
at all, with 12 TPI it is the only UNC thread between the sizes of 
1/4" and 1" with a different TPI. Whitworth threads are a 55 degree 
form thread while UNC are 60 degree, but they can be used as 
substitutes for each other. This is fortunate, since I find Whitworth 
bolts a pain in the butt. The head sizes require a different set of 
spanners. UNC bolts are much user friendly since the flats are 
standard AF sizes. Getting back to the Kawai bolt issue, I think from 
memory that the diameter of the original bolts is slightly smaller 
than nominal Whitworth but they can still be used, I've done it 
before.

>Before I explore other options such as refitting the piano for standard
>1/2" bolts, or employing a Steinway style cam system perhaps(?) I thought
>I'd check to see if anyone might just happen to have a couple... you
>know... sort of laying around somewhere that they'd be willing to sell?

I do have a couple lying about as it happens but Sydney's a long way 
from the USA. I'd recommend changing all the bolts over with hex 
versions from your local engineers supply. It's a better result 
anyhow, but If you or your client desperately want the originals 
email me using the link below.

Ron O
-- 
Overs Pianos
Sydney Australia
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Web site: http://www.overspianos.com.au
Email:     mailto:ron@overspianos.com.au
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