Here's the outcome of this project. The spring forming tool (jpg 1) is a jig to also cut the lengths of the arms. The hole at the left end forms the first bend for the loop hook, a pair of needle-nosed pliers forms the second bend. Jpg 2 shows the springs. The new spring has the loop arm 3 mm longer so the loop does not strain at the spring at rest position and the tail 2 mm longer so as not to bind against the wippen but extend slightly beyond. When the loop strains at the spring there is a 7-10 gram difference in tension between rest and full stroke due to the effect of the change in the angle of the loop which changes the draw on the spring. A longer arm causes about a 3 gram difference. A longer arm feels more fluid. Note the change in color after heating the springs in the oven to relieve the strain. Jpg 3 shows the installation. I found THE perfect pin for securing the coil. A plastic tube with a metal rod inserted, it is a hobby store item. The ID of the coil is .090" and the OD of the tube is .065 (perfect fit for the Renner USA cord holes). I prefer a solid support because if you try to adjust the spring tension with a cord support, the cord pulls out slightly. I may have to cove out the front edge of the back check support block if that corner hits the spring but I have that jig too (jpg 11) -- Regards, Jon Page -------------- next part -------------- A non-text attachment was scrubbed... Name: Assist Spring1.jpg Type: application/octet-stream Size: 62378 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20080510/6c90bd62/attachment-0004.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: Assist Spring2.jpg Type: application/octet-stream Size: 82703 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20080510/6c90bd62/attachment-0005.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: Assist Spring3.jpg Type: application/octet-stream Size: 88855 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20080510/6c90bd62/attachment-0006.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: spring cove view11.jpg Type: application/octet-stream Size: 80535 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/20080510/6c90bd62/attachment-0007.obj
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