In one of the PVC-E threads, Dale Erwin asked what is being used for keytop planing. Here I will describe what I built recently for my current project and learning exercise. I was very pleased with the operation and accuracy. I built an overhead router setup based on the concepts presented by Bill Spurlock in the March 1991 issue of the Journal. His fixture of the time was based on a drill press rotary planer. I adapted the concepts to a the overhead router setup. One item that is not clear from the pictures is that a dust collection port is attached to the rear of the fixture. I think that is essential. Notably as built, it does not address Dale's concern about tapered keys. The jig registers on the bottom and side of the key. Photo A shows the overhead router setup with a key ready for planing. Photo B shows the key after exiting the jig. Note that the clamping mechanism is a simple, quick lever which holds adequately and keeps the process moving. The loose plate between the key and lever is coated on the lever side with some beads of hot glue, to provide gripping surface that would not be present in the hard maple. The router bit is a 1-1/2 diameter flat cutting bit. Since the key is less than 1 inch across, this diameter provides a cutting surface for both left side and right side of the key. Order of operation is: 1) With jig against right shoulder insert into about 1/4 inch. move to the left to plane the front edge of of the key (and the existing key front). 2) Slide the sled in to plane the left side of the key. 3) Move the sled to the right, forming the nice edge at the back of the key. 4) Pull the sled out to plane the right side of the key. This order of operation will provide for proper rotation orientation of the cutterhead and produce a splinter free surface. The width between sides of the jig is 300 mm. The sled is 262 mm wide. Other dimensions are determined by the key. Photo C is my working sketch for building the fixture. It is not an “as built” diagram, since I went direct from concept to finished product. In particular the sled and base are longer than indicated in the sketch. They were built to a more “comfortable” length. The base and sled are made of melamine faced particle board for slipperiness. The plated hardware on the front of the slide are rollers sold as sliding door glides at the local Lowes hardware. The purpose is to make the cross cut smooth. Also by using the roller point above the floor of the jig, any chips/debris that the dust collection misses will not interfere with a true reference to complete the straight cut at the back of the key. I found that the simple quick clamp was trouble free and solid for this key set. Another clamp at the rear of the ivoried section would provide additional security. I was going for for the min-max of hardware/accuracy. For this key set it met all of my expectations. I expect it will evolve some with different key sets in the future. Photo D is the result. Full resolution photos are available here: http://www.flickr.com/photos/duanemcguire/sets/72157622759095507/ -- Duane McGuire 801-830-5858 http://blog.duanemcguire.com -------------- next part -------------- A non-text attachment was scrubbed... Name: Photo_A_before.jpg Type: image/jpeg Size: 115903 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100101/e38da97f/attachment-0004.jpg> -------------- next part -------------- A non-text attachment was scrubbed... Name: Photo_B_After.jpg Type: image/jpeg Size: 102553 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100101/e38da97f/attachment-0005.jpg> -------------- next part -------------- A non-text attachment was scrubbed... Name: Photo_C_sketch.jpg Type: image/jpeg Size: 113630 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100101/e38da97f/attachment-0006.jpg> -------------- next part -------------- A non-text attachment was scrubbed... Name: Photo_D_result.jpg Type: image/jpeg Size: 106621 bytes Desc: not available URL: <http://ptg.org/pipermail/pianotech.php/attachments/20100101/e38da97f/attachment-0007.jpg>
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