Just finished this jig for trimming key tops. I have disliked trimming key tops with a flush bearing router bit. We do a limited amount of high end Theran mineral plastic key top jobs. It includes shimming the keys, having the key set and key frame in the shop for really nice spacing, ending up with a really nice looking, well spaced key top job. We've always found the bearing on the flush trim bits frustrating, as it often digs into the key before the bearing stops turning, or never stops turning at all..pisses me off, and ends up widening the key spacing, because bearing digging into the soft pine effectively cuts more off of the key top than we want. I wanted an over-sized bearing by .024. This leaves .012 over sized key top on each side of the key. This way, we could fine tune spacing by hand, rather than have the flush bearing take off more than than we wanted in a first pass...looks quite nice.
We tried a ton of experiments...this one finally worked a treat. Turned an over-sized bearing, which is held concentric to the 5/8" router bit in the table. Since the bearing is not powered, it does not mar the key, and cuts just a tad over-sized for a final tight tolerance, new keyboard-like fit. The left wing on my Unisaw table is set up to be a router table. This jig attaches to the router table.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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