We do a small quantity of high end key set restorations and theran/ivopoast installations. After messing with flush trimming bits for years, we finally made this rig which eliminates the spinning bearing which always marrs the keys. Also it allows us to install a slightly oversized bearing. The oversized, non-spinning bearing, allows us to final size and space the keys, by hand, with a high degree of accuracy and with minimal key-to-key clearances.
I tried all the Spurlock ideas, but they just resulted in the kind of key top work that really does not result in a new really even and clean installation.
...I feel the OP's pain on this.
Also keep in mind, re the OP's experience, the sides of the key are not necessarily square to the trimmed top surface. This is either caused by the top trimming process, which done sidewise on a table saw, is fraught with angular inaccuracy, or the keys have shrunk over the years into a trapezoidal shape. If the key sides are not perpendicular to the top surface, the bearing will ride on the non-square side and remove more stock than you want to remove. This is why, as a high end key service, we only work with the keyframe in the shop, and shim and space the keys as needed before any key tops go on.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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Original Message:
Sent: 07-12-2021 03:13
From: Michael Kurta
Subject: Trimming new plastic keytops
Bill: Here's my recipe for trimming keytops. Using a router table with a flush trimming bit coming up through a hole in the table, push the key lightly against the cutter and slowly move it through its length. Two things: Be aware of the bit rotation and always move the key against it. And be careful of lead weights as the holes in the key as the lead can cause you to cut deeper than you want as you pass by them. Oh yes, add a layer of felt around the hole in your table so as not to mar the plastic as you move it by the cutter.
Mike Kurta, RPT
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Mike Kurta, RPT
N. Michigan chapter
Original Message:
Sent: 07-11-2021 18:45
From: William Ryder
Subject: Trimming new plastic keytops
Hello Fellow Technicians,
I've just glued on some new plastic keytops and am trying to figure out the best way to trim off the excess plastic on the sides with a router and router table. I have a top bearing flush trim bit and a bottom bearing flush trim bit.
I used, with some practice keys, the top bearing bit (actually bottom bearing when the router is upside down in the table). With the bottom of the key stick flat on the router table top and the bearing of the bit against the side of the key stick I moved the key through. However, the bit took away some of the wood with the plastic. Perhaps I pressed too hard against the bit.
I'm planning on using the bottom bearing bit (actually top bearing when in the router table) for the other side of the key and running the key through with the keytop down on the table.
If this rings any bells with anyone and you have any tips for me please let me know. Maybe there is a easier way to do this.
Thank you in advance for your help.
Bill Ryder RPT