trimming new keytops

[Dean May]

Great looking jig, Greg. Please send photos of the rest of the jigs.

Dean


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Greg Graham
Sent: Thursday, October 30, 2008 12:53 AM
To: pianotech at ptg.org
Subject: Re: trimming new keytops


My advice, if you are just doing a few sets of keytops, not dozens:

File by hand.  Use a file with a "safe" edge: no teeth on one edge.  Use a
straightedge across the keyboard to line up the notches perfectly. Don't
remove any wood from the sides of the keys.  I built a clamping "vice" with
padding per an old Journal article.  Don't attempt to do lots of filing
without a good, fast-acting key holder of some kind.

If you want to speed things up a little, get a small router, a simple router
table, and build the notching jig Bill Spurlock designed.

For key preparation prior to applying the new tops, I prefer a router
sliding on rails straddling a vice for surfacing the top of the key, and a
sliding table saw jig for trimming the fronts.  Very very high quality
results, very fast, and very safe if you build protection into your jigs.
My 10 year old son is allowed to use the surfacing jig.

I started out building all the jigs Bill Spurlock designed for keytops, but
gradually found better jigs for all but cutting the notch and trimming the
tail to length.  Even they are not perfect, but I have not found something
better.

Two problems I'm hoping to eliminate:

1.  Using the flush trimming router bit with a small, elevated table (to
allow keybutton clearance) I sometimes knock off the corner of the keytop at
the outer edge of the sharp notch by accident.  The guide bearing on a flush
trim bit falls into the undercut at the notch.  I'm thinking about adding an
overhead bar to prevent this, similar to what I see in photos of the old
Oslund machines.  Or, build some type of limiting fence for use with a belt
sander.  For now, I'm just using a file to remove all the overhang.  Slow,
but great results.

2.  The notching jig cuts some keys with the bit cutting "down" into
supported plastic, and others cutting "up", occasionally chipping the keytop
at the notch.  I wish it could cut "down" on all of them.  This problem is
worse if I'm working in a cold shop and the plastic is brittle.

For your information, I don't use the keyfront trimming jig Spurlock
designed.  Used to.  Had a couple keys end up longer because of some sawdust
preventing the key sitting down on the jig, and others that slipped.  I
built a tablesaw jig described by others on this list, and it works better.
Accurate keyfront placement is SUPER important.  The notching jig will index
from the key front.

I also don't use the drill press planer to surface the key.  The router jig
on rails works much better (for me).  See photo.

Back issues of the Journal on CD are a goldmine, but this list is even
better.  You'll find pictures of all sorts of jigs in the archives.

Let me know if you need more info on specific jigs.

Greg Graham, RPT




-- 
Dean

Dean May             cell 812.239.3359
PianoRebuilders.com   812.235.5272
Terre Haute IN  47802
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