key trimming bit

[Dean May]

For those who are curious here are some pictures of my notch cutting set up.
The way the jig is set up the router is mounted underneath the table. The
key is passed over so that the bottom of the bit trims the long side of the
notch and the side of the bit trims the short side of the notch. I used an
"upcut" bit because the router is upside down (so it is really "downcut"
now) to pull chips away from the work to below the table.

 

Because of the way the key edge passes longitudinally past the bit it
doesn't seem like upcut or downcut would make any difference. We get
breakout no matter which direction we approach the bit.

 

I am using about a $200 Bosch router so it should be good, but I'll check
the wobble with a dial indicator.

 

Sounds like warming them first is the solution. This list is fantastic.
Thank you all for sharing so generously.

 

Dean

Dean May             cell 812.239.3359 

PianoRebuilders.com   812.235.5272 

Terre Haute IN  47802

 

  _____  

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Farrell
Sent: Friday, March 14, 2008 11:31 AM
To: Pianotech List
Subject: Re: key trimming bit

 

Dean, I don't know a darn thing about trimming keytops, but I have used
spiral router bits a fair bit. If the router is above the keytop, shouldn't
you be using a down-cutting spiral bit to minimize breakout? A downcutting
bit should leave a smooth cut on the top (router side) surface at the
potential sacrifice of the lower surface (although if there is wood bonded
to the underside of the keytop, I should think that there will be no
breakout on the underside of the keytop).

 

Terry Farrell

----- Original Message ----- 

 

I am using a Spurlock style set up to trim my keytops and am having trouble
with the plastic chipping out on the notch cutting station. I am using a 1/2
inch spiral carbide up cut bit from McMaster Carr (27395A31). Is there a
better router bit I can be using here? 

 

Dean May 

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