Hitch Pin Plate Drilling

[David Love]

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Never mind.  Didn't read carefully enough.   I see that your drilled the
same size as the pin.  Does that work out?  When I've tried to drill out
for new pins it seems that the hole ends up slightly bigger than the
drill size and the pin is often slightly loose.  How should it be?
Should one be tapping them into a snug fit or do you worry about
stressing the cast iron if they are too tight.  Should they be secured
with epoxy?  What's the approach?
David Love
davidlovepianos@comcast.net 
-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Michael Spalding
Sent: Thursday, June 23, 2005 12:16 PM
To: Pianotech
Subject: RE: Hitch Pin Plate Drilling
 
Terry,
 
Recently faced the same problem on my first and only vertical hitch pin
conversion.  Bass bichord hitch pins alternated fore and aft, but still
not enough space to make me feel comfortable picking a new location.
Old pins were reasonable tight, so I left them in place, ground them
flush with the top of the plate, and drilled the new holes down through
the center of the originals.  3/16 diameter (larger than the originals
at .156) and 9/16 deep (considerably deeper than originals).  Thus the
top and the bottom of the new hole are in fresh cast iron.    Needed the
drill press because the original pins were harder than surrounding cast
iron - couldn't push the drill in by hand.   See photo.  New pins will
be 3/16 x 1", with 7/16" exposed.  If I set the height of the new bass
bridge cap correctly, the loops will rest about 1/8 above the plate.  
 
Mike
 
 
----- Original Message ----- 
From: Farrell <mailto:mfarrel2@tampabay.rr.com>  
To: pianotech@ptg.org
Sent: 6/21/2005 2:39:41 PM 
Subject: Hitch Pin Plate Drilling
 
I'm about to drill a plate for vertical hitch pins. On the few plate
I've done this to, I've always had enough fore-and-aft room in the hitch
pin area to place the new hitch pin at a desirable location, and not be
real close to the original hitch pin. Unfortunately, on the plate I need
to drill, the hitch pin area is relatively narrow and I can't go very
far fore or aft with the new location. I can only assume that the
original steel pin is a lot harder than the cast iron and I must avoid
hitting it. Agree? Any general advice on placing the new hitch pins in a
situation like this from those who have crossed this bridge (or rather
hitch pin area) before?
 
I could go immediately aft of the originals, but that would put all pins
in one line - although the originals held up for 100 years in that
array. Should I just do that and not worry about it?
 
Terry Farrell

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