Plate drilling/bushings

[Jon Page]

Having fit the block and installed all the screws (a #18 tapered
bit makes it simpler) I center punch the block with a punch I made.
Then I drill the holes on a drill press. When drilling I also align the
holes so the pins attain a position of support along the line of
tension, mostly so the wire doesn't hang up on the pin behind it.

If the webbing holes are close together I ream them with the
same size bit but angle it so as to elongate the hole slightly
towards the rear; otherwise I step up one size (+1/64). I don't
want to remove too much material, a lot of drilling.

I don't use bushings unless they were there in the first place.
I'm not a bushing groupie, yet. :-)
But with bushings, the holes between the bushing and block
need to be aligned. Since I do not drill in the piano where the
holes are aligned automatically, I drill the bushings from underneath
at the pin angle when the plate is out. This keeps the hole centered
at the bottom and angled back at the top.
I you drill a bushing from the center at the top, your hole will be
closer to the plate at the bottom of the bushing.

I just finished a Chickering Quarter grand, two sections with a stepped
flange.  I'm glad that job is behind me.  To mark the blind machine 
screw holes, I cut 1/4" felt punchings and placed them in the holes.
I then placed paint on the end sticking out and pressed the block
down, drilled the marks and got a perfect fit.  It made my day.
In the past I tried different markers but this worked the best.

Jon Page