Thursday, February 5, 2015

Brass Flange Repairs

There are times when doing restorative work on period pieces that one encounters an instrument fitted with the continuous brass flange rail for attaching the hammer set at the center pin, rather than the more common wooden single flanges.

The brass flange rail consists of a long strip of brass flat bar that has been cut on one side to produce tongues every inch or so that attach the hammer head, stem, and butt, at the center pin.  These tongues have a small diameter hole drilled into the center of the tongue along with a V groove to accept the center pin. The groove is where the center pin locates to the tongue; a brass clip and steel screw hold the center pin in place allowing the hammer assembly to rotate freely while holding it in its proper position. The entire brass rail itself is attached to the wooden action rail by a series of flat head slot screws.

 There are two major problems I believe are the culprits that cause failure of this set-up. One is that the two metals are not compatible; the steel eventually causes the brass to deteriorate by crystallization of the brass; this, at times, causes the brass clip to fracture, or sometimes the tongue to break away. The second problem is the tremendous vibration and torque at that particular point when the instrument is played. This continuous vibration will weaken the metals as they get older; the brass being the most susceptible to this symptom. 

There are various types of repairs, and repairs clips, for solutions to this procedure. A while back I came across a Canadian built upright that gave me another idea for repairs of this problem. This was a Willis upright, and while it did have the brass flanges and clips for the hammer set, these flanges were not on a continuous rail; each brass flange has its own tongue, clip, and was attached to the wooden action rail as a single flange on its own.  When I discovered this, I thought of how this set-up was much superior to the continuous rail. For example, if a tongue was broken away, the entire flange, clip, and tongue could be replaced without disturbing the rest of the rail, because there is not really a continuous rail there to begin with. 

To install a repair clip that replaces a broken one is relatively easy task to accomplish. The more difficult repair is when the tongue is broken on the rail. So why not take an old brass rail and cut a section out of that for replacement?

Here have a look at these photos; I have some of the usual repairs clips shown and then this idea I came up with for replacement of single brass flanges, or several in a row.

Brass Flange Repairs

UPDATED February 5, 2015

Updated January 2015 I just completed service on the Willis upright with the flanges mentioned in this blog posting. Here are some photos of the brass flange assembly in reversed single flanges instead of a continuous rail. For replacement of the brass clip, both configurations are relatively straight forward. For replacement when the rail tab is broken makes this particular setup of single brass flanges and clips the superior option.

See photo set at link below. 

Willis Brass Flange 

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