Square beam construction

[pmb]

Dear all,

In older (e.g. Victorian) organs, squares were frequently attached to their supporting beam in a manner which enabled them to be removed individually.

In modern instruments, typically the squares are carried on a common wire or rod which acts as the pivot for all the squares. The wire passes through the beam along its entire length. Slots are cut in the beam for the squares to work in. The wire passes through a hole in the square. Presumably, this is an easier way to construct the action as there are less individual parts to make.

Since I first saw this arrangement in a German organ many years ago, I have wondered how such a beam is drilled. Perhaps the beam is made in two parts and a groove is made in one part before the two are glued together? 

I would be grateful if anyone could enlighten me!

[pwhodges]

My grand piano has its hammers pivoted on a long rigid wire they're threaded on to.  It's the only piano action like it I've ever seen (Broadwood "Red Beam" action - made from about 1895 to 1905).  In this case the wire is held in place by metal clamps between the hammers, so no long drilling is required.

Paul

[pmb]

Thank you Paul. You reminded me that Victorian organs often have their squares (or backfalls, for that matter) carried on a long wire which is held against the beam by staples, the wire being located in a groove along the length of the beam. Perhaps this was developed further into the construction I queried above?

[Colin Pykett]

If I understand your query correctly, it's a similar problem to that met by those who want to make tall standard lamps in which the power cable runs through a long hole.  There are several techniques for this - just do a web search.  One is indeed the method you suggested in which the beam is made from two parts in which the groove/hole is first routed before they are glued together.  In the case of the lamp standard it is then turned up to be cylindrical or whatever curvy shape is desired, but often it is made up of several shorter lengths.  It's not something I've tried, either for organs or lamps, and (not surprisingly) there appear to be various pitfalls to avoid ...

[pmb]

Thank you Colin. I see the similarity with the standard lamp but also some important differences: the boring is typically much wider and a wider bit may be less inclined to wander off course; the external turning can be done between centres when the boring is completed which would negate any error in the boring. In fact, it's rather how I imagine wooden pipe feet might be made (bore the square stock first, then turn the outside). Perhaps someone knows how this is usually done.

But regarding construction of the square beam, I'm still puzzled.