Square pianos are largely wood and wire construction, but there is a need for some bespoke hardware that can be a devil to find as modern replacements. In general, if you want to keep an authentic look and feel there will be lots of bits you may need to make yourself. On this page we will start to cover some of this activity, so check back in from time to time to see what we have added!
We’ll start with the subject of hinges. These are invariably cast brass as opposed to the rolled modern versions you are likely to find, and the look of course is different. Sizes were not exactly standardized either, so modern hinges may need new mortises cut and holes drilled, and it’s a pity to take the chisel and drill to our antiques simply because we want to install the wrong hinge!
We begin with a case of the reproduction hinge leaf, for an early square now under restoration by David Hackett. In this instance, aesthetic needs around a lid that has shrunk over the last 240 years requires that the hinge flap be extended to allow the lid to lap over the front of the instrument. Cutting deeper mortises would be possible but goes against the code of minimizing impact of the restoration process. David explains it as follows:
“As you know, it’s a common problem for the mahogany to shrink across the grain, so the front overhang is lost, and the lockboard doesn’t fit properly. Moving the hinges on the lid looks terrible. Recessing them into the spine is easy, but involves loss of wood. So I made new hinge leaves, a bit longer.”
David starts by choosing a brass plate the correct thickness, and a brass rod close to the diameter of the hinge. This rod can then be chucked in a drill press or lathe and turned down to the correct diameter. In the drill press, a piece of 1/8″ steel drilled to the correct diameter can be used to easily press the brass through and obtain the correct final diameter.
From David we understand: “Picture 1 shows the oversize rod turned down to correct diameter. This works in an ordinary chuck on a wood-lathe or drill. The reason for making the two pieces end-to-end is simply that it’s a bit more stable. Holding little bits in place is not easy. Fingers not a good idea, wood not much better, and metal tends to become part of the job! There is one safety point I would like to mention for the benefit of beginners – they MUST use fire-bricks to assemble the ‘hearth’. House-bricks and concrete can explode with very unpleasant results.”
This last point is quite true. Some low temp regular brick and all concrete has what are called ‘waters of hydration’ which is water trapped chemically in the ceramic matrix, as well as pockets that trap water in the ordinary way. Under intense heating this water can release suddenly as steam resulting in large flakes of material coming at you at high speed!
Here is the rod lined up with the plate for brazing.
Immediately after the brazing step, ready to clean up.
Same plan, two in one to be cut apart later.
The rod notched to receive the old mate. It helps if the old mate has the outside journal to use as a boring guide as you see next.
Boring the hinge pin hole in the new material.
Ready to install, the new one compared to the original.
I am currently bringing up a Longman and Broderip, where the lid was allowed to be twisted off, resulting in two of three hinges broken and mangled. Replacements always look like new, so what to do? Using the brazing technique, we can bring these back to useful condition.
Start by punching the hinge pin out to separate the leaves, then heat the broken leaf pieces to anneal them. Clamp the edges to bring them back to flat. Yes, there are stress cracks in the brass but we will take care of that shortly.
Next, file the rough edges so that the hinge comes back together. Ignore the voids for right now. Put the pieces on your firebrick, and wedge them together with a second brick to secure them together. Then just heat up the crack line and fill in with brass from the brazing rod as above. It is OK if the mounting holes should partially fill, we can drill those back out later.
File the resulting hinge-fill flat, wire brush, and optionally use the buffing wheel. One hour later we have three fully functional hinges with substantial authenticity, and they are ready for another 200 years, which we hope will be kinder than the last 200!
This piano was also missing all of the damper control levers on the left side. This is also a relatively easy reconstruction task. Original wrought iron was 3/16-1/4 in. thick material. We can easily get these thicknesses of hot or cold rolled steel for welding and masonry support at the local hardware store for a few dollars, in widths of 0.5, 1.0, and 1.5 inches. We start with the cranked lever, often used for the bass dampers. It is an easy shape to transfer to a wider steel bar. They were usually 1 to 1.25 inches wide or so, and the 3/16 ” matches authentic material closely for this year. Early pianos often used wrought iron closer to 1/4 “, but variation abounds.
Here we see a freshly cut lever and the original bar stock. The tiny bit at the far left will be threaded to fit a cast reproduction knob as supplied by our friend David Law at Traditional Brass. See our links page. We leave the lever overly long for final fitting on the piano. The dimensions here were 17″X 0.4 inch, with the screw end 1/4 X the 3/16″ thickness. This will thread well enough to fit our knobs, but David can supply you with whatever thread you choose.
Cutting the steel will present a challenge. With a fresh hack saw blade, this cut takes about 40 minutes of rather a lot of sawing. However, it is straightforward and sure if you will clamp up your piece properly as you cut.
Quicker approaches might include fitting an abrasive cutoff blade on your table saw. Indeed, the cut down most of the long length is well under 5 minutes with a 10 inch blade. Two cautions! First, completely remove all sawdust from your saw before cutting iron. Residual can (and will) begin to smolder and burn. A leaf blower is useful for blowing out the saw first. Second, your bar stock will heat rapidly and expand as you cut. Unless you quench, this will drive the abrasive blade away from the fence and the cut will start to wander. So cut about 3/4 inch, withdraw and quench in a bucket of water, then cut again. This goes fast once you get the rhythm. Don’t cheat and keep cutting, for once you wander you are lost. Leave the blade at maximum height to minimize the angle of the cut.
A band saw is great if you have a powerful one that you can fit with a wide blade intended for cutting steel. Slow blade speeds and steady pressure is the ticket here. A dribble of oil as you go works wonders as well. 3/16″ is about the max for most hobby grade saws, and the cut may be as slow as by hand, but a professional Rikon or similar can cut much thicker material.
The Case of the Missing Wrest Pins.
Not uncommonly, a string will break and the well meaning owner or technician draws the wrest pin, meaning to restring a replacement, and it never happens, so pins go missing. Thankfully, these are rather easy to replace with common nails or rod stock. Early wrest pins are usually between 4 and 5 mm in diameter. A 16 penny common bright nail is about 4.2 mm diameter, a 20 P nail about 4.9 mm. Broadwood pins are generally ~5 mm for 18th C models, and other builders including Longman and Broderip used a variety of diameters between 4 & 5mm. In the UK, 18 P nails are still available but not in the US. So when we have a specialty diameter in the US, we might need to turn down the diameter of a 20 P nail to fit but not too snugly. Usually, one of the common nails will work fine.
Old wrought iron was soft enough to flatten while hammering cold, but a modern nail will need to be heated and annealed to allow that, and so once we have it hot why not just hammer then, and save time? We start by selecting the correct diameter bright finish nail, and, retaining the chiseled end, cut off the head and shoulder to the correct length (~50 mm for most pins), measuring from the point where the chisel starts to taper, to allow room at each end to dress the final length. A bolt cutter is quick for this, but leaves a cut end that needs dressing, so a hack saw, band saw, or abrasive cut-off blade can actually be shorter in the long run. The early suppliers probably cut these with a chisel from hot rod stock, so you can try that also.
The next step is to chuck the cut nail piece in the drill press, tighten the chuck, and with a medium cross cutting bastard file apply it to the last 15 mm or so of the pin at a shallow angle to create the taper.
This should obliterate all signs of the chisel marks leaving a pin with a rough taper to a rounded point. This slight taper allows you to hammer the pin in the original hole and hopefully by controlling the depth, you can adjust the tightness. The hole should taper ~1 mm or so to the end but no more, until you hit the very end of your point.
As a final dressing, set the file on edge and turn a spiral cut into the nail to grip the wood, or give it a few licks to roughen it by rolling a coarse file over the pin while on your table saw table.