Hi all,
In Part 7 we installed the Belly Rails, Lower Braces, and some case moldings and runners. Now we will install the Upper Braces, pinblock support bracket, and construct and temporarily install the pinblock. This will conclude the construction of the case. Let’s get started!
The Upper Braces are all glued to the bentside and serve to dissipate the pulling force of the strings on this case member. They are made out of 2 pieces of ¾” poplar stock that are face glued to form a 1 ½” thick brace. The first photo shows the 5 Upper Braces which have already been fit properly in the case.
The next photo shows the first brace being glued into the case. At the front end it is clamped with screws going through the Belly Rail. On the bentside end it is clamped with screws from the outside of the case. It is also glued to the underside of the bentside soundboard liner and is clamped to it while the glue sets.
The next photo shows the first two braces being installed.
The remaining Upper Braces are similarly glued in. The next photo shows all of the braces that have been installed.
Although the case is now amazingly strong there are two more things we can do to make it even stronger. First, we install an Upper Belly Rail stiffener. This strip of wood is ¾” thick and 1 ½” wide and stiffens up the Upper Belly rail. It is glued to the Upper Belly Rail and to the top surface of the 2 Upper Braces that contact it.
Secondly, we install small braces on the bentside end of the Upper Braces. These small braces bear against the bentside liner and further help it to resist pulling forward under the tension of the strings. We’ll just tack them in place with a few brads while the glue sets. The next photo shows these small braces.
All that remains to do now is to install the pinblock. The pinblock is a thick slab ( 1 ½” ) of red oak that the tuning pins will be driven into when we string the instrument. In order to install it at the correct height (its top surface must also be level with the top of the Upper Belly Rail) we will make and install 2 pinblock support brackets. The following photo shows these 2 brackets which are also made of red oak.
These brackets will be glued and screwed into the spine and cheek sides. The pinblock will be glued and screwed into these brackets. The next photo shows this installation.
Next we’ll take two pieces of ¾” thick red oak and face glue them together to make our pinblock. The plank is oversized in length and width at this point. A couple of brads are shot into each end to keep the two pieces more or less aligned while the clamps are applied. After the glue sets, the blank is jointed and cut to its proper width and length.
The next photo shows the pinblock in its position in the case. Notice the gap between the pinblock and the Upper Belly Rail. For some reason unknown to me, this gap is called the “Gap” (clever folks these harpsichord people are). Directly below the gap will lie the rear end of the keyboard and the jacks will come up through the gap to pluck the strings.
The pinblock is screwed into the pinblock brackets at both ends. These screws will not be removed. They are the only screws in a harpsichord that have a function other than clamping. The strings create such a strong pull on the tuning pins that it’s possible for a pinblock to be lifted up off of the pinblock brackets thereby making tuning impossible.
At this point no glue has been used because the pinblock will have to be removed to drill the holes for the tuning pins. The screws have been recessed because the entire pinblock will be covered with 1/8” thick spruce to match the soundboard. Eventually the pinblock brackets and pinblock will be re-installed with glue.
All that remains to do is to remove the 43 screws (yea, I counted them) we used for clamping and plug them with poplar plugs. Wood putty or Bondo will eventually show through the finish so I prefer plugs whenever possible.
That’s about it for the case. The next photo shows the harpsichord on its spine to show the entire inside.
And finally, the instrument as it is now.
I need a change of pace so I think we’ll tackle the registers next. Get your scrollsaw ready.
See you then,
Ernie
Part 1 - The Keyboard Part 2 -Keyboard con't. Part 3 - Keyboard con't. Part 4 - The Case (Bentside) Part 5 - Case Bottom Part 6 - Case Sides Part 7 - The Lower Braces Part 8 - Case Finished Part 9 - Building the Registers Part 10 - The Stand Part 11 - Jackrail & Moldings
Part 12 - The Music Desk Part 13 - Building the Benchhttp://www.ncwoodworker.net/forums/f101/harpsichord-project-part-12-music-desk-18962/
In Part 7 we installed the Belly Rails, Lower Braces, and some case moldings and runners. Now we will install the Upper Braces, pinblock support bracket, and construct and temporarily install the pinblock. This will conclude the construction of the case. Let’s get started!
The Upper Braces are all glued to the bentside and serve to dissipate the pulling force of the strings on this case member. They are made out of 2 pieces of ¾” poplar stock that are face glued to form a 1 ½” thick brace. The first photo shows the 5 Upper Braces which have already been fit properly in the case.
The next photo shows the first brace being glued into the case. At the front end it is clamped with screws going through the Belly Rail. On the bentside end it is clamped with screws from the outside of the case. It is also glued to the underside of the bentside soundboard liner and is clamped to it while the glue sets.
The next photo shows the first two braces being installed.
The remaining Upper Braces are similarly glued in. The next photo shows all of the braces that have been installed.
Although the case is now amazingly strong there are two more things we can do to make it even stronger. First, we install an Upper Belly Rail stiffener. This strip of wood is ¾” thick and 1 ½” wide and stiffens up the Upper Belly rail. It is glued to the Upper Belly Rail and to the top surface of the 2 Upper Braces that contact it.
Secondly, we install small braces on the bentside end of the Upper Braces. These small braces bear against the bentside liner and further help it to resist pulling forward under the tension of the strings. We’ll just tack them in place with a few brads while the glue sets. The next photo shows these small braces.
All that remains to do now is to install the pinblock. The pinblock is a thick slab ( 1 ½” ) of red oak that the tuning pins will be driven into when we string the instrument. In order to install it at the correct height (its top surface must also be level with the top of the Upper Belly Rail) we will make and install 2 pinblock support brackets. The following photo shows these 2 brackets which are also made of red oak.
These brackets will be glued and screwed into the spine and cheek sides. The pinblock will be glued and screwed into these brackets. The next photo shows this installation.
Next we’ll take two pieces of ¾” thick red oak and face glue them together to make our pinblock. The plank is oversized in length and width at this point. A couple of brads are shot into each end to keep the two pieces more or less aligned while the clamps are applied. After the glue sets, the blank is jointed and cut to its proper width and length.
The next photo shows the pinblock in its position in the case. Notice the gap between the pinblock and the Upper Belly Rail. For some reason unknown to me, this gap is called the “Gap” (clever folks these harpsichord people are). Directly below the gap will lie the rear end of the keyboard and the jacks will come up through the gap to pluck the strings.
The pinblock is screwed into the pinblock brackets at both ends. These screws will not be removed. They are the only screws in a harpsichord that have a function other than clamping. The strings create such a strong pull on the tuning pins that it’s possible for a pinblock to be lifted up off of the pinblock brackets thereby making tuning impossible.
At this point no glue has been used because the pinblock will have to be removed to drill the holes for the tuning pins. The screws have been recessed because the entire pinblock will be covered with 1/8” thick spruce to match the soundboard. Eventually the pinblock brackets and pinblock will be re-installed with glue.
All that remains to do is to remove the 43 screws (yea, I counted them) we used for clamping and plug them with poplar plugs. Wood putty or Bondo will eventually show through the finish so I prefer plugs whenever possible.
That’s about it for the case. The next photo shows the harpsichord on its spine to show the entire inside.
And finally, the instrument as it is now.
I need a change of pace so I think we’ll tackle the registers next. Get your scrollsaw ready.
See you then,
Ernie
Part 1 - The Keyboard Part 2 -Keyboard con't. Part 3 - Keyboard con't. Part 4 - The Case (Bentside) Part 5 - Case Bottom Part 6 - Case Sides Part 7 - The Lower Braces Part 8 - Case Finished Part 9 - Building the Registers Part 10 - The Stand Part 11 - Jackrail & Moldings
Part 12 - The Music Desk Part 13 - Building the Benchhttp://www.ncwoodworker.net/forums/f101/harpsichord-project-part-12-music-desk-18962/
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