Brasswork for the harp

Things are coming to a head! If nothing untoward happens this baby will be ready for strings next week.

I added some cherry reinforcing inlay to cover the topside glue line. The loop in the corner is just for fun.

Several attempts to apply an etching mask to the center strip failed. I had a really cool design worked out but here is plan B, done with various cutters in the drill press.

And here it is setting on the harp. The curved bit at the top is where the strings fan out from under the neck.

Here are the cheek bands. The holes are too close together for the same treatment as the center strip so they are just chamfered a bit. 3/4 of the nails (brass escutchion pins) are decorative. The onnes in the photo have been cut off and peened flat on the back side.

I researched the diameter of 18 ga pins and found .0403 DIA so I got a #60 and a #59 drill bit. Afterwards I had to find the pins at a different store. hey are .010 oversize, so today I invested in a couple of #55 bits. The first one broke off in the first hole I tried to drill.  The second one broke four holes short of finishing the first cheekband.
What to do?  I actually managed to sharpen the bit (.052) not just once but twice after I broke it a second time. So three broken bits, two sharpenings and I got all seventeen dozen tiny holes drilled and the decorative pins hammered in.

Here is a close up of the cheek bands. The wee empty hole are for the nails that will fasten the brass to the harp, the tuning pins will run through the larger holes.

Major wood work complete!

 The three big parts are pretty much done. Fitting the neck/pillar to the box is always a challenge.  On my usual designs I fasten with nuts and bolts in hidden places. For this harp I have used the mortise and tenon design from the Queen Mary harp. The tenons and mortises are parallel front and back and the top of the sound box is cut to be perpendicular to the strings. This reduces the stress on the tenon.

This would be tricky enough as it is but the pillar is also tilted so that the top of the string is centered ( whuch means the top of the pillar is off center about an inch. This leads to a situation where small adjustments at one end are magnified at the other. Plus the mortise at the bottom of the pillar is a blind fit and needs to be accurate to take the pressure of the strings at tension.
There was lots of putting together, taking apart, trying to asses where things are binding, shaving here and there, rinse and repeat.

 Here is the final result. It's a very tight fit at both ends. Of course  this will all change when the strings have been on for a few weeks!














The transition between the top of the sound box and the neck looks abrupt and unlovely as it is.
However after some more quality time with the rasps and sandpaper blocks....

Time to change gears and start the brass works.

Getting there!

All the major pieces for the box are cut and fitted.

Here is the box from the outside

That's a pretty piece of walnut!

Here's the view from the inside.

And this shows the disassemble parts. You can see some of the joinery.

Finally the outside view of the parts.

The are scraped and cleaned, ready for final inspection and if all the looks OK then its on to dying, grain filling and a wash coat of shellac to protect from glue stains - then we'll put this puppy together!

Marching on...

I have been cogitating on a way to minimize the risk of splitting the soundboard on this harp. It is so wide (about 20") that I'm concerned that running the base with the grain 90° to the soundboard will not move with the seasons.
A carved box would have the grain in line but has little strength.
In addition the lower edge of the soundboard is in tension - not a good situation for the glue line.

The solution I have elected is a blind dovetail joint.

It's a little challenging to make this joint but if I can pull it off it will be elegant.

Here the right half of the bottom is lying on the right side of the soundboard (I 'm not dyslexic - we're looking at the inside of the harp in these images.

The tricky thing about this joint is that you can't see anything when it's together, and it's difficult to see anything whilst cutting it.

Not too bad. This is the view from the inside. Note that the grain is running in line with the soundboard. The dovetail joint should keep the soundboard from lifting off the base.

Here's the view from the outside.

I'm doing the base in halves because there is a foot extension that comes through the middle - basically a 2x4 - which will have the mortise for the foot of the pillar and also provide support to help hold the harp in playing position.