Friday, April 27, 2012

Into this neck of the wood.


A little progress on the scroll.  Cut out on the band saw.  Mostl of the initial shaping done with rasp and gouge.  Drilled the string holes.


Roughing out the interior of the pegbox.  This goes fairly quick, but it is a work-out.  I still need to clean up the edges.  Lots of curl in this wood, which means it's very easy to get tear-out where you don't want it - which means I have to resharpen tools before finishing up.  But another day, I need to get back to repair work.


Following, or trying to follow, a scheme by Joseph Grubaugh and Sigrun Seifert for the Brothers Amati Scroll (Strad magazine, March 2006).  I'm not sure that I am interpreting the transition from flat paper to curved surface correctly, but am plunging onward.


A bit of work to cut out the sides of the pegbox and the first turn in the scroll.  This highly figured wood really likes to tear out -- lots of work with the rasp!

Wednesday, April 18, 2012

An adventure in necking.


I had hoped to be much further along, but decided instead to behave like an idiot. I am working on a Brothers Amati model, based on a form I drew following Francois Denis's method. He also has a bit on drawing the scroll, but I am also trying to make progress prior to the So. California workshop in June, so I was trying to save a little time.

I did have a Strad magazine poster of a 1666 Nicolo Amati violin, which has a very similar body to the Bros. Amati outline, so my plan was simple. Scan the scroll part of the poster, print it out, glue it on to a generic neck outline. Close enough for now.

I have a new-to-me computer. The scanner is a few years old. It works fine. I scanned the poster. Print out the scan, and it's huge. Go back to the software, adjust settings, resize the image. After 3 or 4 tries, I have it pretty close to the poster image.

This is a Strad poster from 1996.

I try splicing the scanned scroll onto the neck. Hmmm. It looks a little big. Maybe a lot big. Back to comparing with the poster. Same size. Hmmm. Finally (duh!) I turn the poster over and read the measurements.

Strad magazine has gotten a lot better on their posters over the years. I do remember, however, being cautioned that the photos are not always accurate to size and one should check the measurements against the photo.

That is actually a very good idea.

The poster's scroll was, from heel to end of the scroll, a cm longer than the real thing. Not enough for me to notice out-of-context.

So, back to the drawing-board (computer). A few more re-scaling attempts and I get something that is reasonably close. Attach it to the neck template. Glue it to thin metal. Cut it out, file down the edges.

Not enough time today to mark-out or cut the scroll, but I'm sure ready for tomorrow.

Unless some other conceptual problem pops up.

Tuesday, April 17, 2012

Fiddle hairball


Just another hairball photo. Many players are surprised to learn that a fiddle can have a hairball rolling around inside it, yet it is very common. This one, just above the loose soundpost, is actually fixed in place by rosin that has fallen in through the f-hole.

Some luthiers worry about these hairballs. I know folks who replace them after doing the repair work and others who collect them. I usually just take them out and throw them away, thinking they are something like 'dust bunnies' under the bed. So far, I haven't had any customers who expressed any interest in keeping them, either in their instruments or out.

Saturday, March 24, 2012

Squaring a neck.

I was squaring up a block for the neck this morning before breakfast, just getting a little done while waiting for the rest of the house to get going. This was a rather plain looking block, didn't cost all that much, and didn't seem to nice -- but after removing a little wood, it had quite a nice sheen to it, as well as some nice figure.


Don't know if it will match the back I have for this one, which I think is rather plain, but the ribs are flamed, so a mongrel it will be.

Thursday, March 22, 2012

One small step -- joining a top.



I have been so busy with work lately that I haven't had a breath of time to work on my own instruments. Today, I finally said to heck with it and joined a top. It has been since the end of November when I've done anything towards my Amati Bros. form -- so now I have a top to work with. Small victory, but still a victory.

Saturday, March 17, 2012

1737 Geometrical Construction Error

I have just started reading “Architecture and Geometry in the Age of the Baroque” by George L. Hersey, which was recommended as another good book into the theoretical mind of the time -- connecting music and architecture.

In the book, on pg 16, is Guarino Guarnini’s scheme for drawing a Golden-section rectangle, published in 1737.

There was a clear typo in the text, where

CH:FH :: FH:FA

should have read

CF:FH :: FH:FA


Or at least it seemed obvious to me, then I wasn’t so sure, so I thought, heck, I’ll just do the construction, then measure and calculate the resulting ratios. I tried it 3 or 4 times. Expecting to get 1.618, I was surprised to get 1.73 or 1.74. What the heck is going on? So I did the quick theoretical calculation -- maybe where I should have started -- and found that the ratio from this construction is actually the square root of 3, or about 1.73.

Guarnini’s method is/was wrong. And here it was being presented in an architecture text written in 2000 as being correct. And then, perhaps, in a subsequent edition, there is a footnote (14) that presents the error, though it is not corrected in the text itself.



Saturday, March 3, 2012

Internal edgework and tool marks

A couple fiddles on the bench right now, that I'm trying to fix up, and not 100% sure that it will come out on either, but they had such different internal work that I thought that was interesting. This first one has a very wide platform inside the plate -- so wide that the sanding marks are still easily seen. Before this top was graduated (the inside scooped out) it was, perhaps, held down on a large belt sander to make a flat surface. You can see it here first as a difference in color from the lighter, rougher flat surface to the more defined cut surface towards the f-hole. Note also the stain which has filtered, or slopped, in through the f-hole, and the yet-to-be-repaired wing crack, located by the penciled circle.


Here's another shot of the wide sanded platform left around the edge. A little closer in, you might be able to better make out the parallel sanding marks.


By contrast, this one has almost no platform. The arching dives sharply away from the edge, making a dark shadow. In some places, a previous repairman noted that the ribs overhung too far inside. To 'fix' this, he shoved some woodputty to fill the gap. This back is also darkly stained and has about a pound of dried hide glue, in gobs all over, which I am slowly removing.


Another shot of the very thin edge. If you think of the external overhang, which you can see the stain of on the corner, then go back in 1 mm for the rib, and say, another 1.5-2 mm for the lining, you can see there's not much wiggle room.


The thin-platform fiddle has, on the other hand, a very interesting fake label!


Inside of the "Salomon" violin, as it was when I removed the back (not hard to do, as it was simply hanging on at a few places. The bass-bar appears to be a recent replacement, reasonably done, a new soundpost, and a dust-ball, which is usually a sign that it's been intact and played for a while. Note also the brown staining to the wood, especially visible on the ribs and end-block. Also not the glue spread everywhere on the top, with much excess at the rib-top joint.


Here's the upper-inside back of the "Salomon" violin. You can notice that the wood that was under the neck block and ribs is relatively white, while the rest of it dark. Also note the area from, say, 1 o'clock to 2 o'clock, where I have removed some excess hide glue. The water I used removed some of the 'age'. This is the same water I use to make my coffee, so maybe it will help keep me younger, too! The stain was added to the inside of this fiddle, along with the label, to deceive people. That's it, pure and simple.