Saturday, November 28, 2009

Student instruments

Student instruments are always problematic. They can suffer a great deal of abuse, unintentional and otherwise. Makers of student instruments -- factories almost always -- in the best of situations have to make something quick, strong, and reasonable. In other cases, they produce outright junk, which can neither be played nor repaired. If you are buying a new violin for $100, for example, you are buying junk.

Parents want their kids to succeed, and they want to save money. When it comes to material goods, however, the parents often think of the cost alone. A child learning to play a musical instrument can be handicapped by an unplayable instrument. That is no value, just cost, even if it is minimal. Learning, however, is the important thing -- that is the value. Any thought of resale value, particularly in a student instrument, pales in comparison to how the child's brain can be developed.

Here is a fractional cello that came into the shop recently. The top had cracked near the tailpiece. I could recognize it as the result of the endblock shrinking -- a very common event on low-end instruments. Preventable with good quality control, but right now that is not important to these makers. They sell instruments easily, so why change?

This one retails for about $1200, not a small amount of money for most parents in this area. And it is not the 'bottom of the barrel' -- I can actually get the top off in a reasonable amount of time with a minimum of damage.

For comparison, though, I thought it might be interesting to show some of the inside details, that don't show up when looking at the shiny new instrument.

Here's the lower corner block on the bass side --


Notice how the block has been roughly split out, and that the c-bout linings, rather than running inside the block, actually stop far short of it. If the glue fails here, these will spring loose, creating quite a buzz.

To show that it's not a fluke, here's the lower treble-side corner block.


It has similar problems. Again, to be fair, these are made very quickly. Any extra time is spent on the outside, the part seen by the customer.

The endblock was just as rough. In this photo, you can see one split-out side, where the drill had been quickly pushed through, probably after the top was glued on. It had a similar fragment, hanging by a thin fiber, on the other side, which I had removed prior to this photo.


Note that the block is loose from the ribs. It is harder to see that the ribs themselves are split, radiating out from the end-pin hole. You can see a linen cleat that I have installed on one of the cracks. This type of damage happens when the cello is dropped on its endpin. A better block, however, might have held.

Thursday, November 26, 2009

A bass-bar and family history

A follow-up on the November 10 post -- out with the old, and in with the new.


I glued the top on a couple days ago, and will install a spiral bushing in the A-peghole, which had been split and repaired sometime in the past, though not well.

Monday, November 16, 2009

Attaching the fingerboard

Before the final shaping of the neck, the fingerboard needs to be shaped and installed. The ebony blanks come basically fingerboard-shaped, but far too bulky. With a series of planes, gouges, and scrapers, I reduce some of the mass from underneath as well as from above.


Once the fingerboard is in reasonable shape, I layout its position on the neck and then glue a few locater studs, in this case 2 on each side. This makes it easier to put the fingerboard on in the right place when the slippery hide glue is on.


I glue it on firmly, not a simple tack, because it's going to stay on. I use the fingerboard to help align the neck while fitting, and leave it on while varnishing, as was done in the old days.

Sunday, November 15, 2009

Medieval Fiddle, part 1

It's something I've wanted to build for some time, but haven't yet. We now have a group of Renaissance enthusiasts who are putting together a Ren Faire next year. They contacted me looking for musicians, dancers, etc., so I thought this would be a good excuse to actually get to work on one.

Here's a Medieval fiddle in action.

I had a plan for one, so got it out, laid over some tracing paper, and marked it out with pencil.


There are bound to be other, better ways to do this, but this is how I approach making a violin mould, and it's what I know. Once the tracing is adequate, I need to make a stiff template in that shape. In the past, I have used thin metal, because it's durable, but for this one I'm going to try something easier to cut, and use what's on hand. I had pickguard material, such as used on guitars, lying about, so glued the tracing onto it.


With a knife and file, I cut it out, and smoothed it up. I have left a tab to the far side, with a couple holes along the center line. These are used to put the template down in the same place -- a registration device.

Again staying with the simple approach, I found a piece of construction grade plywood in the shop, left-over from a bit of roof replacement we did a couple years ago. I lay-out a centerline, then drill a couple holes corresponding to the holes in the template, and drive a modified 16d nail into each hole. The modification is that I cut off the heads and rounded the shafts. I use a small machinist square to make the nails square to the plywood.


Next, lay the template on the nails, trace out one half, pull the template up, flip it over, trace the other half. Remove the template and cut it out. Actually, I cut close to the line, then finish up with files, knives, planes -- whatever works for any particular part. One problem with construction grade plywood is that it's a bit coarse in plys, so is easy to tear. On my violin moulds, I use a higher grade birch plywood with more, and thinner, plys.


At the inside corner of each block I drill a hole to allow for glue squeeze-out. The big cut-out in the center is simply for clamping. I use modern clamps to hold the blocks and ribs in place while gluing. A traditional method, at least for violins, would use round holes for dowels. String is then used to hold the ribs or blocks in place while gluing.

Tuesday, November 10, 2009

Humble repairs

I've been busy with repairs the past couple days, which is good for immediate cash flow, but takes time away from making. Today, for example, I took the tops off two cellos and one violin, not one of them really worth working on. The two cellos are modern Chinese-made instruments, but even so retail around $1200. Since these belong to end-users, who pay retail, they decided to get the repairs done. Both are being used by school orchestras, and tend to take a fair amount of abuse.

This one was badly damaged.


You can see where the soundpost penetrated the top. But, the pieces are all there, I believe, and the breaks are clean. I told the customer if I could get the top off reasonably, I could probably put it back together, and put a surface patch over the soundpost area. Not the greatest for sound, but these things don't sound that great to begin with. It's something of an experiment for me, to see how it works, but so far so good.

The interesting thing to me was all the Chinese characters written in pencil. Some story or something. Done before the bassbar was installed. I haven't seen much of that in modern Chinese instruments.

The violin whose top I removed belongs to a 'mature' lady. It is a very modest factory instrument, that she wanted to get put back in working condition for her grandson. It belonged to her father. I could tell by the exterior arching, collapsing, that something was wrong. Inspection with a mirror and light showed that the bass bar had failed. This seldom happens, though it is often blamed for errant buzzes and the like.


Note the lack of corner blocks. The top has been off at least once before, at least to repair cracks, including the installation of massive cleats. This instrument may have had an integral bassbar, meaning that wood was left behind when the top was carved. The top shows some rather non-subtle tool marks, characteristic of an integral bassbar instrument. Sometimes, when the top is off, these integral bassbars are cut out, and replaced with a real bassbar. She wanted it repaired due to its sentimental value.


Here, I've slipped a piece of paper towel under the free-end of the bassbar. It appears that it was never fit well, which is probably why it failed. I removed the bassbar as well, and once I clean up the glue, will decide whether I can salvage this one, or, more likely, replace it with a new one.

Next-day edit: A YouTube video came up on a forum I read, which I'd seen it a few years ago, but didn't think of when writing this post. In it, you can watch a cello top being removed -- This Old Cello

Friday, November 6, 2009

Finishing the pegbox and scroll

With the box closed, it's time to get the neck ready. First to finish the pegbox and scroll. Here's the neck, cut-out of a block with a bandsaw, shaped with files and knives.


Then it's time to clean up the scroll, undercutting the volute, and adding a chamfer to the edges.


I've laid out the centerline earlier, before cutting, and it needs to be refreshed from time to time. The pegbox, the hollow area between the walls, where the strings wrap around the pegs, needs to be hollowed out. I use a drill-press to make a series of holes, with the depth set to avoid drilling through the bottom.


I start with a narrow "U" gouge and remove the wood rather quickly. One needs to be careful near the walls, as this maple is highly figured and it's easy to tear-out. With most of the wood gone, I then move on to a variety of gouges to clean it up. It is quite hard to get under the scroll, near the A-peghole, so there I alternate between a curved palm gouge and a thin flat gouge.


The fluting then needs to be done. This is the double channel you see wrapping around the outside of the scroll. With the centerline clearly marked, I use the small palm gouge to make a double track up each, merging into one at the narrow places. These initial tracks are joined by carving with a larger gouge, all the time trying to keep the centerline sharp and straight, and the edges safe for errant slips.



We are so lucky these days to have access to good information on classic violins. In the background of the previous photo, you will not the February 2009 issue of Strad magazine, with a much larger-than-lifesize photo of the scroll on the cover. To the right, is the poster of the 1715 "Titian" Stradivari violin, again from this same issue. By constantly checking the photos and looking at your carving from various angles, you at least have a chance of getting something reasonable.