Posts Tagged ‘neck mortise’

Scroll, pegbox and Neck-set

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Scroll and Pegbox completion: and Neck-set

Scroll and Pegbox Completion:

When I last posted, I had just temporarily attached the fingerboard to the neck, but had not carved the pegbox, nor the fluting on the back and top of the scroll. In the past I have completed those before attaching the fingerboard, but this time I was anxious to get going, and it seemed a good idea at the time….

So…I first shaved the fingerboard sides to fairly closely match the handle portion of the neck, and then began carving the pegbox.

Carving the pegbox.

Carving the pegbox.

 

Carving complete: scraping and filing to follow.

Carving complete: scraping and filing to follow.

 

Then I could complete the outside of the pegbox, finish tapering and scraping the handle portion of the neck, and carve the fluting on the scroll. I still had the centerline I had scribed when I first cut out the scroll, so I worked from there, and tried to “color inside the lines.”

Nearing completion.

Neck is nearing completion, outside and inside of Pegbox are pretty much complete. No fluting yet.

 

Fluting nearing completion...back view.

Fluting nearing completion…back view.

 

Fluting nearing completion: front view.

Fluting nearing completion: front view. Lots of scraping left to do.

 

Neck Mortise

Before I can set the neck, I have to lay out the exact footprint of the neck heel on the centerline of the corpus, where I will cut the mortise through the ribs and into the neck-block. I have deliberately left the heel long, so that I can set it through the neck-block, and not have to worry about fitting against the back button, because I haven’t installed the back plate yet. I will trim the heel afterward, and, when I level the back of the corpus, just before installing the back plate, I will level the heel right along with the linings and blocks.

So here is how the neck mortise went:

Mortise layout

The mortise is laid out off the centerline, which you can barely see in this photo, because one top rib nearly obscured it.

 

mortise beginning

First, I removed the rib ends, and double-checked my layout lines.

 

Front plate cut out.

Then I removed the waste wood from the edge of the front plate.

 

Mortise carving

Then I began chiseling away the block wood, to open the mortise.

 

Neck-set

The mortise has to fit the neck in every respect: It has to be the right width and shape, so that the neck goes to the correct depth. (I wanted a 6mm overstand at the edge of the front plate.) It has to be the right depth so that the distance from the front edge of the nut, to the top of the front plate will be exactly 130mm. The sole of the mortise has to be flat, so as to fit tightly against the end of the neck, but at the correct angles, both laterally and fore-and-aft, so that the neck is not twisted in relation to the corpus, the centerline of the neck is in line with the centerline of the corpus, and the projection angle is either exactly right or just a shade high. I have had instruments change fairly rapidly after they have been strung at tension for a while, due to the top bulging a little as it is compressed by the string pressure, so, I deliberately set the projection angle just a tiny bit high, anticipating that it will change a bit under string tension.

Dry-fit neck-set.

Dry-fit neck-set. No glue, yet. Just the final check of all measurements and angles.

 

Dry-fit check of overstand mark and neck length mark.

Dry-fit check of overstand mark and neck length mark. Both are correct.

 

When I am finally satisfied that all is correct, I remove the neck one last time, slather the hot hide glue into the mortise, and shove the neck home for good. I quickly check all measurements, to make sure I got it in correctly. I only have a few seconds before that glue sets up permanently. Fortunately, all was still good, and I applied a single clamp to hold it until the glue dries.

Neck-set, glued, and clamped.

Neck-set, glued, and clamped.

 

What’s Next?

You can see that I have about 10mm of extra heel hanging out behind the back of the neck block. I will saw that off, nearly flush, plane it as close to flush as I dare, then, after removing the mold, installing the back linings, and trimming the linings and blocks, I will level the entire back of the corpus, including the heel, on a “sanding board.” When all is perfectly flat, I will install the back plate, and the violin will begin to take on a life of its own.

For some reason, after I close the corpus, or thereabouts, I cease to see the instruments I make as a “project I am building”, and simply see them as an instrument I am working on. I am working on a violin, at that point, not just something that will become a violin. It is a strange feeling, but it has happened on every instrument.  A student, who built his first instrument under my guidance, put it another way: as the instrument came together, he suddenly said, “This is getting real!” I knew exactly what he meant.

Next time I will remove the mold, install the back linings, shape the blocks, and maybe get this thing closed up!

 

Thanks for looking.

 

 

 

 

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3/4-Size Violin Neck-Set

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3/4-Size Violin in Progress. Purfling and Neck-Set

Purfling first, then Neck-set

When I last posted, the fiddle looked like this:

Purfling Slot Incised

Purfling Slot incised, but not completed.

 

Installing Purfling

This next step was to go back over the incisions, cutting them to the correct depth. Then I used a purfling pick (there are many different types) to shave out the waste wood from between the incisions. The last thing I do, before installing the purfling, is to go all the way around the slot, checking the width and depth with a scrap of dry purfling. I want the fit to be snug but not tight, and deep enough that the purfling will be flush with the surface of the plate. Here is the completed slot:

Purfling slot completed

Purfling slot completed

 

I used a bending iron to shape the sections of purfling, installing the Center bout sections first, and mitering the corners to form the desired “bee-stings.” As I cut the ends of the upper and lower bout sections, I have to check and be sure that the two mating miters will form a single sharp point, shaped exactly the way I want. This takes a good deal of practice. As one of my teachers told me, “Sure, this is tough! If it was easy, everyone would be good at it!” (Funny, that seems to be true in most walks of life…) Once the purfling is all in place, dry, I can begin gluing. Here is the dry fit:

Purfling Dry-Fit

Purfling Dry-Fit

 

Next I pry up the center of each of the center-bout strips, and, using a thin palette knife, I slip hot hide glue in under the lifted purfling, then, working quickly, I push the purfling back into the slot, and drive it home using a special tool. I start at the center ans work toward both ends, so that the glue being forced from under the purfling is driven along toward the ends of the center bout purfling strips, into the mitered corners, so that it glues the ends of the upper and lower purfling strips in place, as well.

Here is the freshly glued purfling, driven as deeply as I could manage, into the slot:

Freshly Glued Purfling

Freshly Glued Purfling

 

Freshly glued Purfling Detail

Freshly glued Purfling Detail

 

The next step is to sketch in a line 40% of the distance in from the outer edge, toward the purfling. It is a faint pencil line, but it serves as a guide to show me the limits to the channel…the broad trough around the edge of the violin:

Edge Crest boundaries inscribed

Edge Crest boundaries inscribed…it’s a blurry photo, but you can see the penciled lines.

 

Then I begin cutting the channel: a trough whose outer edge is the line I just inscribed, but which cuts only as deep as is necessary.

Beginning of the channel. The Edge crest is still visible.

Beginning of the channel. The Edge crest is still visible. I have just begun to cut the channel.

 

Purfling Channel Completed

Purfling Channel Completed

 

Purfling channel Detail

Purfling channel Detail

 

Neck-Set

I laid out the neck mortise, using pencil and straightedge. Then I cut the edges of the mortise, using a razor-saw, and carved the wood away to form the mortise. It is somewhat tricky (like all the jobs in lutherie), but I got it done. Once everything was perfect, I glued the neck heel into the mortise, using hot hide glue:

 

Neck-Set Front

Neck-Set Front

 

Neck-Set Side

Neck-Set Side

 

That was all I did that day. 🙂

The next step will be to remove the mold and install the back linings to the ribs.

Thanks for looking.

 

 

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