"New" tool works pretty good

After using my 1" incannel gouge on the inside of the back I decided to try it on the outside. I usually use a roughing plane, but this gouge works really nice on the maple. Slices it up. Going from the center seam to the edge it cuts just with hand pressure, no need for a hammer. Old tool, new use.

This is how I rough the outside. I rough the edges to 5-6mm. Then I start whittling the center down. At this point I am still a little high near the ends, and quite a bit too thick in the middle, you can tell by how big the dots are in the middle. The point will only go so far in on the maple, it will go further on the spruce. If you push too hard on it you will make little dimples on the inside. I'm not worried about those because the inside is not quite finished. Real close, but not perfect yet. I move the thickness marker from 4mm at the lower bout up to 6mm in the c bout, in .5mm steps. This should leave it 1.5 too thick, and after smoothing up still about 1mm or so thick. When I get it to that point I'll stop for now.

A little bit on the back

I roughed the inside of the back out the other day. Took about the same amount of time as the belly did, about 2 hours. The back isn't as deep, but my plane didn't want to work, the flames were conspiring against me. I tried my Japanese incannel gouge and it worked like a charm. That gouge cuts with a slicing or paring cut. Cutting across the grain, from the edge to the middle, the flame didn't bother it. The only thing it needs is a longer handle. I usually like short handles, but this one, at 9.5" just seems too short. Should have bought the Gooseneck, but it was $30 more.
I always cut the violin shape out after roughing the inside. I can't see the shape or the thicknesses when it is a rectangle. I try to rough some of the thickness off the outside to make it easier to saw. On the belly I use my aluminum coping saw. On the back I use a bow saw with a Japanese blade. It cuts like butter. The blade is sold by Highland Hardware, along with the saw frame. I figured I'd save some money and alter the bow saw I had that came with shorter, not very sharp blades. Seems like the way I try to do everything. I had to make a new crossbar, and adapters for the attaching the bade on each end. After I strung it up with a scrap piece of maple for the tightening block I found the one that came with it. Oh well. As I said, it cuts really nice, but the smallest radius is not small enough for the form, so I do all the finish cuts with the other saw.
As far as I can tell the Red Maple seems about midway in hardness to American Sycamore (softer) and Black Cherry (harder). The flames in the maple are closer together, and stand out more, but the ones in the Sycamore seem deeper. The ones in flamed Birch are nasty. All said it is fairly easy to carve. Much easier than the Sugar maple and flamed Birch I've used.

Age is a good thing?

Yesterday I was figuring out the string angle on the "Titan". As I said before it isn't straight. Anywhere. Viewed from the side, the ends of bottom of the belly are higher than around the c bouts. The cross arch is 15.5mm but the effective long arch is only 14mm. This came about from age. Hundreds of years, or maybe only a few until the violin took a set, and the string pressure pulls up on the ends of the belly and makes the bouts fuller and the long arch flatter. What this does for the string angle is make it flatter. Drawn out using the measurements for elevation and neck step, the string angle should be 157.9 with the 15.5 arch height. Using the effective 14mm arch the string angle flattens to 158.9. Nothing else changes. The nut is still 4mm above the line drawn from the bottom of the belly, and the eye of the scroll is still right on the center of the line drawn from the bottom of the back. Even the angle the neck is set at stays the same. Everyone(?) seems to feel that flatter is better for violin string angles so a warped out old Strad is better than a new one.
I don't know about warped out old people, but are old people in general better than younger ones? I'm transitioning to the older side (I don't feel different) so my view is biased. I'll go way out on a limb and say....well I won't say. Old people, young people, it doesn't really make a difference. People are just different no matter what. What age does do is add experience, and with experience should come wisdom. But that is not a given either. Some people have life easy and everything always goes right for them. Others go off on the wrong track and never get back.
Both of them may not be living the life they could if just let go of what they want, and try to do what God wants. It's a hard thing to do, especially with all the other "priorities" and obligations you have. It's a hard thing to do if you don't know how to listen to the tugs on your heart, to the voice telling you to stop, to go, to wait. I try to live my life with joy and compassion, but slow traffic and long hours at work play havoc with that! But I try.

Marking out the Neck

I haven't had much time to do anything lately. My "real" job has been busy. I went from working afternoons for 8 hours to working days for 10 hours...with no day off. A couple months ago I couldn't find a job. Guess I can't complain. Being in demand is better than sitting on the couch. I almost have the back arching set, but I need some more computer time to dial it in. Tonight I was itching to do something so I marked out the scroll for the neck. I've seen pictures of scrolls on old instruments that have pin pricks around the eye. Seems like they used that to mark the neck blank with a template. Decided to do mine the same. I used my trusty light box, I think it is the same model that Strad used, and copied the scroll profiles from the poster on to a scrap piece of paper. I always save paper that isn't printed on both sides, or hardly at all for re-use. Then I made a fold along the top where the fingerboard sits and placed it on the wood. Folding the other side down I slide them to the line I drew for the nut and taped them in place. Using a push pin I punched the outline on the the neck blank. Now I feel in touch with the old masters. If I can saw it out to the line I will feel even better.

Looking more like a violin

While I was eating breakfast this morning I was looking at my violin belly. It's actually starting to look like one! I didn't do much on the violin yesterday, and probably won't today, but in about 20 minutes yesterday I rough sawed the outline and brought the thickness down to around 5mm. You can see how the inside arching generates the center of the outside arching. The recurve blends in from there to the edge. It is still as stiff as 3/8" plywood. I still haven't checked all the arches on the back yet. When I finish that I will rough out it to this point.
We saw an estate sale sign along the road yesterday, in a really nice neighborhood, and decided to take a look. Wow! I've never seen so much stuff. Collections of ornaments, collections of toys, collections of cameras and electrical stuff, more and more collections. Nothing they ever had was ever thrown out, and they always bought at least 2-3 of anything. I left there thinking I would go home and put everything I haven't used in a while in a garage sale, load up a small U-Haul, and we could move into a 600 sq. ft. cabin somewhere. What a waste. All that money spent on things. How much good could have been done with that money instead? I did buy a few things though....a brand new oil stone set, some twine, and a tower for starting charcoal. Maybe 600 sq. ft. and an extra large garage?

Roughing the Outside of the Belly

Today I roughed the outside of the belly. Took two hours. I started with my trusty wooden plane. I've heard that gouges are faster for roughing, but I have two problems with that. One is that my bench wanders too much for real heavy work. Rough gouging just doesn't work. The other is fear. I'm not afraid of much. Don't care for heights too much, but that's about it. But I don't want to have the gouge go in and tear out a big chunk while I'm hacking away with it in roughing mode. I've had a few close calls with flamed backs that just barely cleaned up. Some people I have worked with were always afraid of finish cuts. Take a cut, take another, take another, take another, maybe another and cross their fingers. I always put my trust in my machine, at least the ones I could trust, and broke it down into 2-3 cuts of the same depth and in most cases it worked. There were the few jobs where the boring bar was too flimsy, the steel too hard, or the part itself refused to cooperate, but for the most part it works. Since being laid off I've put my trust is God, not myself. I didn't stop looking for work, and always assumed the job I sent a resume in for was mine, but I didn't worry about it. It kept my sanity, maybe drove my wife crazy, but I have a job now just 8 miles from the house that is maybe not perfect, (what is?) but not bad. I'd like to be that sure of my gouging.
After I rough it down some with the plane I use a large, fairly flat gouge. It works good on the spruce, but is too flexible for the back. I need to buy something else for that. Any suggestions? I use a thickness marker like the one Stradivarius had to show the thick spots and I carve all the dots out of it. I rough it first to 8mm all around, then I change to 6mm and avoid marking in the area where the catenary curve starts on the inside. That area I don't mark and just blend in in the the marks up higher and the marks near the edge.
This is just roughing. I do this with the wood still a rectangle so it is easy to clamp. Now I'm ready to rough saw it. It is much easier to saw now when it is 6-8mm thick all around the edge. Then it will look more like a violin belly.

Inside of the belly roughed out

Here's the way I start carving a violin...with plane on the inside! In two hours I had the whole structure for the violin well on the way, with only a plane, a chain, and two rulers. I've gone as far as I can with the plane and will continue with a scraper. I have to smooth it up some and make sure all the cross arches and diagonals with the chain are just right. The plane has to be sized just right to work the way I like. It has to have the right curves, both lengthwise and side to side. It also has to be the right size. To big and it won't fit in. To small and it will let you plane where you shouldn't be planing. I made the body of mine bigger than I had it originally. The sole is 1" X 2.5" with a 11/16" wide blade. The body used to be maybe 1.5" tall. I made a bigger body that is 4" X 2" X 2" and glued the old sole onto it. It is much easier to hold now for heavy roughing. My fingers used to get tired, now I can grab it with my whole hand. The blade is O1 if I remember right. It stays sharp for a long time, but never seems to have quite as sharp an edge as I'd like. Maybe I need to spend more time sharpening it, seems quite hard. Maybe I'll give it a good sharpening before I start into the maple back. I haven't checked the arches on the back yet. It feels good to actually start on it, instead of just planning and setting up. Maybe I'll start carving the outside now, so it starts looking like a violin.

More planning

Before I start making chips I want to make sure that the plan I have is correct. Just thinking that your idea is right doesn't make it so. If I conclude that the outside cross arches are cycloids and the inside arches are catenary curves, I better be able to back it up. I made 13 cross arches using the long arches my curves came up with, and guessing at the width of them. Then by checking the resulting thicknesses across the whole width of the curves I can see if the widths I chose were right. So far I've moved them around some, but my first guess wasn't bad. My curves aren't drawn perfect, the programs I have won't talk to each other so they are drawn as splines. I don't think any curves I carve will be that perfect either, so close counts, as well as trends. I haven't finished the belly design completely yet, but it is close.
I've been a machinist for 30 years so I'm used to working with blueprints...plans to show me exactly what I have to do. Even then, sometimes the prints I get at work don't tell me the things I want to know, only the things the designer thought about. Violin makers have to make do with much less than I'm used to. I don't think that the old masters did extensive planning. Sure they had a plan, but it was simple, they did it the same basic way all the time, and the adjustments for wood stiffness was a natural part of the finishing up. It's easier to do something that you know how to do, than to figure out how someone did something when there is no one left to tell you.

Saved from the scrap heap

I sawed out a fingerboard blank from a 2 X 2 X 12 hunk of ebony the other day. Already made one out of it. When I started planing the radius on the top I found I had trouble. An inclusion. A defect. A hunk of scrap. I thought maybe planing it down a little further would make it go away. Kind of like the ostrich hiding it's head in the sand, only the planing made it worse. This is one of those things that, on almost a daily basis, bring to mind a story from God.
Take a look at people from Gods perspective. Everyone can look good on the outside. Trim them up a little, start to shape them to make them useful, and things can get ugly. Inclusions, defects, a hunk of scrap? No, something He shows us to become better people from. Something in our life that isn't easy, but in the end works out. He doesn't have to sweep us up and throw us in the trash can. He has a better plan
If you look at it from the people point of view it is a flaw in our character. Something we want to hide. When it comes out it looks even worse. And if others keep exposing it... well you get the picture. Trying to hide the flaws in our life is not going to work long. Sooner or later our anger will get riled up. Our greed will show through. Our love of self will be exposed.
The flaws in our life at least can be fixed. We can drop them off at the Lord's feet and let Gods grace fill the inclusion that has been carved out. What about this piece of ebony? I can make a tailpiece out of the bottom and maybe even a peg or two out of the top part. I'll throw away the inclusion, it doesn't need to be included.

Ready to go now

Well my wood order is finally down to looking like violin material. The back halves and belly halves are jointed, glued and the bottom is planed flat. The neck block is squared up to size. The ribs are cut up, but still a little thick. Ready to go.
I plane the long joints using my 18" Craftsman plane. I clamp the plane in the vise and slide the wood on the top. After much experimenting I found this works the best for me. I mark the edge with pencil and plane until it is all off. Then I hold both halves together and check the fit by seeing if I can see light through the joint. The perfect joint, or at least the one I look for, is closed at the ends and has a very slight sliver of light through the middle. I read that this type of joint helps keep some glue in the joint and it isn't starved. I put a coat of thinned glue on first to size the wood and then glue up with a full strength glue. I glue the belly as a rubbed joint. I lightly clamp one half in the vise and apply glue to both faces. Then I put the loose half on the clamped one and slide it back and forth. After a few slides it changes from slippery to stiffer and I slide it where it is supposed to end up and leave it there.
For the back I get it ready to clamp on my Workmate. I don't have a real workbench so it works as good as it can. The worst part about it is its main feature...portability. I don't really want it moving! It roams all over the basement when I'm planing, or gouging, or sawing, well just about anything. To glue the back up I put glue on both faces, slide a few times, and clamp it up.
I like to start out with a square block for the neck. I know the stock gets cut away, and it is a waste of time, but it makes it easier to mark out and clamp for sawing out. The camera isn't talking with the computer so I'll add the photo later.

Smoothing up the ribs

Now that the ribs are cut out it's time to smooth them up and bring them down to size. Rough sawn they are 1.5-2.5mm thick. I take some of the high spots off with a sharp gouge. Then I even those out with a plane. I have a low angle plane. It isn't much good for ribs. Actually I'm not too impressed with the plane at all. It's hard to hold. Hard to tighten the blade. The latch and lock for adjusting the gap ahead of the blade doesn't stay put, comes loose all the time. There is no way, except beating with a hunk of brass, to get the blade square with the bottom. The blade itself is already worn out because it just won't stay sharp. Most of these are design issues that should have been addressed before they even made the plane. I'll have to keep my eye out for older used block planes at garage sales. Haven't seen one yet, only newer junk. I could make it better. Turn a bigger brass knob for tightening the blade that is up higher and not hidden. Maybe make a bigger knob for the throat adjustment. A new blade is needed anyway. Brass or steel shims on the side so the blade actually fits square and isn't allowed to flop around. I already have the blade up on shims so the clamp doesn't bend the blade. They didn't have any support under the blade there. I don't have any idea what kind of blade I'd get. A2 seems to be the latest craze. I turned hardened A2 at work and it was the easiest of all the materials I worked with. It always cut clean so it might make a great plane blade. On the other hand, the blade in my 18" plane works great, stays sharp, and is just whatever Chraftsman used back before they switched to foreign manufacturing. Probably just high carbon steel.
Many people use toothed plane blades for doing ribs. I use my plane blades for scrapeing because they work, and they are stiff. I found by mistake that the one blade I have is too hard. When I tried to put a hook on it I could hear the metal breaking. What I found was it makes a great "toothed" scraper. That's what I use for roughing the ribs. Then I switch to a smooth one to finish them up. Sometimes
accidents are a good thing.

Saw out the ribs

I had a little time in the basement yesterday and managed to saw off one strip of maple for the ribs. The chunk I have is more than two ribs wide. I'll cut a few more up and then start finishing them. First I plane the top side smooth and fairly flat. The saw doesn't cut curves well, uh, except when you don't want it to. You have to watch both sides of the board to make sure the saw is sitting flat. The saw I used is a Japanese single edge saw (Kataha Noko Giri) with a .o2" thick blade that cuts a .03 kerf. Trying to save money I bought just the blade thinking the handle I had would work for it. It didn't. The blade fit in the metal slot, but the locking part didn't work. So I made a handle for it with a wooden latch that holds the blade in place and is lashed on with string. It works. The blade seems a little dull now. I don't know if I'd by it with the handle or just use my handmade handle. That is one thing about the mass produced japanese saw. The teeth are impulse hardened and they are rather brittle. I've thought about biting the bullet and buying one of the hand forged blades that aren't as brittle and can be reset and resharpened. Any thoughts on that? Let me know.
The plane I used cuts really nice. I bought it at a flea market years ago. Took it into the shop to true it up on the surface grinder. The grinder hand, who is also a woodworker took my project over like his own baby, and did it on his lunch break. It was ground with the blade locked in, but raised above the cutting surface. I made up an extra thick chip beaker that is 3/6" x 2 3/8" x 6". It makes the blade feel like it is welded right to the plane. You have to do some modifications to get everything to tighten up in the right place but I highly recommend tweaking your planes. A simpler way would be to use the Hock chip beaker. It isn't as massive, but is the same idea. Actually it is where I came up with it. The blade itself is just the old standard Craftsman that came with it. Holds up real well and sharpens easily. The only thing I don't like about the plane is the bottom is corrugated. That is fine for the ribs and the bottom of plates, but can be a problem for the center joint.

Making the mold

Before we start cutting on the violin wood we have to make a mold. The mold is the pattern the ribcage is built on. I print out the form I drew of the Titan violin back. It is drawn 3-4mm smaller than the finished violin plates. The ribs are about 1mm thick so that brings the 3-4mm down to 2-3mm. That is the overhang. Violins have a top block that holds the neck, a bottom block that holds the button, and corner blocks that make the ribs easier to glue in the corners. These are notched into the form. The end blocks I made for this one are longer than the others I have made. The original mold has cut outs for the blocks the same length top and bottom, and the Strad poster has a CAT scan of the Titan that shows the entire ribcage...with top and bottom blocks the same size. If it worked for Tony I'll give it a try.
The corner blocks are notched in with a little forethought. In order to cut the rough blocks into flowing corners that match you have to have some guide. Even using a paper tracing from your original drawing like Strad did, or printing out another copy from AutoCad and cutting it out like I do, it is still hard to line it up with the mold. A neat little trick is to make the cutout so it starts where the corner ends. You can take a straightedge and mark the blocks using those two points. I learned that on maestronet.com (thanks Michael Darnton) I also read somewhere on there that making the corner of the cutout for the corner blocks bigger than 90 degrees makes it easier to pry the finished ribcage off the mold. I did an exaggeration of that and found that if I take a line from the bottom (or top of the upper corners) of the blocks across to the other side it goes through the corner as well.
I saw the blocks out and get them ready to glue on. I have 3 spacers I place under the mold, on a flat table or board, so when the blocks are glued on, that side is pretty level. It also puts the mold in the middle of the ribs so there is space on both sides to glue the linings on. That side will be the back. The belly side may not be level, depending on the original rib heights. This one is almost straight. Bending a belly a few mm's here or there isn't a problem. Now that the mold is ready we need ribs.

My wood order is in

Here is the wood I ordered to make this violin. I was instructed to get "real" violin wood. The old masters got there wood from local merchants, who in turn got the wood from as near or far as they had to go to get it. The mountains of Europe was the source for the spruce, and the maple was either from there as well, or sometimes even more local wood. Now in the internet world, "local" wood is at the touch of a keystroke. I decided to buy my wood from Old Standard, a tonewood supplier in Missouri. That's fairly local. Their specialty is red maple and red spruce, also known as Adirondack spruce.
I phoned the order in and the guy on the line asked me what kind of wood I was looking for...how much flame on the maple? what kind of grain spacing on the spruce? how about red lines or irregularities? Almost like picking through the bin myself. I told him I was looking for something with fairly light flame. The shop owner had told me to get less expensive wood. I didn't need highly flamed stuff, just makes it harder to carve. Examining the poster I found that the Titan doesn't have spectacular maple anyway, kind of fades. The guy at the wood store said he had some mandolin wood that might fit the bill, they don't worry so much about flame as their finish is usually too dark to see much flame anyway! Looking at the wood it doesn't look lightly flamed at all. The better stuff must be spectacular. He set me up with a matching piece for the neck and a huge chunk to saw up ribs. The spruce looks nice, I actually like grain that isn't perfectly even, and he added a few strips for bass bars.
We're ready to make chips.

Back cross arch

Now the cycloid and catenary curves worked well together on the belly, but they won't work on the back in the C bouts where the thickness isn't even...will they? Yes they still work well together. The outside of the back can still have cycloid cross arches, and the inside is still basically a catenary curve in the beginning. The whole inside of the back and belly can be roughed out to an amazing degree of accuracy with just an outline, a couple of drilled holes (you could even get by without them), and a chain.
The outside can then be roughed to size and shape. In the beginning the procedure is just like carving from the outside first. Then I use a thickness marker to point out the thick points as a guide, so I don't go to thin. This will only work so far. This is because there is a fundamental difference between the two curves. The catenary is strictly concave (convex when viewed as above), whereas the cycloid is concave and convex. Through the middle of the instrument the curves are similar and the arching on the outside can go along quite close to finishing. At the point of inflection, where the cycloid changes from convex to concave you have to leave it thicker and blend in the recurve. This point is easy to figure out. From the centerline move out half the distance from the centerline to the low point of the arch and add half of the arch height. Coincidentally(?) this line of inflection is right in line with the f holes. All this will be easy to see when I start making chips.

Belly cross arch

Now I'll explain how I design the cross arching. Most makers use the 5 cross arch profiles, make templates and carve to suit. That's fine for those 5 places, but what about the rest of the violin? At risk of being called a heretic I'll admit I work the inside of the arch first. After defining the long arch I make scans of the cross arches, mark off the thicknesses and tape them on the light box. Using my chain as before I find how wide the original catenary cross arch was. On some instruments the catenary is almost the whole of the inside arch. Others have a lot of recurve, and the catenary curve may be a long ways in from the rib linings. Generally I've seen that in the C bout the curve ends up close to the linings. The upper and lower bouts vary with the model. By finding the widths of the catenary arch at these 5 points I can draw up a curve that blends them together. The outside of the cross arch is a cycloid, or a variant of one. If the maker had the right combination of arch height and width on the inside, the resulting arch on the outside will be perfect. Stretching the arch wider on the inside gives a fuller arch with less recurve. You can guess that a narrow cross arch makes an outside arch with a lot of recurve. Different long arch heights and shapes will work differently with different inside arch widths. It's all part of the design. If you find the right structure, on the inside, for the model you are trying to make, I'm sure the results will be better. The drawing shown here doesn't have the edgework, but shows the catenary on the inside and the cycloid on the outside. The thickness is 3mm at the low point of the arch and 2.5-2.7mm everywhere else. The area from where the liner is to where the catenary arch ends will be blended in while thinning and tuning the belly as a way of controlling the stiffness.

The back long arch

On to the back long arch. On the back I split from the idea held by Torbjörn Zethelius in his "Inside Out" article in the Strad, and came up with an idea I don't think is held by anyone. At least I haven't seen it presented anywhere before. I came up with this idea, and it was really solidified when I read that a viola by Grancino had a back 7.5mm thick. This was the only way I could get that result. The Ole Bull model I made has a 7mm thick back, and is the direct result of how the long arch is formed.
If you make a catenary curve from the end block to somewhere between the far corner and the opposite bout, from both ends, you end up with a shape like two clam shell halves joined in the middle with a thick rib. When you add the back thickness to this arch you get the outside arch which is... a circle. You can change the thickest point of the back by changing where you decide to put the end of the curve. Putting both at the corners will give a thicker back and one that rises faster. Putting both at the bouts works better for a low arch like this Strad. Some models may have the top and bottom arches going to different points. I take the arch given on the poster and copy it on white copy paper with a scanner. I tape that on my light box and then mark the thicknesses and end blocks in. Taking my chain, I move it around until the curve goes from the block to wherever, and goes up to the thickness marks. I mark the end point. Then I do the same to the other end. I find the center of each curve, and the depth at theat point and the long arch is figured out.
The drawing shows the circle in black, catenaries in orange and the outside arch in red. The bottom is to the right.

The belly long arch

Now we are on to the arching. I was going to do the cross arches first but I don't have the curves drawn up, so I'll start with the more controversial long arch. Controversy on a design 400 years old? Yes. Almost every facet of violin making has more than one way of accomplishment. From grounds and varnish, to inside arches and outside arches, there are camps divided, and pitted against each other holding their views close to their hearts, and in secret if need be. I take the pragmatic approach...I do what seems to work.
Whereas the outside cross arch is, for the most part, deemed to be something close to a curdate cycloid, the long arch isn't. A curdate cycloid is the curve you get when you roll the wheel of a Spirograph along the straight gear. Some like to say the long arch is a cycloid at the ends. Others insist they are circles. I use two different, but related forms, one for the belly, another for the back.
Let's start with the belly. There was an article in the Stad magazine a couple years back that confirmed an idea, or at least made me a little less uneasy knowing I wasn't the only one thinking that way, that the inside of the belly arch was a catenary curve. A catenary curve is the curve a chain forms when held at each end and left to naturally fall in the middle. But it isn't just a simple catenary. The ends of the violin body are only carved on the inside up to the end blocks. If you draw a line straight across form the end blocks to about 10-25mm from the edge of the plate you will end up with the top line shorter, again by a simple ratio, than the bottom line. The catenary curve goes on a diagonal from the ends of the lines by the blocks. Where the lines converge is above the centerline of the violin. The cross arch on the inside is a catenary as well and they are carved in to blend with the diagonal arch. The affect of this is to make the curve on the centerline of to belly deepest at around the bridge line. Over years the violin will get pushed down at that point from the string pressure and will bulge slightly at the bouts from the ends being pushed in. The outside curve that results from adding the belly thickness is an ellipse, that is slightly higher near the bridge. So it isn't really an ellipse, but is very close.
The black line on the drawing is an ellipse. Red is the outside arch and orange is the inside arch.

The Form

The first step in making a violin is selecting the pattern. If you want to make anything you need a plan. The shop owner suggested making a Strad, so Strad it is. I have a few posters of Strads, The Milanollo, the Viotti, and the newest one, the Titan. I've figured out the Viotti before and decided to make a go of the Titan.
Violins, at least Cremonese violins, are build from the ribs up on a mold. The mold is a piece of wood, cut to the the outline of the violin, and blocks of wood are glued on it that become the corner blocks and end blocks. The mold helps form the shape and facilitates gluing the ribcage together. Stradivari used many different molds in his long lifetime. The Titan is said to be made on the P mold. If you have ever tried to make an outline of a violin, measuring the lengths and widths, and connecting arcs, you know it is harder than it looks. Adding to that, violins are never symmetrical. The Titan seems to be the worst one I've seen yet! Even the archings are way off center. I made my mold drawing on AutoCad (because I have it), using dimensions I found online. It fits the Titan on one side, sort of, then you have to cock it on an angle and then it sort of fits the other side. I'm happy with it. All of the dimensions are related to each other with simple ratios...3/5, 5/8, 1/3, that seems to be the way things were done in the period. I've found that every violin I've drawn up has a certain structure to how the f holes are placed. No maker does his the same as anyone else. Some even change their structure from pattern to pattern, or just to change it, but it is always there. Don't just copy the f hole dimensions, try to figure out the underlying structure for the placement of the terminal holes. At least that might look right.