MIMF

This is a pretty slow forum, so it might just work fo a build post. I only work on things in the afternoon, so I don't get things done quickly. And I have lots of projects finishing up, and a guitar that is in the early stages too.

I thought I'd show the way I work. I'm not normal. Many of the instruments I've made, I came up with the idea and the plans. I often work from small photos.

I made a 5 string violin/viola after drawing up a cello pattern half scale, and seeing that the stop was about 195 mm. Super wide violin with a huge lower bout? Why not a 5 string. It came out cool. But the other day I saw that I drew up a violin pattern of a Maggini that I saw in 2 Calendars that were a supplement in The Strad magazine. A long, skinny thing. It has the same look as the 5 string that is based on a Maggini cello. I have a piece of quartered Padauk left from half of the board I bought for $40 or so. I should get 2 small guitars (the one I've started, a 1828 Staufer with the brass panel over the tuning machines, and adjustable neck) and 2 violins or violas out of it. I have a piece of Port Orford cedar for the belly, that I have room to cut slices off to make tops for a couple Strad based guitars in G. One of the projects still finishing.

Anyone interested? It might keep me more concentrated on finishing! I draw them incorporating the f holes into the arching pattern, and using ratios. It seems to work. I also start on the inside, and even did my arch top guitar that way. It came out nice too, and I can PLAY it, while the violins hang there silent. These are the plans, and what the inspiration was. The 5 string, and the wood for the violin.

Besides my choice of wood, "real" makers don't like that I start with the inside arch. It might be a Brescian arch, I don't know. I wasn't taught. Doesn't stop me. But before the arches, you have to draw it up. You could use posters from the Strad, the latest ones are really cool. but if you see something that catches your fancy, like a big Maggini, or a Gagliano viola? You have to find a picture, and make it full size. Enlarging isn't gonna work. You have to figure it out.
The measurements they give on posters give the length, and the widths of the bouts. Helpful I guess, but the round parts there are not well defined points. Were IS the wide spot? Is it the same on each side? I like to do the corners, the points of the purfling, first. I found that every one that I drew up, the dimension from one diagonal to the other on the bottom line is a ratio of the overall length. ,577, .6, .618, .625. Some real ratio. At the top it is a ratio of the bottom. The Maggini is .577 at the bottom, and .577 squared, or 1/3 at the top. Cool.
The distance down to the upper corner is often 1/3. The lower corner is about .6. When you get an oddball like the Maggini it will probably be something different, I haven't checked it.

The wide spot is often about 4/5, or .809 which is the golden number/2. The width of the upper bout is often 4/5 of the lower bout width. Play around with them, and you can sniff them out.

The f holes make a triangle, The apex is often the same distance up from the bottom as the lower holes are from the top. Often .618. but not always.

After getting the drawing the way I like it, I figure out the arching. For the long arch on the belly I do something different; cross arches. Combined with catenary cross arches it creates a curve across the center that is fairly flat; flatter than a straight catenary. To find where the diagonals go, I use the upper terminal holes.

I draw a horizontal line at the upper and lower blocks. This is the end of the arch. It could have some recurve on either side of the block; but why? Lines from the center of the blocks through the upper holes to those lines gives the corners of the diagonals, and then they are drawn in. After carving them in, the cross arches blending into them create an arch that reaches its maximum height around the area of the bridge. Right where we want it.

The back is different. It has a thick point. Some place it high, some place it low, some in the middle. The outside I make as a radius. I determine the height of the arch, and find out what radius will make it. Locate the thick point, and draw it in. Turn the drawing so the radius is on the bottom, and tape it on a window. Find arches form both sides that follow the radius pretty well, and then drop to the thick point. They usually end either at the centerline of the bouts, or the corners. After doing the radius on the outside, the cross arches on the outside, follow the thicknessing. I try to get a nice even drop all the way around the center bout.

I made my first guitar, an arch top last year; finished it a Christmas, and started to learn how to play. I did the arching for it the same way. I know it isn't normal but it looks cool, and sounds great with nylon strings; I did put carbon? strings on the trebles for more treble. I'll show photos of that showing the arching, and then drawings of the whole concept.

questions?

What a great essay! Thank you

Saturday I glued up the pieces for the back and belly. Yesterday I roughed out the inside of the belly. The plan is to be a little under 15 deep on the cross arch I went about 14mm. It is just rough for now. The Lei Neilson convex plane works perfect for violins and violas for finishing this. Small violins might need the large finger plane to get in some spots. Even this one, the middle near the ends is a bit difficult. I use the largest finger plane with the blade stuck way out for hogging the inside. It works great. I use scrapers from now on.

I use a 24" chain to check the arches. It's long enough for an arch top guitar. but the plane itself does a good job.

Then I flip it over, and use a big hogger plane to rough the edges down to 8 mm. Then I prick it on the outside with my Stradivarius thicknessing machine. I don't know what it's called. You adjust the height you want, and place the violin on the post, and prick the other side. use a plane until the dimples are gone. I start at 8, then 7, 8 5.5, and 5. I mark the outside with the line where the arches on the inside go to. I don't put dimples on either side of the line for about 5-8 mm or so, because that area will have some recurve on the inside.

Then I cut the middle area down to about 4mm. This one I went to 3.5 mm in some spots because the stock wasn't there! I have a poster of a Maggini, and it is 2.3-2.7mm in the middle there, so it is fine. Then I cut it out to the profile PLUS a lot. The ribs aren't even thicknessed yet, so the outline is not set.

This is where I leave it for now. When I come back to it, the first thing I do is make the bottom flat, and clean up the inside so the arches are good, and then I cut the f holes in. I check weight and tap tones for fun. The tap tones sometimes don't drop much at all. The shape and arch is there? I don't know. The last one didn't change much at all. The weight is 125 grams, sot it has about 40 grams on it or so. The ring note is about f on the first string of the guitar. The low sounds like low Bb. So 340/120. Oh, I found the REAL ring tone. It's G#, 415. That's pretty high still.

I thought I could get the back done today. Nope. I got the inside done (roughed close to size) and the outside is down to 6 mm thick.

I noticed today that I drew it up on an outline I had of a Long B pattern Strad mold that was done by Addie (he was on Maestronet). There are a whole bunch of patterns that he created and made available. The Maggini is a little longer on the bottom, flatter at the top and bottom, the curve from the bouts to the corners is way bigger, but the c bouts and corners is almost identical. Weird.

The two long arches with the high placement of the thick point gives an interesting shape. Like a solid state two unit speaker. Maggini had no inkling about speakers, or solid state in the 1620's! The upper knot in the top in the middle was there, but it doesn't go through to the outside. I figured it is 9-10 mm deep there, so it would disappear. It's almost gone. The one in the lower bout wasn't there on either side, It's a lot smaller than it got. The all look real solid, I will patch that one.

I got the back roughed out today. I get the edges to about 5 mm, and then work on getting the long arch to be a radius. I have a few radius gages that I made up. Once that is done, I round the sides down about half way to the edge, and blend to the edge until it looks sorta like a violin. Most of the stock is on the edges and recurve.

It's 178 grams now, and the ring tones are low A, F#, and f# on the guitar. Where's the D? The f# on the high e is faint. It wants to ring, but it is too stiff.

So now the front and back both have about a third too much wood.

I have the blocks on the form now, and have to work on the ribs. They are cut out, but need to be split in half widthwise, and thicknessed. I'm using a skeleton mold that I saw on Andrew Carruther's site. This will show how it works better than I can explain. https://www.andrewcarruthers.com/skeleton/

I drew out the string angle, and neck placement, and tailpiece plan too. I make different instruments all the time, and I like to know how the neck should be to get the overstand, projection, and string angle to somewhat normal numbers. I'm already way out on a limb doing a larger instrument, with strange wood; at least it should "feel" like a violin.

I make the heel of the neck at 90 degrees, and let it into the block deeper. Why not? I used some really dry, light yellow poplar I found in the scrap bin where I used to work. I'd check it once in a while, and found a bunch of neck and rib stock; curly cherry, walnut, curly maple. I'd look for color and curl.

I put this post in yesterday; at least I thought I did. When I look this morning it wasn't there. Maybe I wasn't signed in? But how could I write a reply? My computer keeps logging me out of forums. Security. If people weren't so EVIL, we wouldn't need it.

I bent the ribs Saturday. The four on the bottom weren't too bad. It is flamed Padauk, and the flames are quite hard, and want to split, but not bad with the darker side of the board. The light side is different. It doesn't have a waxiness too it, and wants to snap crossgrain. Nice. I cut the guitar ribs that are from the same board down to height, and cut a couple pieces for the UB ribs, and got them to work. The one has a split on it right where the flame is. It is almost like checking; but crossgrain.

Is there such a thing?

I had the guitar ribs at about 2mm thick. I tried bending a piece at that. Yeah right. I made the waist 1.5mm the UB 1.7mm and the LB 1.8mm, and it worked. Some spots on one side WANTED to pull away with the flame, but all in all I'm very happy with it.

Yesterday I glued the C bouts on. They have enough spring in them that I didn't even need to clamp. Brush on some HHG, and snap them in place. With the pattern right on the work-board, you can be sure that the profile I good. They ended up pretty close, even flipping it over on the other side. Cool.

You can see that there is plenty of room to put the linings on both sides; taper them, and you can even mark the inside of the lining area on the back and belly when you draw the outline on.

I got the ribs all glued on now, and have to put the linings on. I wanted to get the scroll started, I need a new 1/4" bandsaw blade. I left the tension on the other, and it was already messed up because I didn't know it had adjustments for the side. I thought I read how to set it up. Duh.

So I squared up a block that I found in the scrap bin where I worked. I'd look in once in a while for flame or color. This is nice wood, but it seems hard. Another is this hunk of cherry. The maple? is .65sg, the cherry is only .54. I haven't made up my mind yet.

I have to figure out the arching some too. I don't have a poster for this, and it is way different from the Maggini poster that I do have. They are about the same length, but the one I'm making is a lot narrower.

I glued the linings on, but haven't trimmed them yet.
With this method, you can mark the outline and the line of the linings. With that, I can tell that the bouts can be pretty much a curate cycloid arch on the outside. Between the corners it will rise faster, but on a belly, the f holes change things anyway. This inside is done, but the recurve will be added in.
On the outside, the center part is pretty much done. I will tune it after, but that shouldn't change it much. I will draw the f holes on, and do some shaping, then cut them out, and start finishing it up.
On the back, the inside is complete. I made the arches go out close to the edge, and just rounded them in. The arch on the inside of a back is much lower, and not as much recurve anyway. A Maggini is supposed to be really full.
Working on smoothing up the radius on the outside, I couldn't get the center to blend. I found out that the 15.5mm back I thought I had was only about 14mm. I knew it was close, but it must have been glued somewhat out of square. It will work ok. The back doesn't really do a whole lot. The long arch is in, and now I'm just blending the cross arches in. The sap pocket on the lower bout I will patch from the back, and leave the scar on the front.

I carved the back down more, and used my profile gauge to see what I have. This is the result. Pretty close to a curate cycloid. A curate cycloid is easy to draw. You only need tho know the high point and the low point. Then you can calculate the mid point, vertically, and the points that would be midway between them; like when the circle going on the line gets to 45 and 135 degrees.
At the midpoint add half the act height, low point to high point, to the distance from the center. Let's say the arch is 100 X 10. The center was supposed to be 30 mm, and the arch height is 10 mm, the center will be 35. The point between there and the center would be 15 mm plus 70% of 5, so 18.5 from the centerline. It would be 30% of 5 mm down from the high point: or 1.5 mm down; 8.5 The point between the low point and the middle would be 1.5 mm up from the low point, 1.5, and would be 45 plus 70 % of 5, so 48.5 mm from the center.

I have those points marked on the tracings of my arching. They are close. It is somewhat bigger, but not terribly off. From that I worked on it for a couple of hours, and came up with this. Probably close enough to put purfling in.

Now to work on the belly. I make some tracings of the arching, inside and out. The paper I'm using has the tracings I made at this same stage of my arch top. It lets me see how much recurve has to be added on the inside, and you can check the cycloid on the outside.
On the belly, the center area is pretty well to size, a few areas show up as being a little high still. I think the thicknesses are still too thick, but I want to tap tune it; not free plate, put an area tuning thing. Let's say you want to be about 2.5mm thick. You are at 3mm. If the tuning is close, maybe it is just a little high in the middle, you can take a lot more stock off the inside, making the arch stronger, than if you take it off the top, making it weaker. Once you get the entire plate even, except for the area of the purfling, and a little up from there, any final tuning will be on the outside only.
I draw the f holes on now, and do some modeling around them blending them into the arching, so they don't just look like they were arbitrarily thrown on without actually being designed in. Once I have it pretty well tuned in, I will cut the f holes in, and model, and tune things some more. For now, the f holes are just on.
Man, I can't get the color right at all on that. 3PM, and I need the lights on with a large doorway right there! Here's the old school B&W, I had to turn everything way down.
I'm trying to straighten out the back. Carving the edges down gave it a case of potatochipitis. The sides curled up. I put some water on the inside through the center, and on the outside around the edges, and clamped it to a piece of plywood. We'll see if it works.

You need to get control of your shop's relative humidity.

That hasn't changed in weeks. It's been 41-44% and 57-60 degrees. Oddly, upstairs it has been 46-50% and 67-70 degrees. The sump pump is even running now for the first time since May or so. In the summer the dehumidifier kept it at around 50%, and maybe it got up to 68 degrees. I dumped it every day until the end of October, but it was never full.
The Port Orford Cedar belly is still dead flat, even after planing the edges down to 3-3.5mm today, taking 16% of it as weight off.
It seems like it is usually the backs that do it. Often they both stay flat.
My archtop guitar hasn't seemed to move at all since the spring when I made a new solid bridge after I switched to nylons. But I don't play good enough to notice action! I did have to file some off the top two frets on the high e, as the nut was a little low. I did notice that. I leave it upstairs now. I had it in the basement in the summer.
I don't know. No matter what it will glue on.

I discovered that even though your humidity levels might seem stable, if you let your shop's temperature vary a lot when it cools overnight, your can have instability in your wood. This is because there is a direct link between temperature and humidity. So I usually leave an air conditioner (or heater) running at a low level to lessen the highs (or lows).

I have the f holes cut in now, and started getting it to look more like a violin belly. You can do a lot just by feel. I use a thickness gauge I made to check. I have the most problem with purfling not being in deep enough; or leaving too much stock on the end, and craving the purfling out. The edges need to be thinner than I think.
I tap it with a pencil and find areas that are stiffer too. I go until it gets even. I do this with the edges clamped to the table, not free plate.
I still have a ways to go, but it is getting there.

I worked on pushing the low point out to the edge. I usually leave more stock on the edge, but then I sometimes have the purfling disappear. I don't like that. So this should help. Just doing that flattened out the back. I already wasn't too bad after just sitting on the bench. The basement is still hovering at 42% and 56 degrees. Plus or minus one or two.

I might try to use the StewMac Dremel tool guide for the grooves. I used the Dremel, (actually, I used a Force rotary tool that I got free as a bundle from Woodcraft one year. It actually seems stiffer than the Dremel!) for the wild purfling on the 5 string, but I marked it out with the knife, and cut it freehand. The nice thing about using the rotary bit was that the bottom of the groove is flat. It isn't always so doing it with the knife. I did a small part of a line at a time because I found that it got flimsy if I cut the entire thing. Not a good feeling when it is all glued together! I'll try it on some practice pieces first. Maybe do the outside line, glue the purfling in, and then do the inner line. I'm not putting any design on the back of this one. The wood itself has ENOUGH going on.

I marked the inside of the inner groove, and the outside of the outer groove to see how they come out. Especially in the corners. A little bit of filing, and the edge works out right.

Boy, I need to take photos more often. I really need to work on my fill! I have a few instruments that I re-varnished, or added more too, and need buffing down, this is one of them. My varnish is pretty thin.

The StewMac purfling guide for the Dremel Tool worked great. I have a 1.1mm bit. The purfling measures 1.25/1.3mm. It fits tight in some places, and is a little too tight in others. I have a broken flat file the takes care of that. Better small than loose. Some might be from runout; but think about how you are going around the instrument with the guide. It has a convex radius on the base that rides against concave and convex radii on the violin. If it isn't perfectly perpendicular to the point of intersection of the radii, if you go around more than once, like I did; it will be wider. The corner radii on the c bouts was fairly close to what was on the base, so it just swung around in place. I liked doing it. You do have to cut in the points in the corners, and the part under the button on the back. Cross grain on a back is never a problem anyway, so that is easy.

I have to remember that the belly grooves need to be a little looser. The back doesn't swell as much with the glue, but the belly get wet with glue, and the grooves shrink, so you have to be sure the purfling is seated.

I glued the purfling of the outside set first. When I got done, I noticed that both the back and the belly were bowed upwards; along the grain; not the cross-grain potato chip curve. Odd. Never had that before. This morning it is all gone. Weird. I usually do the purfling when the body is all glued together.

For the weight and tap tone people: Mode 1 and 5 on the back is low F# and just above Eb, below the high e on a guitar. The belly is one note off each way at F and e. The belly will get a bass bar, and that usually raises it some. It isn't really that flexible yet, so we'll see. The weights are 70 and 106 grams.

This is probably where I'd call it good before. I didn't have the 5X magnifier, and even after I got it, I wouldn't use it for cleaning up the finish, I was just glad to be done! Glue it up, put on varnish and strings and it's done.

But the finish shows EVERYTHING.

I found, after using the ground technique by the guy who runs the Chicago School of Violin Making now; Antoine Nédélec; who was a presenter at one of the MVA meetings. He has his violins in a light box for weeks, gaining color. He uses chemicals to help speed it along. I did that on my last 2 violins. I used ash water/lye and tannin water/using Cherry chips. I noticed when I brushed on the water, and put it in the light box, I did get some color, that finally built up, (whereas before I wouldn't get any color in the wood from the Lightbox) but besides that; every flaw was magnified.

Horror of horrors.

So that's what I did yesterday. This is just overnight in the garbage can in the garage with 4, 20w black lights. Not much, but it looks worse than it did. The color is better, but the finish isn't. You can tell that I did the bass side first; it's almost presentable; and gave up on the treble. I'll work on the treble side first today.

I'll set up the Dremel, and cut out the one section of inside purfling that got messed up. The Dremel should make that easier, if I can get the distance just right. Faced with cutting that out with a knife I would say that it is good enough. Really; I wouldn't lie to you. That's the way that I am.

I replaced the small section of purfling where half of it was missing, and smoothed up the edges. It looks better, but you can tell that something was changed. I didn't know it until I finished the inside purfling on the back, but the last few pieces of purfling I had were not the same as the rest. The belly has all thin whites, but the back has some wide whites. I kind of like the look of the wide white. It looks like two thin black lines on the belly, and looks like a large white line on the back. Anyway, it doesn't match.

Oh well. Everything worked good except for that one corner. The purfling on the back came out good, and the edge work looks fairly good. It is harder to see under the lighted magnifier because of the color of the wood. I'll go back over it for days probably.

The belly is 66 grams, the back is 99 grams. They are both slightly below low F on a guitar for mode one, and slightly below high e on a guitar for the ring mode. The belly still needs a bass bar; so that will probably raise the tone? We'll see. The back will now have to get a couple patches on the inside.

First, I need to patch behind the sap pocket in the lower bout. It goes through all the way. It seems solid enough, but if the sap shrinks, and falls out I'll be left with a hole. Don't need that. I patch it so that the pocket shows. Battle scar. Then I have to back up the small crack coming from the upper treble corner. Some spots on the light area of the wood had this the further to the edge of the board that you got. The guitar back and ribs doesn't have any of this, and only the one spot on the back, and one spot on the ribs of the violin from the same section of that board has it. I will glue a piece of linen on any spot I see on the ribs that is questionable. I think there is only one.

So bass bar and patches are the next thing.