Inside First

[Ken_N]

Well; this one is on the back burner. I have the scroll about done and need to saw the sides down and cut the circle thing in front of the pegbox, and I decided to trim the top of the bass bar some. Is that a crack? Yes! Looking around I see  more. All of them are in the soft wood. I've had wood split on the grain, but never crack in the grain. Apparently it was not destined to be a cello belly.

I have a whole bunch of pegs to make, and a couple tailpieces and fingerboards. And put together a fancy little 8 string guitar in A.

That should keep me busy.

[Ken_N]

I like roughing things out in the winter. It is cool to cold in the basement. It isn't bad if you are working. I have boxes that I put "kits" in. Most have two instruments in each.  One is left over. You know how left overs are? Maybe you will do them, maybe you won't. Sometimes something new is fresh, and more exciting. This is the old box:

A Gofriller and a Montagnana. I've done both before. The Montagnana has a very high arch, and pointy corners. The Gofriller is more normal. But the wood choices? Koa and American Sycamore?

I split a piece of maple into two backs, and will have an Englemann and a Sitka belly for them. I think that they will both be the Vieuxtemps del Gesu. I haven't really looked at the arching yet. 

 

I have a smaller Storioni viola plane I drew up from a book. It is in box number 3:

 

I decided to make two, and one would be with much lighter wood, so besides the maple, very shiny mahogany, and box store cedar!

 

The last box is another from a small photo. I have the Guadagnini viola poster, but I don't care for it. It is a little shorter, and it does the look in! I has a rather nice piece of wood, and the belly is like curly Sitka. The maple is thick enough that I'd like to take it to the millworks, and have a 4mm thick slice cut off the bottom. It is big enough to do a one piece early 19th century guitar.

 

Now, what to play with first?

[uncle duke]

16 minutes ago, Ken_N said:

 

Are those flat sawn halves?

And what is the easiest way to deal with potato chip curling?  I've got one that decided to do so for one reason or another.  

[Ken_N]

The top is quartered on both sets. The bottom isn't bad on one side, the other is slab. Just crazy grain. One set looks like the best option.  I bought it as one set ,so if I get one I'm happy. At least there will be less chips! I'm trying to use what I have up. 

I have some wood for early 19th century guitars; sub parlor size? I like the one I made. It needs to be sawn, so I'd do the big slab at the same time.

I DO have a nice chunk of curly Padauk, about .65sg.  I made a guitar and a violin out of it. The guitar I really  like but I really don't like the finish on the violin at all. Sometimes you win, sometimes you lose. I used a pore filler and I just don't like it. On a sample it looked great. I used Osmo oil/wax finish on the guitar, and it looks sweet. That might look pretty good. Very resonant wood. Make the tops, and let them decide what back they want to go with.

I have a photo, but I don't know how to manipulate stuff on my Kindle!

[Ken_N]

I took a photo of the wood, then decided to just cut it up. An hour or so later, it just needs ribs sliced off the edge piece. The check isn't deep, but it is outside of the button. The wood isn't perfect, but it should sound really nice. A quarter teaspoon of HHG and a tsp of water is ready to shore that up before I glue the halves together.

The pre filter on the air cleaner is redder now.

 

 

[Ken_N]

Wow. I don't even remember doing all that in January! The basement is cold; it got as cold as 47, but now starts at about 50, and up to 54 degrees or so. Still too cold for MY comfort.

I'm doing 3 violins. I'm making ribs now, and have two on forms, and one on a skeleton form, like suggested by Andrew Carruthers. https://www.andrewcarruthers.com/skeleton/

I wanted to change it to use blocks that don't need to be trimmed on the back. This one has a 6.5 mm or so curve in it too. So the blocks are 3 mm low at the ends, and 3 mm high in the middle. 

My glue warmer died, so I'm dead in the water. I found some things out about forms.

I glue my blocks on with small chunks of wood on each end. That isn't bad, UNLESS you move them up and down 3 mm, and have another piece of 1/8" hardboard besides. 

I should use square pieces for gluing; then they will work for easy clamping.

I think I'll make a new skeleton mold out of 1/4" ply or something. Then the whole thing would be 1/2" thick. Good enough. I think I'll also make a full pattern out of the hardboard on both sides; cut in to mount the blocks. Then the ribs would be easy to bend without having to check both sides constantly. The cherry gets pretty stiff with the heat, but it is still easier to bend around something.

Make sure the pattern is on center of the form! 

It should be easy to tack to pieces of hardboard together, and cut the profile on. Drill bolt holes through at while they are together, and it should work really well.  A fine blade on the bandsaw should to that easy. A lot easier than cutting 1/2" whatever, and trying to get that smooth and square. Catnip (John K) has a spindle sander. It gets things a lot more square than a file and a flat scraper! 

Actually, I never had a bandsaw when I made my other forms. 

This one will work for this one; I only need to get the lower bouts on, and linings. When I get the ribs all done, and the outlines of the backs and bellies cut, I'll show what's going on.

[Ken_N]

Well, I have 2 of the ribcages done. The one still needs the linings tapered some. The other one I might give up on. I cut the back too small when I was roughing it out. Why I don't do the ribs first I don't know.

Would someone tell me to do the ribs first?

I have a high arch Montagnana of Sycamore and Englemann. He has a very stiff structure that is very thin. The back is fairly normal. 

 

The other one is based on Andres Preuss' New Concept Violin. I think of it as a cross-over between a violin and a guitar. This is the ribs. They have a 6.5mm or so arch built into them. I placed the end blocks 3mm high, and the corner blocks 3mm low. The back is carved with the 6.5 arch on the bottom. The long arch is about 15-16mm, so the middle cross arch is about 21mm or so. 

 

The belly will be bent lengthwise to the ribs, but also crosswise about 6mm as well. It is 4mm at the edges now, and 2mm or more in the middle. It is Port Orford Cedar, because I had a piece that was the right size and happened to be 4 mm thick.

You can see how the skeleton mold allows you to mark the inside of the linings on the plate, besides just the outside of the ribs. I used a Dremel to cut the center out. I haven't marked it out to the form yet. I won't do that until it is bent, and the struts, crossbars are glued in. I don't know how much it will shrink!

I have a board to build the ribs on using the skeleton form. I cut the 6.5mm arch in it on the back side, and it worked well to get the ribcage arched correctly. Now I will carve the shape of the belly into it. It will be like a solera for building a guitar.  The bracing will be something like what I laid out here. The top diagonal might go further, but die out before the sound post. I seems like the sound post area needs to be somewhat flexible. But I have no idea what that will be yet!

Now I  still have a lot of work to do.

Questions, or thoughts?

 

[Ken_N]

The bent one got easier for now. It split in half flexing it into the form. Spruce might work better. Maybe half carved, and half bent? The cross arch is the problem. So now I just have the Montagnana and the baroque guitar in A started. 

My life got easier. Cool! I like easier.

[Andreas Preuss]

 

i bent the back as well to the concave rib garland. It depends of course on the flexibility of the back plate. On a second thought this might actually be a very precise method in calibrating the stiffness of the back. You could push it down to the rib surface with always the same weight. If the weight can’t close the plate on the ribs it’s too stiff and more material must be removed.

——

On the top I don’t quite understand how you bend it lengthwise on the convex longitudinal rib arch AND at the same time crosswise. (?) To me you can do either one but not both. 
 

————-

Do I see correctly on the photo of the top that it has a doubled edge all around? I do the same.  I just bend the top plate from a 2mm thick board with soaking and heat.

The last picture shows the bracing for the top plate, right?

i don’t know what’s the idea behind it, but for those things there is probably only trial and error. Setting a diagonal bracing is certainly interesting. Does it replace the bass bar? 
 

I was thinking of curved bracings similar to the nodal lines of the ring mode of the chladni patterns. My idea is that especially very thin top plates need cross grain stability support.

Looking forward to see the further progress.

[Andreas Preuss]

16 hours ago, Ken_N said:

Maybe half carved, and half bent?

For bending a top plate, uninterrupted grain seems to me the optimal solution. So no carving at all. A 3mm thick plate bends like butter and has enough margin in the thickness for small corrections. I think 4 mm is still possible, but that needs to be tested.

[Ken_N]

Yeah, I was trying to bend it both ways! Lengthwise is simple. Crosswise must have been too much. It seemed like it was almost there. Maybe a flat plate first, and then glue on the doubling. I hadn't thought of that. This was 2 mm thick. With the doubling it weighed about 60g. It seems to me that the POcedar was on the high side of dense. .48 or so. It was pretty flexible, but the 3-3.5 mm edge kept it from being floppy. It pushed in fairly easily almost to the bottom of the form; so about 6-6.5 mm curve both ways. The long arch ends up looking like 15.5 mm or so.  Just a flat piece, and then doubling might work.

This is the form, and the diagonal bass bar:

 

The diagonals hold the long arch in place. But I can't have the one going into sound post. so to add some cross grain, I thought the horizontal brace would work. It is much smaller than even most baroque guitars, and it doesn't have a sound hole being squished by 60 pounds of string pressure. And the bending should add a lot of strength. 

[Ken_N]

Starting to bring the Montagnana belly down close to finish. Roughing it didn't seem unusual; just spruce. It is Engelmann, but I think it was .46 or higher sg. I don't remember, I roughed some of it out a couple years ago. I have it getting close to thickness; from the outside, the inside is pretty much done. The measurements on the poster are very thin. 1.5-2.5 for most of it. 3mm in a band in the middle. The middle is 3-3.5 now, and most of the bouts are around 2.6 mm.  

The spruce is stiff. It has grain that seems to go all over. Not matter what way you approach it, it might not like it. I think it was from Idaho. That said. I think it is pretty good wood. It will just be a bear to finish it up nice. I'll have to use the magnifier for sure. It looks FAR worse in photos than it does to my eyes! 

If it is all smooth, it should look very cool.

It is still a little thick in some spots, and the edges I think I'll do after gluing everything up. It started yesterday at 85 grams, and now it is 70, so almost 20 percent drop; mostly on the edge and recurve. It went from A 440 and G 98 to  G 392  and F 87   That's just using my guitar.  Apparently, the outside doesn't affect the mode 5 and mode1 or is it mode 2? 

I'll work on it some more now; probably more in the middle areas to bring them in. It is easier to see what they need when the edges and recurve are in. Then I can tackle cutting the f holes out, and trying to make it pretty.

That might take a while.

 

Ahh. I checked it on Audacity, and my guitar must be flat, and I hear a low note that isn't there. I have peaks at 155, 264 and 379

[Ken_N]

The last couple of afternoons I've sharpened all my edge tools, and then polished them. I bought two double sided water stones to place some old stones I had about a year ago. I went through all 4 grits, and then remembered that I had some lapping paper from Woodcraft. I think it is 5,1, and .3 mil film. I hadn't used it. 

I went through the 'grits' with that, and the edges gleam! They should work better. Some even needed the pedestal grinder first. I didn't know that they were that bad.

Sharpened the tools cut nice. I still have to watch the belly because the grain shifts direction every 3-4 inches.

I worked on the belly some more, and it STILL does not move at all if clamped down, and pressed in the middle. I had a dial indicator on it. It doesn't move at all. 63 grams.

I'm guessing the long arch is still too stiff?

I know it will loosen up when I cut the f holes, but will it be enough? The edges all the way around are NOT stiff by any stretch of the imagination. Far from it.

I could cut the f holes in, and see what happens. It would be nice to get it to move SOME first. The center of the lower bout is the biggest target.

[Ken_N]

Well, the other day I found a piece to replace the experimental belly; a 1/2" thick piece of Sitka. I sliced it into 3 pieces, and planed them to 2mm or so. I bent the two halves to the 7-8 mm arch, and then bent them 8 mm more as best I could. Then I joined them fitting them on the carved form. It isn't perfect. I decided to glue them with bands like they put on backs of guitars. I could glue those on the same time I glued the bracing. 

 

I added the little brace under the sound post last night, it seemed a bit to floppy there. The 3rd piece was used for doubling the edge. It is stiffer than the Montagnana flexing by twisting, but when pushing down on the bridge area when it is clamped to the ribs it is more flexible.  

I check the tap tones, and it sounds like a violin. 166 low, and a bunch from 324 345 375 398 418 427 554 643. The ring mode is somewhere in there.  It should at least make noise. It is 67 grams.

The long arching on the top looks like a 16mm arch or so. The cross arching is like an 8mm arch with no recurve. 

 

 

The cherry back looks like a 23mm arch or so. It needs a lot of work still, but the outside was roughed to see if it looked ok. These are the ribs:

 

The Montagnana needs the neck finished and set, so I can start on the finish. 

 

I have another experimental instrument. An all acoustic Les Paul. Basically a 13" arch top. The upper pickup is the sound hole. I won't add the lower one, or the switch and dials. It will be thicker, 2 1/2" ribs, but it does needs some internal volume.  It may need more tone hole volume, but I don't know yet. The belly is further along than the back.

Yes, it is Home Depot cedar decking. But the center is perfectly quartered.

 

[Ken_N]

I have color on the Montagnana violin. I was trying for red over gold. It doesn't look terrible. Shellac and resin, with clear varnish over that, for the golden base. Then red. Real red, Kremer Ruby DPP TR. with some green oil paint in it. Then after working some red off; it wasn't applied everywhere, a coat of varnish with green oil paint in it. The second varnish was red, the third more like green brown. 

It started shrinking down after a week of being in the sun, and in the trash can. It seems hard now, but I'll let it set a while before finishing it up. A baroque set up. I works with the very high arch. 

[Ken_N]

The arch top is coming along.

 

[Ken_N]

Well. The cello has varnish on it. I decided to varnish the parts individually. It worked pretty good, but I did have a setback. Scraping the sides for a ground coat, I had it on a saw horse; instead of the support beams I made for the cello form AFTER THE INCIDENT; and it fell off; cracking the upper and lower bout on the bass side.

I got replacement rib stock from Old World Tonewood, and then a bending iron from Luthiers Workbench, (I bent the first ones using David Burgess's iron) and it seems that the already finished back and belly will still fit just right. The ribs are tapered, so I wondered about that. But they do fit snug on the form, so that helps.

Kremer Ruby DPP TR pigment. 

The little 13" archtop needed a couple coats of clear varnish where the bridge will go. It is just shellac and other resins, and very corduroy red cedar. The varnish will hopefully keep the bridge from sinking in. The rest of the belly will have a couple coats of Oslo clear, just for feel, and upkeep.

When it is good and dry; and doesn't smell; I'll glue the back on, then pull out the form piece by piece; and glue the belly on. Then it is fingerboard, and fittings/setup. I'm thinking of a piece of Osage Orange for the board. Acidic acid to darken, and black Osmo as a finish. 

It really doesn't look THAT red in person.

 

 

[Ken_N]

Well I need to make a fingerboard. I have everything else done. I added another thin coat of red on the belly. It was a nice orange/brown, that didn't match the back and sides much. Yeah. The photos don't say so, but that is what I see. 

There is FAR more difference in color, and it doesn't look like paint in person. It is surprisingly light; about 5 pounds. The form I made for it with 3 layers is 15 pounds! 

The fingerboard will be Osage Orange. It is .85 sg and seems to take acidic acid stain (vinegar steel wool) pretty well. A coat of black Osmo oil should make it look and feel nice.

 

 

 

[Ken_N]

I went out the other day, and got some fingerboard wood. I found a piece of Surinam Ironwood, I'll use it for the Cello. It is the heaviest wood I've ever found. 1.33sg.  It should be a slow wearing fingerboard! The belly is ready to start buffing and polishing to get a gleam, and not a shine.

[Ken_N]

I've been working to get this cello finished. Setups are a rare thing for me, so I'm not good at them! I have a bass bar sort of in place. It doesn't fit perfect, but I need to put a new one in anyway, because the setter went in too many times; and it almost has a chunk out of it. Should be goo enough to get the bridge set up.

The fingerboard was pretty easy to do. It is probably still a little thick. But that is what planes and scrapers are for.

The bridge is fit to the body, and trimmed down some. I should be way high. Bridges are not a problem. I'm almost done on the neck side. I do get carried away, but it is fun.

Pegs. I usually make them. I don't have a fixture made up for cello pegs. If I do another I'll make one, and make my own. These are plain Jane. They were 14mm at the knob end, so they seemed too big.  A 12mm hole seems about right at the pegbox. So I needed a peg shaper. I made one out of a piece of cherry. Something harder would be better; but it worked.

I made it yesterday, and it started to split on one side. It already had a check, but at first I wasn't thinking that I needed 2 separate shapers to cut the pegs. I glued it up overnight, and started on this in the afternoon today. It doesn't work great; but it works. Certainly a lot cheaper than $150 or so. I filed the top part, and put it in the lathe to smooth that part up. 

Making a peg is easier that playing around with the shaper. It is certainly a lot more fun. 

I started the nut. I used an offset from the Ironwood. I bought blanks for the nut and saddle, when I bought some other stuff; something I never do: but the nut was about 2mm too narrow. I didn't have the dimension police around to tell me that a nut can only be 50mm wide!

 

 

[Ken_N]

I put a new sound post in. It is longer, and maybe closer to the right spot. I lowered the top of the bridge, and cut the radius to the top edge more. It is around 2.5mm or less. I finished rounding out the legs, and did some on the flat side. The wolf on the D isn't as bad, or is gone. The D# on the A string is still there. It sounds like;; TWANG! Cool. 

 

 

The scroll is easier to do on a cello. At least it seems to be. I can see bigger things better. You can see where the nut split on what must be a check. It is my take on Matt Noykos nut carve idea. 

 

 

 

 

 

The top is bigger than the back. 750/330/220/420 and 130/320/210/410 

 

 

 

[Ken_N]

Cleaning up yesterday I found the photo from the calendar that I made the cello from. 3 X 5". It was aChristophe Landon Rare Violins calendar. I made a viola from the mix between the two. I haven't made the violin.

 

[Ken_N]

I watched a video series by the Swedish maker Peter Westerlund about the way he makes instruments: by tapping and scratching. 

I had to try in; and it works! 

Well I don't have a finished instrument yet, and I messed the back up by not watching what I was doing when cutting the inside by the corners too thin; but it works.

Peter even mentions that if you get a thickness around 1mm you've done something wrong. Probably sometime early on, he fount that out!

The belly has a LOT of profiling on the outside, so you have to leave the entire area thick when starting on the inside. Now that it is about ready for the bass bar, I see that the inside arching is almost exactly as I do for bellies starting from the inside! I just kept the area around the soundest thicker; over 3.5mm on this, it is only cedar. 

My plan for bellies is to draw lines marking the inside of the arch at the inside edge of the upper and lower blocks. I draw lines from the center of the blocks through the upper f hole (on the plan) from both blocks. This gives the terminal point of the cross arches. So the placing of the f holes determines the arching to some extent.

This viola started as an experiment. Someone on maestronet said that he makes small violas of cedar and mahogany. So I had a small piece of each, and make billets a few years ago? So I decided to try Peter's method. 

The belly IS very flat, The back IS a complete curve. That part works. You CAN get the thickness by matching the sound of the inside to the sound of the outside. I HAVe been using something similar in area tuning, but didn't tune the entire plate, and didn't try to match the inside. It isn't free plate tapping and scratching. The plate has to be dampened. 

Tuning gets very precise when you get closer. I found that I needed 400 sandpaper to tune high spots when I couldn't see, or feel a high spot. 

Working on it yesterday it went from 79 grams to 78 grams, doing a lot of work, especially on the ends of the diagonal arches that I noticed were too high. I checked, and the sounded high too. At 78 grams I got another set of tap tones holding it in a spot less than an inch apart. I wasn't looking for tap tones, but it was interesting that the tones were B (second string on a guitar) or so, and the octave below. There was also note in between at E.

Then it opened up, and the other pair of notes came out almost an octave higher at A, with a low note when tapping near the edge around G#. 

I did an analysis on Audacity, and that is what I get holding in the 2 places and tapping near the middle and edge of the lower bout. 

The sound opened up just feeing the ends of the diagonal arches some.

The viola is a 390mm viola drawn from the Storioni in the Makers of Cremona book I borrowed from the MVA library a few years ago.

Now I need to buy a mahogany board to replace the ruined one.

I just thought of something. If the diagonal arches seem so important. If they are about 25 mm apart at the bridge, would it be just as important that the inside edge of the bridge foot overlap it by a mm as the outside edge overlaps the bass bar by a mm? 

23-46mm, or 11.5mm long feet. 

 

 

 

 

[Ken_N]

I went to Woodcraft yesterday, and picked up a little Japanese keyhole saw. For $9 it was a no-brainer. Besides, I needed a board of mahogany. I found that too.

I put the bass bar in the day before, so I trimmed it down. Bassbars used to be more troublesome. This one was easy. So I tapped it on Audacity, and the high A peak is gone, but the lower peaks are about the same. The highs evened out more.

I haven't ever used tap tones for anything. They are just interesting, and seem to show something about the character of the sound that you might expect. Also when I do the larger Guadagnini viola, I can see what difference a larger size, and Sitka instead of Cedar does.

It was at 76 grams, now it is 80.

 

[Ken_N]

Last night I got ready to glue the viola together. I had to change from cello carriage bolts to the violin/viola ones. I have another set for guitar. I'll only use 24 of the 36 clamps.

I set my neck when it is still on the form. I've never even considered doing it any other way. It just seems like a bad idea. 

I'm doing this viola to test out the method of Peter Westerlund. So far the arching ideas work, and the ended up almost exactly as I do them from the inside out. There are a lot more high peaks in the resonances of the free plates though. 

I know that Peter doesn't check for that, but I wanted to see what they actually were.

I will keep everything warm today, and glue in the afternoon when I start working. 

Knock it off the form, glue the back, glue the neck, and maybe later, or tomorrow glue the belly. I might do it on the dining room table. It's only 50 in the basement this morning.