New Blog, Kensarchtop

I'm putting the Archtop build on a new blog: kensarchtop.blogspot.com

It should be in depth, and deal with more than just building. I plan on getting into design, inside first, string tension on the body, and whatever else comes up.

See you there.

Ken

Wood for the Archtop belly

UPS delivered my wood for the Archtop belly yesterday. Curly Redwood. It felt very light. I mean it felt really light. I measured it, and weighed it. My senses were right, the wood is .36 SG. That's pretty light by any measure. Cool.



I trimmed the width off to 8 1/2" and then took the piece left over, and turned it into 2 braces. The cut was out of square some. I was hoping for that. It measured 1 5/8" thick, and I wanted to have about an inch in the middle to work with. So the first step was to cut it parallel to the grain. Then I planed the surface, and cut again, aiming for 9 mm width. The one is 9, the other is 8-10. Oh well. I noticed that the even one is a fourth higher in tap tone than the other. I'll put it on the treble side.



The wood is very lustrous when planed, and the quartered ends are very silky. It should look good when done.



I carefully marked out the splitting cut, even marking a 3mm kerf on every surface. I found a foolproof, (I think) way to cut thick pieces of wood out. I used to clamp them, and saw down from the end, but now I just do that to get the saw orientation right, and then I put it in the vise, flat on the bench, and saw it that way. I cut some on one side of the bench, and then go on the other side and work on that side of the line. I forgot to take a picture of that.



Let's say you go 1" on one side, then you go on the other side and saw until it is even and then go 1" more on that side. It works good. Maybe 15 minutes to cut out a 23 X 8 1/2" piece. I used my 11" ryoba saw that has 3 teeth every 2cm on the rip side. The cut wood, and chips smell like the Paperwhites that are flowering on the dining room table. Somewhat similar to Port Orford Cedar.



I found that one side taps about a third or so higher than the other. They are cut very evenly. 1" in the middle, and 1/2" on the edge; so it isn't a size thing. I might as well make the high side the treble side. So I guess that they will be glued up just like I have them pictured here. I'll make a cutout, and see where it might look the best vertically. It's about 3" long, so there is some choice there.

An Archtop?

I haven't posted on this blog in a long time. But I have things finishing up, and a new project.

I have a lot of things going on. I have a violin that is determined to not want varnish on it. I will strip it for the second time, and bring it under submission. I have a Gofriller violin that seems like it will be my best so far. It is almost ready for varnish. I think that I will varnish them together.




The newest idea is to make an Archtop guitar for myself. I saw an outstanding one on a site of an excellent maker in Chicago. He calls it his Amati. Cool. Yes it is:

http://koentoppguitars.com/blog/the-hog-amati/

I have a big slab of European sycamore that I bought for a cello back. It is big enough to get an Archtop out of the top half. The top is maybe 16.5" where the widest part of the lower bout would be, made a little wider, but the bark is there on one side cutting the width down. I'll probably do it bark side down, so I drew it out about 16" wide. That will have to do.



There's nothing quite like using a camera with no flash on gloomy days inside the house.

I have a piece of old curly redwood coming from Orcas Island Tonewood. It looks cool. I should be able to cut a couple of bass bars, well, diagonal (they call them parallel?) braces out of it, and get the height out of it by careful sawing on an angle. The "Hog" has X bracing, but I am going to carve it from the inside with X arches, so the stiffness there will be built in. I hope. The so call parallel braces are supposed to make a crisp, clear sound. A sound clip of one of Dan's Chicagoans being played that has parallel bracing sounds almost harp-like. I would call that crisp and clear.



http://koentoppguitars.com/blog/shop-concert-with-nate-wilkinson/


I have a cool piece of curly Bubinga for a fingerboard. I'm thinking of playing on the darkness of that; and the fact that I don't have a piece of wood big enough for a solid neck; to make a laminate neck. The outsides will be from the top half of a Birdseye piece I have. It was discounted because a third of the top is funky. But I should be able to cut out 2 neck sides, and a faceplate out of it. I should have, or be able to find some dark wood to use for the middle.



The tag on the wood says 06/15/11. It should be stable by now!

I just finished making a convex bottom hogging plane made around the Lie Nielsen Scub plane blade. It worked well on a test piece, we'll have to see what it does on the real stuff. It looks good though.



Everything should be pretty straightforward except:

Truss rods. It's a new animal for me. I'm thinking that I will use a 14.5" 'hot rod' double action truss rod. Adjustment under the nut. That should put the other end just before where the fingerboard extension will be dovetailed in.

That brings up the only other part I can think of now that is a puzzle(I'm sure more will come up). It seems like the fingerboard extension gets glued right on to the upper block besides into the neck. Is that the case? It seems like that would transmit a tremendous amount of sound that way.

I looked into scale length and string tension. It seems that .001 up in string diameter makes 3 times or more difference in tension than .5" of scale length does. When you read about it, people seem to think that scale makes such a difference. If it does, I don't think that it is from tension. Maybe the D'Addario formula I was using was printed wrong. I have that each .25" of scale changed the tension 1%, but .001" of string diameter changed it 8%. I haven't settled on that yet. 27" baritone? Now that would be different.

Michigan Violinmakers Association

I went to the Michigan Violinmakers Association meeting on Sunday. It was pretty cool. I brought a few instruments to see if they thought I should still be there. They didn't throw me out. But no one wanted to play them either. Look at them, and see how many places I messed up. But they didn't scream PLAY ME apparently. A lot of good feedback though, especially from one soft spoken guy who works in Ann Arbor. Sorry, I'm terrible with names, but I think he was David Brownell. Peter, the president of the club seemed to be the most enthusiastic about the instruments. Apparently, he can see past the flaws and see the vision. That's my interpretation, and I'm sticking with it.

There were three new members there. Paul Chen, I think that's right, has a lot of experience, and worked at Oberlin for one of their workshops with Holmes, and Burgess. Brings a lot to the table. Then there was another, from south of Chicago, Jay Damm. That name must have been fun in school. He is a shop owner, and I imagine has had his hand in every aspect of the business. Both are fairly young guys. Everyone looks young to me!

There were maybe a dozen there. Many were in restoration. Some were shop owners, including Matt Noykos, who gave the main presentation on preparing a fingerboard. It was very well done. He uses some stuff; magic in a tube, for getting just the right balance of dull and shine on the finished board. Ebony polish from Old Wood. http://www.metmusic.com/varnish/old-wood-varnish/extra-products/27681/old-wood-ebony-polish-20cc/ Some there said that the Old Wood ground system is good. But then they always add, pricey. Yeah, but is it worth it? Does it do more than anything else you've tried. Would you use it again? If you would, is it only the price holding you back? Those are the questions I wanted to ask.

I always have questions. Some I didn't get to:

Does your wood move all over the place when you rough it out? I don't mean on the bench, I mean as far as flatness. I've decided to rough it out somewhat inside and out. Flatten the bottom and join it square, and THEN glue the halves together. Maybe then they would move as much taking the final 2 mm a side off of them.

The secretary is Gregory Young, who just was hired as a Ferrari mechanic. Really? Is it more fun changing the double clutch pads on an F40, than swapping out the disc on the clutch on a 2009 Ford Fiesta? DAH! That is a no-brainer.

The meeting was a lot of fun, and very informative. I found out I want to make more violas. For many reasons. The first, and foremost is the way they sound! I didn't know that they sound SO MUCH BETTER than violins. Yes they do. Rich and sonorous. Matt did a final soundpost adjustment on a viola that he fixed some cracks on. The player was there to pick it up. She explained what she liked, and didn't like; he adjusted it 3 times, and it sounded great.

Another reason I want to make more, is that they seem to be like the only venue for someone like me who doesn't understand conformity. Violinists are very, very picky, and want everything exactly the same. Michael Darnton assured me that they don't generally measure every dimension, and just want it to feel right; but that's not the way it seems. Violists on the other hand will put up with all sorts of things, if it gives the sound that they are looking for.

There are big ones, small ones, and gigantic ones. Long strings, short strings, and gut strings, and steel strings, and all that sort of thing. High arches, higher arches, arches right to the edge. Get the fingerboard in a 2:3 relationship to the stop, and it all works out.

Did I mention that they sound WAY BETTER than violins?

Loose Ends

I have a LOT of loose ends. I need to finish up 5 instruments. Let's lay them out:



The first two are for the grandsons. This will show you how my brain works. I saw this 10 string baroque guitar by Stradivarius.



Cool thing and it sounds great. Checked out the size, and they are all over the place, but basically a smallish body with a long scale length because the saddle is set very low. Then I got the idea I could make it smaller for the boys. Easy enough, right? Then I saw a ukulele at a garage sale for $2. It had a case. The case looked to be the right size. I bought it. The Strad body fit right in.

The ukulele is a baritone, didn't even know that there was such a thing. It is tuned the same as the bottom four strings on a guitar. Cool, the boys could have fun with that, and the notes would be the same. AGH! The ribs on one side are cracked from the neck to the bottom block.

More work. The neck proved to be loose too, Was never fitted well. The ribs are fixed, the neck fits now. New varnish on the sides.

I need a new rib iron. Tried to bend some rosewood for banding the guitar, and the heat gun broke.

So I need a rib iron, need to glue on the ukulele neck, and buy another peg. That one is easy.

I need to bend and glue the banding, glue on the neck, put in frets, and glue on the bridge, and varnish the little guitar.

Now for the violins:



The Gagliano viola needs a tailpiece, nut and saddle, and a bridge. Easiest one to finish.

The Gofriller viola, and the del Gesu violin both need finishing up on the woodwork before varnishing. I wanted to string them up and see (hear) any differences as I thinned in the recurve area. Those aren't really hard things either. But they do need to get done before I can start on other cool stuff.



Cool stuff? Oh yeah, there is always cool stuff to do. How about Walnut, and Quilted Maple Gofriller violins? Gofriller's because they look cool, and the lower bout is only 199, and the wood is on the narrow side. Still need to draw the plan up. Do them together so any sound differences can be played around with.

I have another hunk of Birdseye, one Cherry piece, a piece of Sycamore for a 5 string. Oh yeah! There is still the 5 string Cherry and Poplar 5 string in the drawer that I have to fix the purfling on. I must have been in a fog when I did that job. Where do I hire these people?

I only have three boxes to keep the instruments together with all their stuff. I need at least 2 more. I have three other ones, but they house exotic wood for fittings and fingerboards, block wood and clamp wood, and wood for linings and ribs. Maybe I could use the big blue box for that stuff...

Guadagnini Viola?

I haven't added anything here for a while now. The other day I got my copy of The Strad, the last one unless I change my mind, and there was an insert from Bishop Instruments. I like looking through them. The Vuillaume looks great!

The f holes look really cool, and seem even larger than del Gesu's do. The upper corners seem a little too long, but it is a winner. The Sgarbi viola catches my eye too. Wanna talk "barrel shaped"?

Then there is a Guadagnini viola. Huh? That doesn't look like the poster I have. That one is absolutely frumpy looking. This one is earlier from his Milan period; back when he made them cool looking. His later ones do nothing for me. I think he started listening to everyone telling him what he had to do, instead of just doing what he did.

I took a piece of paper and held the pamphlet up to the window, and drew the outline of the purfling, and the f hole in ink on the paper. Then in pencil I drew it up, recreating the lines. I came up with all kinds of connecting points, but it was just a sketch, and many times they don't materialize in a real drawing.

Convinced that it will work I get a 11" X 17" piece of stiff paper, and start drawing. I wondered if they have a full shot of this thing? I googled it, and was shocked! It was butchered!

Well, maybe butchered is a harsh word, but it is close to what I was thinking. The text on the site says that it was made shorter at one time. Why? Want a shorter instrument? Make one. Ah, then it was made longer? I bet it was the name that drover their frenzy. "Short violas are in, let's make this puppy shorter. Then we can make a killing on it." "Guad's are all the rage. Let's tweak this one a little, and say it was re-constructed. Then we can make a killing on it." Yeah, I'm a cynical guy.

This is what I have so far:

I will go with the original f hole I drew. It gives about a 360 mm string length. Maybe on the short side, but it should make it more comfortable to play. The longer one puts the lower hole in a more conventional place, but this isn't about convention.
We'll see what develops. I may lower the upper hole some. It is higher than the original, but all the lines converge on it. The eyes are still 51 mm apart.

Roughing the re-curve

The central part of the cross arches can be accurately defined by the catenary arch on the inside. How close you make it to the edge will determine how close you come to a curate cycloid as your outside shape. The recurve starts out by figuring out where the line of inflection, and the low point is going to be. The low point is easy; look at the plans; or in my case where I'm making it up from scratch; come up with a number. I'm using 7 mm in the c bouts, and 9 or so for the rest. I'm putting double purling in; since I'm making it somewhat like a Maggini shape, so those numbers should work. Amati models may go in further than that, an other models may get closer to the edge. Now we have to find the inflection line, where the concave curve changes to convex. Turns out it is easy.

You know how a cycloid is formed. A disc is cut out with a circumference that will cover the distance form low point to low point in one revolution. A hole is placed 1/2 the height of the actual outside arch (height of the arch minus the thickness at the low point), a pencil is inserted, and the disc is rolled on the circumference. We don't need to make all that, we just use some simple trigonometry. Figure out how far the disc rolls in 15 degrees, find the sine and cosine of 15 degrees, and use those numbers to find where the pencil would mark at 15 degrees. Do it for 30, 45, 60 and 75 degrees, and you will have 4 points that define the recurve exactly.

I had to edit this part. I was trying to find the point of inflection, and forgot to add the width it rolled with the disc. DAH! So I did it over. For a normal Strad type arch it is about 66 degrees of rotation at the c bouts. For a slightly wider and shorter del Gesu arch, it is about 72 degrees of rotation. So, a Strad arch is about 75% convex, and a del Gesu about 70% convex. The upper and lower bouts will have even more rotation to get to the point of inflection. I draw out some of them, I picked 7 on this one, and I can pick and choose what sort of tool I will use to cut them. Here are my choices for concave curves:

And the recurves and the ones that will cut them:

Turns out, the recurve, even in the c bouts of this 5 string, use my three widest tools. The bottom of the lower bout even needs to be somewhat flatter. This is what I came up with doing one side of the belly and the back.

These are not finished. This is only to rough out the recurve for preliminary tuning. I also only cut the recurve part first, and didn't blend the central part of the arch in to it. I cut the recurve from the low point to the inflection line, or a little past it, and then use the thickness punch to put pin pricks on the inside to finalize the inside arch. It is only after that that I use the punch to do the outside.

This is what the inside looks like:

Well, those photos don't want to load. I'll put them in another time.

You have to be aware of how much the concave arch goes down from where the platform that you have is set. This one goes down just less than a millimeter in the c bout area, and less than 1/2 of that everywhere else. This means that for this one, I will end up having to cut the central area, without being able to use a full arch like I roughed it out with. What the maker does when this happens is up to individual style. They can just keep the thicknesses really thick, or cut them out with smaller cutters. They can make a hump, or a tiny radius, or any number of things.

This may explain, or confuse!