To regraduate or not...

[Mike Mandelas]

Beeing privileged to have some of the best luthiers worlwide in our forum i'd like to ask them their opinion (for one more time). I have a Romanian fully carved bass with low piz volume and a better arco sound. Taking the magnetic caliper (which measures the thickness from the outside) i found that the top is rather thick, with more than 9 mm in the center and more than 7 mm around the f holes. I have the Wake's plans and also Amati and Panoromo plans and all of them show proper graduation schemes, more al less like the violin's pattern, with less thickness everywhere. The bass has nice tonewoods, with an excellent flamed back and a very good medium grained top. The bass came to me as a gift from one of my students who makes a astonishing carrer in engineering in Romania. I have a lot of experience in regraduating violins but in basses it is going to be my first venture. I have all the necessary tools (finger planes, scrapers, calipers etc) and i have experience in opening the top and replacing it. Do you think that regraduating it i can improve the quality of the bass? I need a louder piz sound, seeking for a "booming" response. What other factors do i have to take into account?
Thanks in advance
Mike

[Ken Smith]

First off, the plans you have are more than likely false. There are no known confirmed Amati Basses period. Several claim to be but none that are agreed upon. So, what ever graduations you have there for Amati is some old bass that is claimed to be and not something that any Amati developed.
On the Panormo, most of his basses I believe are 6mm throughout. No graduations to speak of. Also, the wood is quite hard and dense on the top as compared to softer Pine or Spruce.

That being said, the density of the wood itself will govern how thick or thin it can be. The width, length and arching, mainly the arching will also have an effect on the Top strength or lack of if flatter.

Each bass must be individually evaluated for graduation and not according to some plans of a bass whether the model is true or not.

Another thing to consider is that many of these old basses that have been recently measured or mapped out have either been altered in size or thickness or both. Also, the bass may have lived for a century or two as a 3-string and then converted to 4-string in the last 100 years. That 'life experience' of the bass has something to do with the success or failure of its graduations as well.

Let's put it this way. If graduations were an exact science then all basses made today would sound perfect. The one you have is proof enough that no such science exists. Wood itself is imperfect. Therefor no science in the world can standardize the making of wood products.

Here's a tip for you. If you tweak the thicknesses in the Top, work 'around' that Bassbar and leave a small platform build up of wood around it like a shelf. My Gilkes was made this way and also a full sized bass attr. to Maggini was as well. I was told by one of the former owners of the attr. Maggini that a repair man about 50 years ago or so thought this was wrong and removed the bassbar, re-graduated that platform and re-installed a new bar. The Top sunk in shortly after. Apparently, the old maker was smarter than the repairman but could only roll over in his grave watching his bass get raped centuries later.

Once the wood is removed, it is gone for good. Re-adding breast patches is the closest thing to fixing what was done in error.

Will re-graduating your particular bass get you what you want? Well, maybe what the bass does now is all the wood can do. Then again, maybe not. A thinned top will be more responsive for a time but will be weaker as well in the long run.

I usually tell people that if the Bass doesn't do what they need it to do, get a different bass! In your case, getting it as a gift and the bass being or relative low value in the market, you have little to loose in trying.

[Mike Mandelas]

Indeed, the low value and the minimal expence drove me to regraduation. I consider it an exercise in learning the craft. I believe it will be a worthy experiment, even if the final outcome will be mediocre. Needless to say that your opinions matter a lot for me because i have no local point of reference.
Mike

[Ken Smith]

Indeed, the low value and the minimal expence drove me to regraduation. I consider it an exercise in learning the craft. I believe it will be a worthy experiment, even if the final outcome will be mediocre. Needless to say that your opinions matter a lot for me because i have no local point of reference.
Mike

Yes, I agree that under the circumstances and with your abilities that this is a good thing to try. My point was mainly that there are no 'exacts' with this method. Like with Violin making (I assume), the maker carves each piece of wood until IT sounds right and not matching exactly the Violins previously made as the wood varies even within the same plank top to bottom, front to back.

I have never done this myself but have been involved in the planning of many restorations that included graduations on my own basses. Most of which I played before and after repairs. Some were not playable before but the same rules of instrument health were applied. Usually wood is taken away but sometimes, wood must be added back in or a little of both depending..

[Arnold Schnitzer]

I agree with Ken on everything he said above, except that I don't like the idea of leaving the bass bar intact. I think the bass bar sitting on a hump can deter the vibrations you want to hear (bottom). Fitting a new bass bar is hard work, but worth it. You will also then have the option of siting it where it will do the most good.

[Ken Smith]

I agree with Ken on everything he said above, except that I don't like the idea of leaving the bass bar intact. I think the bass bar sitting on a hump can deter the vibrations you want to hear (bottom). Fitting a new bass bar is hard work, but worth it. You will also then have the option of siting it where it will do the most good.

Well, that being the case, how would you explain the Top sinking on that so called Maggini when it was re-worked to look more normal rather than left original as the maker intended?

I think I know the answer to that BUT, since you have a slightly different opinion of this 'platform' theory, I will let 'Maestro Schnitzer' respond with his rebuttal.

Maybe on this Romanian project it would be more cost effective NOT to Spring for a new 'Bar.. PUN intended..:D.. Arnold? You're up..;)

[Arnold Schnitzer]

You gave it away, Mr. Smith. If one thins the top plate, then springs the bass bar, there lies a recipe for disaster. Then to compound the problem, if one sets the neck in such a way as to require a bridge nearing 8" (21cm) high, the future is certain. That top plate is toast!

Any situation alluded to herein is purely fictional. ;)

[Matthew Tucker]

Here's a tip for you. If you tweak the thicknesses in the Top, work 'around' that Bassbar and leave a small platform build up of wood around it like a shelf. My Gilkes was made this way and also a full sized bass attr. to Maggini was as well. :confused:

the density of the wood itself will govern how thick or thin it can be. The width, length and arching, mainly the arching will also have an effect on the Top strength or lack of if flatter. Each bass must be individually evaluated for graduation and not according to some plans of a bass whether the model is true or not. :)

For the very reasons that Ken gives ... that every bass is different, and every piece of wood is different ... I DON'T think you should take Ken's tip

Its been discussed before, but the "shelf" on the co-called "Maggini" and the Gilkes seems to me more likely to be the result of graduation with bass bar in place. It hardly seems like a recommended thing to strive for just because it worked in those basses. or not.

Also, you should know that the graduations given on ALL Chandler's plans* are, according to him, taken from the one Busan model he copied while it was open at Heinls. I don't think he had the others open to measure. I don't really like his thicknesses, though they will work. But every piece of wood is different.

You have only given two measurements but the thicknesses sound, to me, pretty normal. 9mm in the centre isn't that thick. Have you made a map of the top with your gauge, at all points on the top? Probably most critical are the thicknesses near the edges, but as Ken said, the arching shape is important too. How would you describe that?

I think most luthiers would agree (do you?) that there are probably other things you should try first, like strings/soundpost/tailpiece/tailgut/bridge etc, that aren't so drastic as regraduation. Have you been down that path yet?

And how about posting some photos of the patient, and/or your graduation maps, in case anything stands out? Its a bit hard to say anything without seeing the bass.

Matthew

* including the plans of the "Amati" model, that everone now knows is probably not an Amati, any more than Ken's "Loveri" bows are Loveris! But it says "Amati" on the plans because Corky Davis had some documentation (right or wrong) and told Chandler thats what it was, so that's what he wrote. What else could he have called it? So those plans will continue to be called the "Amati" plans for as long as the plans are sold!

[Ken Smith]

:confused::)
For the very reasons that Ken gives ... that every bass is different, and every piece of wood is different ... I DON'T think you should take Ken's tip

Its been discussed before, but the "shelf" on the co-called "Maggini" and the Gilkes seems to me more likely to be the result of graduation with bass bar in place. It hardly seems like a recommended thing to strive for just because it worked in those basses. or not.

The highlighted comment above in the partial quote is an incorrect assumption by Matt.

Matt, the Gilkes Top was original as mentioned. There was a slight raised area under the Sound Post as well. As far as the Attr. Maggini, the former owner at the time expressed how the recent repair had altered it from original.

That Bass I have actually played and the Gilkes I have owned for 5 years and know it inside and out. If you have questions about the 'Bar platform being original, ask Arnold. He worked on the Bass and made the current 'bar in the Bass. The Gilkes was about double the average graduation thickness when the Top was off and measured. I doubt it was taken down to that point. It was made to be strong and last which is evident in the wood grade, arching, condition and the Varnish which might me made with fossil amber that we have read about.

If it were me and the graduations of a Romanian bass were experimental, I would work around the bar unless the bar was toast at the time of opening. Why do more than necessary. It has worked on old basses before. Why not now.

Oh, and on my Loveri Bows, NO, it is not like how the Amati was named. The Amati was named in error. My Bows were named deliberately, by me after a maker that never made Bows and I have been clear about that. I can spell Sartory too but that would be pushing it. That way, there is no appraisal necessary to certify the origin..:p

[Matthew Tucker]

Ah, but in a fifty years time there will be a rumour going around that Loveri DID make bows, because there are some bows around with his name stamped on them! :p

Perhaps the Amati was attributed deliberately after a maker who never made basses?? :D Anyway, I'd be interested to see the appraisal. Have you seen it, Arnold?

OK Ken, I had mis-read that your tip that leaving the "shelf" under the bass bar was an inherently good thing, instead of just "working around the bar" to improve the thicknesses.

When I regraduated my own bass, I worked neatly right up to the bar, and in fact now you can see the bar and the original glue line raised above the level of the plate. The edges of the bar are sheer and clean right down to the new thickness. If I was to do it again, I'd remove the bar and put a new one on after regraduating. It was very fiddly working neatly right up to the bar, and replacing a bassbar is no big deal in comparison.

[Mike Mandelas]

[quote:I think most luthiers would agree (do you?) that there are probably other things you should try first, like strings/soundpost/tailpiece/tailgut/bridge etc, that aren't so drastic as regraduation. Have you been down that path yet? quote]

Thank all of you for your input. Given my limited experience in regraduating basses i started my experiment with a thorough set up, meaning a new bridge, a soundpost change, a new Marvin wire tailpiece and some stringing options (Spirocores and Corelli 370 Forte). The situation improved up to some extent but i have the impression that the sound is a bit "choked" and rather thin. In violins, where my experience is greater, i solved it many times by regraduating the top plate, thinning it in the appropriate places.

The bass has a thickness of 6.5 mm in the edges (where IMHO it shoud be 4.5mm- 5 mm). Around the f holes it is 7 mm and gradually it increases to 8-9.5 mm. H.S. Wake's plans give in each case a graduation 1-2 mm thinner. I'll post some photos and see.

[Craig Regan]

You may want to get an inspection mirror and check out the bass bar. Make sure its the right size, properly installed, and located in the correct position.

Since the bass bar distributes the vibrations across the top, this could be good place to start your investigation.

[Ken Smith]

OK Ken, I had mis-read that your tip that leaving the "shelf" under the bass bar was an inherently good thing, instead of just "working around the bar" to improve the thicknesses.

When I regraduated my own bass, I worked neatly right up to the bar, and in fact now you can see the bar and the original glue line raised above the level of the plate. The edges of the bar are sheer and clean right down to the new thickness. If I was to do it again, I'd remove the bar and put a new one on after regraduating. It was very fiddly working neatly right up to the bar, and replacing a bassbar is no big deal in comparison.

Matt, in the case of the Gilkes, the platform was outside the glue line about a centimeter or so all around it. I didn't measure it but when the Top was off and before the new 'Bar went in, I felt around the 'Bar and 'Post areas and commented to Arnold how unusual this was. I suggested (which he probably had planned on anyway) that he leave the platform relations as-is during the 'gentle' re-graduation and keep the makers 'idea' as original as possible. The Gilkes was estimated for its wood and arch strength at about 200% the necessary thickness and ended up at about 120% the thickness it would be if made today. The Bass sounds deeper and fuller now and still strong as a tank. The Bass could probably easily survive another 20% of scraping and the removal of the shelf but, why fix what isn't broke? The Bass sounds great now and at 195 years old just needs to be played steadily and break in again. This is a Bass that does not have any belly splits. I plan on keeping it that way if I have any say in it.

[Arnold Schnitzer]

When I regraduated my own bass, I worked neatly right up to the bar, and in fact now you can see the bar and the original glue line raised above the level of the plate.
Matthew, keep an eye on the top in this area. I'm afraid you may have inadvertently created a fault line which could cause a crack. This is the same reason why patch edges should not be finished parallel with the grain.

[Matthew Tucker]

I don't see why I would have created a fault line? The bar is still set at a slight angle to the top grain. If I'd finished the regrad at a sharp line parallel to the top grain, maybe. But the stresses are still distributed exactly the same as they were before, because the bass bar is in the same spot. The top is just slightly thinner, and a little thicker immediately under the bar.

[Ken Smith]

I don't see why I would have created a fault line? The bar is still set at a slight angle to the top grain. If I'd finished the regrad at a sharp line parallel to the top grain, maybe. But the stresses are still distributed exactly the same as they were before, because the bass bar is in the same spot. The top is just slightly thinner, and a little thicker immediately under the bar.

I think Arnold means that if the platform is at a right angle 90 degrees with the Bar directly under it, sitting on it, it acts as a pressure point along the edges or the 'bar joint. I think that is what he is referring to rather than a gentle sloped platform in which the 'bar would sit. That's how the Gilkes is done. You can feel it but you can't see it that easily. It is slight but it is there.

[Arnold Schnitzer]

I don't see why I would have created a fault line? The bar is still set at a slight angle to the top grain. If I'd finished the regrad at a sharp line parallel to the top grain, maybe. But the stresses are still distributed exactly the same as they were before, because the bass bar is in the same spot. The top is just slightly thinner, and a little thicker immediately under the bar.Yes, I see your point. I was thinking the cut-out under the bar was following the grain, but this is not really so. Anecdotally, though, I have seen a bass where the regrad was done this way and the top cracked badly. I remember it being pretty thin. And the wall of old top wood on which the bar sat was a good 4-5mm high.

[Matthew Tucker]

I've taken off from 1mm going to 2mm at the tips. I'm not worried structurally, but as I said, I don't think I'd do it again that way. And your words of caution are duly noted!

[Mike Mandelas]

Here are some pictures of the canditate for regraduation. It has a dense grain in the top plate and a nicely flamed back. I checked the bass bar with my mirror and it seems to be in place, with the proper size. Anyway, when i'll take the top out i'll post some pictures and hope for your kind responses.
Mike

[Ken Smith]

Here are some pictures of the canditate for regraduation. It has a dense grain in the top plate and a nicely flamed back. I checked the bass bar with my mirror and it seems to be in place, with the proper size. Anyway, when i'll take the top out i'll post some pictures and hope for your kind responses.
Mike

Nice wood. Who scalped the Bridge?:eek:

Tight grain and dense wood are not the same. When the top is off you will see if it's heavy of light in comparative weight. Also from the inside, you can test how dense it is with a tool of some sort.

[Matthew Tucker]

Also from the inside, you can test how dense it is with a tool of some sort.

How can you do that?

[Anselm Hauke]

How can you do that?

scratch it with a screwdriver...

[Ken Smith]

scratch it with a screwdriver...

Thank you..

We used to test maple years back when it was hard to tell on some pieced if it was hard maple or soft maple as some of the Sugar maple looked soft. We used our fingernail. If it dented, it was soft regardless o f species. If not, it was hard.

[Mike Mandelas]

I made this "wingless" bridge following some bassists' trend in Brighton,UK. It makes the sound brighter and gives a better arco response. This bridge has considerally improved the sound of the bass.
The top's wood is rather soft, since it is easy to make a dent with a fingernail.
I am in the middle of a serious engineering project so i haven't much time to take the top out. When i'll do it, i'll try to estimate the stiffness of the top plate using my knowledge from violins lutherie. I'll keep you informed. Thanks for all your input.