Eric's New Cello - Making the Back and Top Plates (Cont.)

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Frames (32 & 33) are the beginning of the slower parts of the process. For me it just takes time to get the shapes looking as I believe they should.  Refining the shapes of the arching is perhaps some of the most important work done in violinmaking. The architecture of these plates creates a character of sound and gives the cello its voice. As clearly seen in photo (33), the lower bout region of the arching it still way too full and requires yet more material removed for it to become an efficient acoustical "machine" and a sleek shape.


10/22/2000 - The refinement of the archings with the fingerplanes takes me a fairly long time. It sometimes becomes a case of wanting so much for it to be done ["are we there yet?"], it causes me to start scraping too soon, which I did, thus more clearly revealing to me the areas of the archings which did not reflect the shape I thought I had achieved. In any case, this (34 & 35) is close to finished shape before scraping.
38 39

10/23/2000 - These photos (36, 37, 38 & 39) contain images of the newly smoothed nearly finished back arching. Whew. I'm always glad to have this sizeable part of the project completed. The sweeping up and over and around of the archings was mostly achieved with sculpting quality that the fingerplanes yield. In the previous photos, the way the tool marks are all uniformly right next to each other and the curvature of the long line of each plane stroke, reveals in the shadows a great deal of information about the shape of the arching. The plane stokes are consciously made to create a linear clue to the crosswise and lengthwise shapes. In pursuing the successful resolution of those shapes I run the finger plans planes about four different directions: 1. lengthwise with the grain, 2. crosswise, directly perpendicular to the grain, 3. diagonal across the grain which helps integrate the upper and lower bouts with waist area, and 4. in a concentric topographical layer lines which connects the shape of arching with the outline. Each of these approaches by itself could make a pretty good arch but would presumably miss the correction that the other three attacks provide. They act as a check and balance, maybe. These techniques are something learned, borrowed and adapted from the so-called "lofting" of a boat design, which means drawing the boat full size and by a number of means, this process corrects for inaccuracies that are inherent in a drawing that is then exploded into full life-size.

When the fingerplanes have reached their goal of a good arching, then the scrapers come along. I scrape the surface of the wood, and in the process, smooth out the tool marks and strive for a well integrated surface that undulates smoothly and elegantly without too many ripples or bulges. Oft times, as in a cello back such as this one, there are certain small areas where a number of the flames in the wood have compressed, and in those places the wood is proportionately harder, requiring a very razor sharp scraper to cut it level with its surrounding areas. The scrapers are made of thin spring steel and are flexible enough to bend across the curvature of the arching, thus spanning the high points or hills to lower them to be even with the valleys.

Many parts of violinmaking are strictly structural and must simply be well-fit and sturdily, though lightly constructed. Then there are the various stylistic aspects that are aesthetically important but are more the window dressing. However, early on in my working career I realized that the archings may be the single most responsible members of the whole instrument body affecting its acoustical potential. I believe that how well they are conceived and made, has a very direct affect on the sound of the instrument, as well as the character of the voice quality. With that in mind, I feel it is time well spent trying arrive at a good arching and taking whatever time it takes to do so.



10/26/2000 -  With the outside of the back finished, the inside work begins. Here, (40) the inside of the back is still flat with the inside margins and thickness zones marked on. In (41), the inside of back has been roughed-out and is now ready for the final thicknesses, flexing and tuning. It doesn't look very pretty at this point but will gradually become as refined as the outside. At this stage I will allow the back to "rest" while I do other things. Next I will round the edge on the back. Then I will proceed to do all of these steps on the top, from purfling to finish arching to hollowing out its inside arching, followed by rounding its edge.


43 44
10/29/2000 - The outline of the back and top is initially cut square for the purfling work and then is later rounded. (42 & 43) show the edge still square. The rounding of the edge is begun with the making of a 45 degree chamfer that parallels the outline, as shown in (44 & 45). 


With a uniform chamfers all around the plate, the in-between ridges are removed and the edge begins to look rounded, as in (46). I do the edge rounding with different cut files and a flat bottom fingerplane shown in (47). 



(48) differs from (47) in that the very end of the corner has been rounded - the last thing I do in this process. Too bad I took these two with a light background as it obscures the shape differences. The file marks are now sanded smooth and the remaining ridges gently blended in.  The upper ridge around the edge, sitting halfway between the outside of the outline and the purfling is very sharp at the end of the edge turning work. I like to see this ridge, sometimes called "shadow line", running very true between the outline and purfling creating a cohesive fluidity to these shapes.  Once this line is sharply and clearly established, I like to soften this harsh edge by lightly "finessing" it with fine grit, worn sandpaper.  This gives the edge a friendlier, more touchable appearance, pictures (49 - 53). It seems important to soften this shape without, however, losing the clarity of intent.





11/1/2000 - (54 & 55) The top is made of American-grown Engleman Spruce and is truly a joy to work. These views show the top arching at an intermediate stage of refinement, prior to the purfling, which I will do next.




11/6/2000 - (56, 57 & 58) show the purfling being fitted into the corner mitered. The purfling has already been previously inlaid in the back, so now I am going through identical steps with the top to bring it to nearly complete as the back currently is. I'm not sure if its' really necessary, but I think it's possibly hedge against additional future shrinkage to allow as much time as possible for each of the back and top once they have been hollowed out. That way this task arrangement works out well. Now that the back is nearly finished, I will take the top through all of those processes. At the point that the top reached the same point as the back, I will finish the back, thus allowing the top a little adjustment time.


(59) This cello back has such big wide flames in the maple right in the upper area that what sometimes [often] happens is that those flames will absorb glue in joining. Whenever I use this highly flamed maple, I size or seal the joint with glue after it is first fit. This dries and then because the surface distorts from the moisture in the glue, the surface needs replaning to make a good, invisible fit. The intention is to saturate those flames before the actual, final gluing of the center seam so that under the heavy clamping pressure, they don't keep drinking in the glue, thus starving the joint leaving virtually no glue between those areas of heavy flames. Alas, in spite of my best efforts, this area of the back with such deep figured maple, snapped a tiny bit when I exerted pressure on the inside with finger plane, opening only the outside for about a 3" length. So it became necessary to reglue this area. Typically, the actual joint surface is extremely well fit and already now saturated, so that re-applying new glue and clamping restores the solidity of the joint amazingly well. The danger, however, is that this very beautiful and deeply flamed maple is now in its finished shape, fresh from the sharp scraper and all of the pores of the wood are still highly vulnerable, standing wide open, awaiting the bare wood preparation and sealer to be applied to enhance this very receptive surface. Glue can so easily be soaked into the grain at this point and even thorough washing with hot water afterwards will not bring the wood back to this pristine state once glue has soaked in. Were it to not be protected in this manner with Scotch Magic Tape laid either side of the center seam and nearly touching to prevent any permeation, there would doubtless be a very unsightly blob in the middle of the back after the initial sealer is applied.
60 61

(60 & 61) The final planeing and shaping of the top arching with a fingerplane.




11/26/2000 - Finally I've gotten back into the shop and these are the finishing of the outside arch of the top with the scrapers. This process does not seem to show up very well in fotos.




12/12/2000 - Image (65) shows the F-holes traced onto the otherwise finished top. They are laid out so that the inner notches [they don't show much right now] are in the indicator marks for the bridge location, also known as the "stop" or the "mensur". In (66), the eyes of the F-holes have been drilled and roughed out. I've used a fine coping saw in (67) to saw around the outer perimeter of the f's connecting the lower eyes with the uppers eyes and have started splitting out the waste wood, which continues in (68).

68 69 70
 In (69) I've cut in the body of the F-hole with a sharp knife. The ends of the F-hole wings are split out in (70), which are trimmed in (71) to form the roughed-out F-hole. (72) shows both F-holes. At this point, the F-holes are a bit rough, slightly unrefined. I will finish that tomorrow in the bright sunlight to make the curves more fair and smooth.



12/14/2000 - The F-holes are hereby pronounced "finished", as shown in #'s (73 & 74). Pronouncing them as finished is something of a formality and a way of saying it's time to move on to the next step namely, the bassbar, as I will typically find nearly endless little areas on the F's needing additional slight improvements.



Fotos (75 & 76) show the bassbar fit and glued and clamped into place. Tomorrow I will take off the clamps and trim down and "tune" the bassbar.




12/15/2000 - With the clamps removed from the bassbar, the trimming of the bar begins as on the left side of the bar in (77) and the right half of the bar is still the straight board as glued in. (79) is the bassbar as a nasty, bull-in-a-china-shop brute. 
80 81


(81) is tapping the top to hear the tap tone of the bassbar. I'm listening to it become more clear and focused, as well as flexing it to feel its resistance. (82 & 83) are the bassbar tamed. With the final rounding of the edge, as pictured in the back fotos, the top is finished.
This page was last updated 01 April, 2001 02:55 PM
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