nathan slobodkin

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Everything posted by nathan slobodkin

  1. Hi Jeff. I bought some of the spiral reamers from Dick(?) but quickly realized that a right cutting cutter with a right hand spiral was a recipe for disaster since it tends to self feed. A right cutting reamer with a left hand spiral however might really work great especially for thin or incomplete bushings which are the only time I find the straight cutters tend to catch. Any one know if someone is making these?
  2. Likewise. Did you send them the additional 50 bucks for shipping?
  3. Jacob , I just read your link to the neck tilt discussion and don't blame you for not wanting to rehash it. Very interesting however and I once again have to thank all who contribute to this forum. It's a far cry from discussions with early teachers which ranged from "because I said so" to a (mock?) slap followed by "Shut up! He explained".
  4. You are right of course thanks for the correction.
  5. I was sharing what was the standard practice in Rene's shop when I worked there. Actually I have stopped using T-nuts on cellos but still would use them on violas with cello style scrolls although on my instuments I don't make those either because I think smaller lighter scrolls are less tiring for the player.
  6. I beleive most well trained technicians would be aware of these adjustments. Because the A string hight off the fingerboard is lower the bridge may look like it tilts toward the A but if it actually does then you should have it fixed. By the way on new instruments I find the best way to achieve this tilt is to carve the scroll from a squared block then lay out the neck heel as if it will be set with no tilt but then to plane the tilt on the surface of the neck block before gluing on the fingerboard this means the scroll is still lined up staight on the cello but the required tilt is achieved on the board. On old instruments you can plane the bass side of the fingerboard thinner as long as it's thick enough.
  7. I worked in Rene's shop in the early 90's. At that time we always set the strings slightly toward the bass side of the nut to give a bit more room on the A side and keep the fingers from sliding off the fingerboard. We also used to put a T-nut on every cello which we reset or grafted necks on. That meant that the nut was extended down the neck 3mm. or so which keeps the player from rapping his knuckles on the shoulders of the scroll when shifting backwards to 1st position Lastly the neck was always tilted slightly down on the C side to effectively raise the A in relation to the other strings and give more bow clearance on the A so you don't hit the C-bout of the cello with the bow. Which direction are you shifting when you "run out of real estate"? It sounds to me that unless someone actually changed the string length you should be able to get your instrument back the way you like it without major surgery.
  8. Hello Wolfjk, why would raising the neck pitch have anything to do with the fit of the bridge feet??
  9. Giovanni Your question about bridge width is a very interesting one. I was told by Rene Morel that since instruments which have wide set FF holes are usually too stiff in the center that using a wide bridge and or a wider set bassbar further increased the resistance of the instrument to the sideways rotational force delivered by the bowed string and was therefore counter productive. This discussion was regarding a Montagnana cello which he had moved the bass bar inward and then used a 90mmwide bridge instead of the 94mm which had been on it. I think that if you cannot move the bar then a slightly higher pitch and bridge might apply more leverage to get that stiff top moving and I would use an apropriately wide bridge to match the bar. I'd be very interested in hearing from some of the more experienced restorers on this subject. By the way Aubert does make deluxe bridges in both wider and narrower widths for violin as well of course as viola and cello.
  10. bcncello, You are correct that the smaller angle below the bridge results in greater downward pressure and perhaps a greater deformation over time if all other things are equal however your asertion that lessening this pressure is advantagous is not necesarily so. The amount of pressure on the top is crucial to the sound of the instrument . I don't usually measure the string angle over the bridge but after making well over 100 cellos I can tell you that a pitch (distance to the top at bridge position from a line extended along the center of the fingerboard)of between 78 and 83 is almost always going to work. The arch hight, neck angle, overstand and saddle hight all effect this.These things are done for acoustic reasons, as far as reducing top deformation arch shape, graduation, bass bar strength and spring are the apropriate way to help with this.As a maker my job is to make great sounding instruments that are still strong enough not to deform or fall apart over the next 100 years or so, after that they're the restorers problem.
  11. Are you saying not to use excessively light tailpieces or are you referring to the comercial "ultra-lite"tailpieces? If the latter I use these extensively on student instruments and have had no negative feed back from teachers. I have just recently however had two of the sacconi style tail festeners which come with them break which I beleive is from the nylon being kinked in packaging. I am now using nylon hangers from a seperate source on these until the packaging issue is solved.
  12. I agree with Jeff H. that the first step is to make sure you have clean, flat, filled surfaces both on the underside of the top as well as both the glue surface of the ribs and the side of the rib where the "fillet" builds up. You really do have to remove this or retouching is very dificult. After the top is glued make sure there is no glue left in the corner then color any new wood or filler to match the old wood. Now seal any bare wood and retouch under the edge with apropriate pigments followed by a very thin fixing coat of spirit retouch varnish. Finally mix burnt umber or other oil paint to the right color and paint a very smmall amount into the corner where the top overhangs the ribs. After a few minutes wipe of all the paint except for a fillet in the corner and a light glaze under the edge to kill the gloss of your fixative. This gives a very undisturbed look. By the way Lyndon I think half strength glue is still way to strong for tops. In my shop I rotate several glue bottles from fresh mixed for centre joints and necks then slightly weaker for backs to ribs etc. and finally old smelly stuff thats been watered down for a week or more. Thats the stuff I use for tops and find it plenty strong but can be opened with no damsge especially when blocks were sized during construction or on previously glued joints.
  13. Thanks David. For some one who has worked alone for so long and who was trained in a shop where production was valued far higher than discussion it is a real eye opener to have joined this forum. I'm realizing that there are a lot of very interesting dialogs going on and am enjoying the challenge of questioning some of the things which I swallowed whole as an aprentice and have never really thought about. Thanks to all of you!
  14. Hi David, If the higher arch tends to have a greater resistance to bridge pressure do you compensate for less stiff wood by going higher on the top arch? I have always done this but have never really examined the reason. Like wise as I asked in my previous post does it follow that a flatter back would resist sound post pressure better than a higher one ? I hope you are still following this thread as I would really value your opinion on this
  15. Joseph, You should be picky about wood but it will take some experience to find out what you prefer. If you look at nice instruments you'll see both very fine grain and wider grain especially on larger instruments. You can usually compensate for stiffer or less stiff wood with your graduations. What you do need to insist upon is wood where the fibers run straight down the edge of the billet. This is a function of either splitting the billets from the rounds or carefully sawing parrallel to the split. Since opening up the billet as a book match doubles the error as little as 5 degrees of run out will result in the two sides of the top having radically different stiffnesses especially in the ends of the plates where the arch angles downward. I'd also try to deal with cutters or suppliers who give a neatly cut slightly oversize billet with sealed ends and smooth planed or cleanly split surfaces to let you see what you're getting. Simeon's wood is nicely cut.What I bought was on the light and fine grained end of things. Good luck with your instruments the first hundred are the hardest
  16. There is way more variation in strengh of spruce than I ever expected. My own deflection tests using squared sticks and weights showed up to 30% differences between different types of spruce and as much as 10% between different pieces from the same log. I always look for moderately strong spruce and buy enough of the same log so I can make as many instuments as possible from the same stuff. After three or four you can really get the feel for how thick to make stuff also would point out that arching shape probably makes more of a difference to the fiddle than a tenth or two of thickness and what we're working with is the stiffness of the plates when put together and under tension. In my opinion the softest European or Adirondack will be softer than hard Englemann so you really have to evaluate the wood your self.Also as I said in another post a while ago Properly cut wood is absolutely imperative.
  17. Bruce, Reading your post about the changes to an instrument when it's strung up I agree that the change in the neck pitch is from longitudinal compression of the top but most new instruments need a longer sound post after a fairly short time and usually another within the first couple of years.This for sure means that one or both of the plates must be bending outwards and if it's the back you wonder what could make it bend further than the soundpost pushed it especially since the longitudinal stretching should provide at least some flattening (and upward) force. Likewise have always assumed that if all other factors are equal a higher top would be stronger and more resistant to downward pressure but am not clear about how back arch hight affects resistance to sound post pressure. Physics anyone?
  18. Melvin, thanks for info on sharkskin. To translate from English to American are you saying to use parrafin which Americans would call wax? Or are you referring to parrafin oil which I think would be kerosine in the U.S. Also thinking that the stuff must dry stiff do you soften it before use?
  19. Hi Roger, Could you please Give a description of how to process dog fish skin? Does the size of the shark give coarser or finer abrasive action? Thanks
  20. As to whether it is possible for Del Gesu to have worked in the Stradivari shop an over veiw of DG's work as a whole shows that he certainly had the skills to follow another makers style as indeed any properly trained maker could. There are at last count 13 different labels attached to my work and while those with my own label or a "made for"label show my own style and judgement the ones where I was simply another pair of hands show the style of my employer close enough that they were comfortable putting their label on it. Also the idea that Stradivari (or the products of his shop) were technically perfect is simply not so. I have seen one rather famous Strad cello where tool marks from a saw, a tooth plane and a scraper were all visible in one six inch area.I think that the Indiffernt workmanship sometimes seen on DG's work is a function of economics, possibly ill heaslth or infirmity and maybe that he valued function and shape over surface details.
  21. The question about whether the insides of violins have the corduroy effect is an interesting one. My own recollection of the inside of classical instruments is that I've never seen the kind of strong uniform corrugation on the inside that I've seen on the outside. In my own making I know that while some corduroy is inevitable with scraping the really strong effect requires a deliberate effort. There are several mint condition instruments that I have seen that I am sure were made to deliberately maximize the corrugated effect. The nicest example I can think of is a Venetian violin at the shrine to music museum I beleive a Linarol. I have also seen many fine instruments where there was a deliberate use of texture to acheive certain effects for instance a great F. Ruggieri that had the most plastic and fluidly carved scroll where the fluting was not scraped at all but finished with a gouge alone leaving a random pattern of 1 to 2 millimeter gouge marks all over. Since there is no question that these guys had the technical ability to make things as smooths as they wanted to the only conclusion I can beleive is that the surface we see is the one they intended.
  22. Tom, Have you discussed these issues with the maker of your new violin? I would certainly show him/her the two violins together and try to explain what you are feeling. There may be mechanical reasons for the different comfort level or it may be that you are hearing perfomance problems on your "better" violin that weren't audible on your old one. I have often had the feeling that some instuments which my professional clients love required more technical ability than I as a college level player at best simply did not have. I hope that this comment is not discouraging as you may find that by learning to play your new violin your performances may surpass what your old violin was capable of.
  23. Salve, your comment that the denser winter grains of spruce would shrink more than summer wood upon drying make no sense to me the larger cells of the summer wood have thinner walls and more space inside which would be filled with liquids and would collapse as the liquids exited the cell giving the opposite effect from what you describe. As stated in several posts yesterday the corduroy effect on violin tops is caused by scraping to smooth the wood rather than sanding if you want to get some other surface you must do some further step such as sizing the top with glue and rescraping after it drys. The comment by Melvin that we don't see the corduroy on trade violins is that those violins were sanded either after or instead of scraping.
  24. Enthusiast Yes you can wet the spruce to raise the grain even more but as the other participant said the grain will raise by itself. If you do wet the spruce and dry it with a hair drier you will have the lower hard grain and a rounded, swolen soft grain between the hard grains. If you then take some 400 grit sand paper on a wood block and sand the top just enough to flatten the tops of the soft grain then you get a very uniform wide wale corduroy look such as we used in the W.H.Lee shop where Mike Darnton learned it. I have also seen very similar results on mint condition classical instuments.
  25. The look of many classical violins is of a top which has been scraped so that the winter grain cuts while the softer summer grain compresses slightly then pops back up so the winter grain is below the soft grain and you have a corduroy effect. The varnish then builds up in the lower hard grains and results in the corduroy effect being excagerated or as the instrument is rubbed down either by the maker or by time you may get a fairly smooth finish with darkened winter grain.