Jump to content
Maestronet Forums

Bob Spear

Members
  • Posts

    114
  • Joined

  • Last visited

Profile Information

  • Location
    Ithaca, NY

Recent Profile Visitors

4585 profile views

Bob Spear's Achievements

Member

Member (3/5)

  1. Slightly tangential to the discussion, but friction between the tailgut material and the saddle is something I try to avoid for reasons that have little to do with the endpin. I want to eliminate all upward pull on the saddle because in time the tailgut will pull the saddle away from the block. A touch of paraffin will do it, although I have taken to using a half-saddle in recent years, which also helps enormously. As for bushing the endblock, it's a lot easier than replacing the end block and drilling a new hole. Some of the cello endpin assemblies require a maximum hole into which is fitted a rather substantial steel sleeve. They don't bend, but they do work loose! Maybe a good place for a little extra sticktion? Like all things with the violin, the tried and tested ways work really well, but when conditions start to decline I think a little bit of reaming and a slightly larger endpin is an excellent solution.
  2. A well-fitted endpin should last just about forever, if not longer The end pin plugs in the larger instruments have to be larger to accommodate the 8mm or 10 mm pin rod itself, If they are too slender the pull of the tail cord will bend them enough to cause the rod to bind. It is entirely possible to bush an endpin hole. I've never used fiber or other materials for this, but if it works on peg holes, it should work on the endpin holes as well. A stronger material will only serve to straighten out the tapered hole. It's the pin material itself and the precision of the fit that matter most.
  3. I think that Joe's ground system produces the best results of any system that I have ever used. Don't fear the yellow/gold in the ground process, and remember that the sun is your friend. One other feature to remember if you are not a fan of oil varnish is that the ground takes spirit varnish beautifully, too.
  4. I used a duplicating router for several years. It lived in a corner of my basement. When all went to perfection, I could rout out the tops and backs, both inside and outside, of three pairs of cello plates in a day. At the end of one particularly glorious session, my hands were tingling, there were wood chips over my ankles, and my router was smoking. My wife came into the room with shooter's muffs on her head and said, "We are not doing this ever again!" The major drawback to the duplicating carver is that you need a master to use when carving the blank. If you are going to go to all the trouble of making masters for the top and the back, they should be very durable so you can use them again indefinitely. Unfortunately, wood is prone to warping, so be advised this device save you a lot of time on one end and costs you a lot of time on the other.
  5. For what it's worth, I moved to using a constant radius some years ago, but I think I came to this decision from the opposite end. Modern virtuoso writing for the violin pushes the player into the far regions of the fingerboard and requires string crossings in very high positions. Looking at the end of a fingerboard blank and at the arc on my trusty bridge template, which I have been using since the mid 1970s, I finally saw that they didn't relate to each other in a way that would be useful in this situation. The height of the middle strings was higher than the height of the two outer strings, so it presents the players with difficulties playing the middle strings both in the amount of pressure needed to get the string down on the fingerboard and to keep the bow from hitting the next nearest string. So in a moment of weakness, I took the arc of radius from the player's preferred arc of the bridge and went from there. The idea was that the A string is a little higher over the end of the fingerboard than the E, the D higher than the A, and the G higher than the D. Then I tried to keep this radius all the way to the nut. The result was a fingerboard with a tighter arc than we see on the commercial blanks. As others have pointed out, deviations have to be made for various reasons. However, the greater or lesser arc of radius at the nut end never bothered a single player. The amount of work required to do a board this way is largely useless if your player isn't in that league. Also, the larger the instrument, the thicker the fingerboard needs to be in order to keep the edges of the fingerboard from looking strangely thin. It also means that the fingerboard arc would be different for a five-string bass than for a four-string model. As for the scoop in the fingerboard, that's a challenge, especially if the player does a lot of pizzicato. I once dressed a fingerboard for a player who wanted his top string at 3 mm above the fingerboard. I said, "Joe! (not his real name) That's what I set for a violin!!" "Joe" was unmoved, so in the end, I planed and scraped the fingerboard, removing and replacing the string to the point where the buzzing stopped. This I did for every note on the board. Yeah. It's crazy. But when I was done, the shape of the board was organic, and it gave me a great insight into where the string excursion is the widest at each note. Life is too short, or else I have to charge more for this.
  6. Hold on, guys. Major misunderstanding here. I meant no disrespect to Don Noon. I would be happy to have him visit my shop any time, (as I would the rest of you), and I would be happy to visit his, should the welcome mat be out. I think he and I would find that we have a lot of the same ideas, but perhaps we pursue them in different ways. I'd like to explain that the comment about the 300 bass bars is part of an old joke about mastering difficult processes. It's been floating around the violin world as long as I have. In any case, the original post in which that comment appeared was not directed specifically to any individual, but to the topic. The subject of the paragraph was the difficulty (or lack thereof) in fitting a bar well. If the paragraph is read correctly, one can see that I directed the comment about the 300 bars at myself. The portion that appears in my reply to Don clearly refers back to its use in my previous post. Without that, the first sentence would make no sense. Curious1, your misreading of the thread could imply that all sorts of things exist between others on this forum that might not be true. First of all, I've never "played games" with any friends or colleagues on this forum or any others. Second, read the thread again and point out to me the part where I claimed to know more than Don. Third, it would be better to have said "It seemed to me that Bob (true) . . ." rather than "Bob seemed to be (false). . ." which confers a kind of vague and free-floating approbation on the situation that might not be true.
  7. That the final state should be the same as the beginning state, or that it gets easier after you've done several hundred? (Sorry, Don. I couldn't resist! ) But, a fair question. I never kept records because when I started doing this I wasn't aware that records would be helpful..I did come to notice that in many cases, though not every case, the "all-equal" instruments sounded better. I think it odd that one would put a huge amount of work into a free top only to slap in a bass bar with the idea of changing something. Change to what? My own experience indicates that trying to correct for a deficient top with the bass bar is largely a waste of effort.
  8. I follow more the "hump of the whale" concept when placing the high spot of the bass bar. Putting that spot under the bridge foot aligns it with the inner notches of the f-hole, which results in an asymmetrical bar with the longest leg extending far into the upper bout. Generally speaking, the weakest part of the top lies directly between the upper eyes of the f-holes. That's where the most support is needed, so I generally try to advance the high spot in that direction. This will place the bridge foot a little behind the bar, which I have found does not compromise the bar's strength. It also moves the high spot more toward the middle of the instrument. I think it looks better, too, for all the players in the future who will be contorting themselves with flashlights and mirrors to see what you did!
  9. As a luthier and a student of Carleen Hutchins, I was amazed at what this filmed showed regarding what we now call "free-plate tuning." Like many "discoveries," we find out that much more was known much earlier than we believed. Since the first motion pictures with sound appeared in the 1920s, and this film was "approved" by the National Board of (Movie) Review, formed in 1909, we can pretty well determine when the film was produced. The major free-plate modes of a violin (1, 2, and 5) can all be excited by bowing. No electricity or special equipment needed. Seeing it in the film shows unarguably that this form of plate tuning has been used for at least a century, and probably even longer, in the shops of violin makers and out of the realm of scientific hypothesis. Seeing that Rembert Wurlitzer was a student in Carlisle's shop goes a long way toward explaining why Hutchins received a friendly welcome at Wurlitzer's 40 years later. Wurlitzer already knew about the process and probably appreciated its value. Now, all we have to do is find out the name of Carlisle's teacher!
  10. I ask my students to consider not only what a bass bar is, but also what it does-- that is, what purpose or purposes does it serve? In the main, I believe that there are two major functions of the bar. The first is structural, and the second acoustical, although the order in which you address them isn't critical. The best installation of a bass bar will return the top plate to the condition it was in before the f-holes were cut. This requires some tuning of the bar, but it's not difficult. As my teacher used to tell us, after you have fit and tuned 300 or so bass bars, it gets easier.
  11. Fitting an endpin is not very much different than fitting a peg. It is also an extremely easy job even in a lightly equipped shop. In more than forty years, I have come to almost never expect to see an endpin glued in place. Those I have seen usually come from fiddlers who live in isolated areas and don't have access to the skills and experience of a good repairman or who might not even know that the part is replaceable. And I have never, ever, ever seen a glued pin on an instrument of value. Removing a glued-in endpin is potentially a not very easy job. Sometimes endpins are fit so tightly one might think they've been glued in, leading some to the "twist-it-off-with-a-pair-of-pliers" technique. If the pin is, in fact, glued in place, the results can be less than amusing. A violin is a delicate instrument. No beating, banging,or wrenching is ever done in my shop. If a pin is in that hard, and there's no way to know if it is glued (or what it might be glued with), we cut it off and drill it out.
  12. We all know what wax is. Slippery. Its presence in spirit varnish probably gives a slightly softer luster to the varnish than does shellac alone, but I suspect it degrades adhesion (although not enough to make us all stop using it ). The earlier and simpler way of brewing your own varnish allowed one to remove the separated layers as one wished. Taking the waxes out might also have led to simple and dependable recipes like 1704 where other gums and resins were substituted to give the same effect. For brushability, adding oil of spike can achieve the same thing. To cook or not to cook? I've brewed it cold, left it in bottles on my shop window to warm in the sun, and cooked it. I have to say that except for cooking's faster result, I didn't experience any noticeable differences between the batches. When cooking varnish, most of us go outside and use an electric hot plate with a fire extinguisher close at hand. With alcohol, things can go wrong very quickly, so I pass on that step and make enough so that time can work slowly on it. For elemi, spike oil, and the like, I use a double boiler on a stove at a moderate to low heat. We have to remember that varnish ingredients are natural substances. Age and other conditions require that we modify the process to suit. So if the ingredient is old, hard, or dried out somewhat, might as well cook it. Otherwise, there are safer (but longer) options. BTW, hardware store paint strainers work very well as a filter. Their conical shape makes them ideal for use with bottles that have narrower openings. I can get several cleanings and reuse my filters, but when they get hopelessly clogged they're inexpensive enough to throw away and replace.
  13. Taking a lunch break from exhausting myself at the bench working on a bass back. Can't say all I want or I'll go back to work hungry, but it's a given that all violin makers over time have "tuned" their plates. Either that or the tens of thousands of instruments that have been measured over centuries have all been regraduated! Earlier makers had two tools at their disposal; 1) their hands, with which they could feel the wood by of the plates by twisting and flexing it, and 2) their ears, with which they could hear pitches as they tapped the violin plates in different places. With the Hutchins method, a very important third tool appears-- the maker can now SEE the patterns in the wood. It shows one how the modes move and what they look like while one is working! Cause and effect now more clearly revealed. Why one would choose to remove this valuable a tool from their toolbox truly baffles me. Don, did you notice how guarded those researchers were in stating their conclusion? In two out of three cases very clearly stating not that such relationships did not exist, but just that they couldn't find them. Not the same thing.
  14. Jim, the point of graduating a top or back is to remove all wood that is not contributing to better performance while at the same time not removing so much that structural deficiencies occur-- two aims that are often conflicting. In this phase I have never found anything that works better than Hutchins-style plate tuning, real old-school stuff with a loudspeaker, a sine wave generator, a little bottle of party glitter, and all brain cells operational. The actual frequencies when you decide to stop are relatively non-critical. If mode 2 is 180, or 170, or 160, or even 155, your violin will not sound like a viola. All plate frequencies disappear when the ribs are glued on, all the numbers change, and all the patterns change. Just like the staircases at Hogwarts. What does not change is that you have plates that are optimal for their purpose. It suggests to me that a very fruitful area for exploration, one that will allow the maker to have some control over what he's making, lies in the construction of the ribs because the ribs have a commanding influence on how the body bends and twists. I understand the argument that if everything changes, matching frequencies and modes in free plate might be a waste of time. But I have over forty years of experience that argues strongly to the contrary, coupled with over forty years of puzzlement over why that should be. I am also realistic enough to know that while my last 20 violins continued to support my observation, my 21st violin, the one I will be showing to all my contemporaries as a fine example of the process, will be just awful!
  15. Jim-- violin body length is, say, 356 mm or thereabouts. Divide by 12 and get 29.666 for the rib height. What the hell . . . make it 30 mm. Divide 30 in half and get 15 for arching height. Some advocate making the top plate arching at 16. I doubt this is the result of stringent acoustic testing, but rather of observing the forces that stretch and deform plate arching over a hundred or so years of playing. Keeping it simple is my own favorite approach, too. Basic Hutchins-style free plate tuning is very helpful here if you don't get hung up on the numbers and simply tune the plate for maximum glitter activity, symmetry of pattern, and refinement of nodal line thickness (not necessarily in that order). This goes a long way toward getting the most out of any decent piece of wood without getting into specific gravity, speed of sound in the wood, and so forth. Not knocking science here, having done some myself, just saying that it is sometimes possible to know too much.
×
×
  • Create New...