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PASEWICZ

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Posts posted by PASEWICZ

  1. Just now, violins88 said:

    Jerry,

    I respect you, and I respected Professor Baldwin.

    i shall wait for the experimental results. I can’t do the experiment this year, since I am in New Zealand. Do we have any volunteers? Someone? Anyone?

    I guess my question is, why do we have to make a choice of either or?  Isn’t it obvious that a neck that is set well is more likely to stay put without breaking the button than one set poorly and only glued to the button?

  2. 2 hours ago, violins88 said:

    To answer the question of the importance of the button in holding the neck from collapsing, I propose the following experiment:

    Take any violin with steel strings. With the strings tuned to pitch, somehow freeze the pegs so they won’t move. Measure the end of fingerboard height above the top.  Now make a saw cut at the base of the heel, effectively separating the button from the heel.

    Now put the violin in a safe place for a long time period ( a year?).

    measure the fingerboard height again. Report back to maestronet. If Professor Baldwin is still alive, I will try to report the results to him.

    We have been setting necks as a profession for a very long time.....there are not any mysteries.  A well fit neck will stay together without damaging the instrument far better than a neck where one only relies on the button.....how was Professor Baldwin with statistics?.......... 

  3. 1 minute ago, Mark Norfleet said:

    Cool tool.  Thanks for posting the pictures.   It's easy to see why this is an improvement on using a lathe.

    Do the drills wander at all and produce less than perfect holes?  I would be tempted to use solid carbide bits if so.

    The drills are great, no drift and it puts the hole right where you need it the first time.  Every bow maker knows how frustrating it can be to keep bushing a screw hole on a new bow because the drills do not track.

    There is another cool thing about the tool.  He included fixtures that have step up concentric circles cut by the 1/10 of a millimeter (you can see them on the 2nd photo on the right). You put these into the tool, and rest the proper concentric circle on the v block.......so, if you want to drill exactly on center of an 8.5 mm stick, you set the v block to rest on the 8.5 mm concentric circle, and instantly you drill dead center....pretty brilliant.

    Finally, one thing Alberti does not do is send instructions.......these things arrive in a box and then it is up to you to figure them out.

  4. 44 minutes ago, Mark Norfleet said:

    I don't see that tool on their website.  Is it no longer made?  Mostly I'm curious about it.  I've no plans to resume bow repair, though there is a need for that in my area.

    I do not know if it is readily available yet, I have had a second on order for quite some time.  I will post a pic when I am back at the shop. 
     

    Okay this is it:

    796FC616-CC6A-4BF3-9327-5C6046780FFE.jpeg

    99D03081-3CC7-4A6D-8808-A5A93DA885EE.jpeg
     

    The bow rests on the v block on the the 2 90 degree frog underslide surfaces.  You can see the drill mocked up, the placement of that is adjustable to where you want it.   
    Basically, it is like putting the bow into a v block on the lathe compound and moving it up and down to get where you want to be.

  5. 27 minutes ago, David Burgess said:

    It can, with a good fit and the proper glue strength. You can test this if you wish by using a waxed paper separator to prevent adhesion between the neck and the button when you glue in the neck. Again, it has to be a good fit, and I would recommend not diluting the glue to a point where it takes more than 60 seconds to begin to gel. And prior to fitting, glue size the end grain at least twice... as many times as needed for it to absorb no more.

    Which is why we use a pigeon posterior junction for strength......

  6. I use compact 8 lathes mostly.  It is nice to have a lathe that allows the making of tooling when needed......it does not seem that a sherline Is nearly strong enough to cut teeth in cutters.

    I did see the Taig at camp last year, it is an impressive little tool.  

    The Alberti stick bushing tool is by far the better option for bushing sticks; it can do in short order what takes forever in a lathe, even with a four jaw chuck..

  7. Joe Regh asked me if he could have a tool made up for sale based on our technique which is outlined in the IPCI book. Since that time I have had nothing to do with the tool or the sales thereof.  At first Joe sold the tool with metal rings, which is not how the technique was developed and is not something I would endorse.  A few years back I was able to find a manufacturer that would make the carbon fiber rings with the orientation required .....You can certainly get them from Joe, as we sell the rings to him

  8. We also use end grain to end grain here as well as a matter of good conscientious work practice.  Having the grain oriented the way is is on this piece likely contributed to the failure; with competing expansion and shrinkage orientation the joint was bound to fail.

  9. 20 hours ago, Brad Dorsey said:

    I assume this would require repeatedly putting the eye in the hole in the frog to check the fit and the concavity then taking it out to adjust it.  But whenever I try to put an eye in a hole and take it out:  1.  If the eye is too big I can't get it in the hole, of course;  2.  If the eye fits closely the way I would like, it's almost impossible to get it out; and  3.  If the eye is small enough to remove it easily, the fit is too loose.

    So how do you fit the eye before gluing it?  Specifically, if the eye is the right size for a good tight fit, how do you get it out to work on the concavity?  And once you get it out, do you file it to make it concave?  If yes, how do you hold it while filing it?

    The eyes on bows are cut with basically a spade bit.  Many times when the old eye is cleaned out, you will notice the pilot hole goes into the mortise.  For these cases I have a dental tool I have ground and shaped like a hockey stick. I can put that into the mortise and punch out the eye from the inside.  For tough eyes that do not have a hole, I have a couple different strengths of double sided mounting tape that get put onto different diameter drill rods.....I use the strength of tape that is appropriate....if it does not work I kick it up a notch.

    For shaping the concavity,  I have a short (4”?) piece of 2” diameter PVC that I have heated and bent to be egg shaped instead of round.  I also will use glasses, cups, cans, or any appropriate radius.  Then, I mark the eye on the inside face with a sharpie which edge is the rail side, and while holding a piece of 600 on the radius object with my left hand, I index the the eye against my right middle finger and sand moving up and down to the desired radius......only radius. Once the radius is set, I mark my  rail side edge on the radius side and take to thickness on the flat side of the eye.

    Happy New Year to you Nate.  I do not mind putting on the acid after it is glued, especially because the eye is already below the surface so the drop you put on does not need to span the entire eye.  Obviously doing the acid before gluing is safer if one is not confident in their dropping skills........

    Also, eyes do not need to be tight.  When replacing an eye, it is rare that the edge of the hole is still sharp and not at least a little rounded over.....making the eye slightly under the surface to coincide with this wear eliminates the need for a tight fit, and making the eye incredibly tight up to the surface will never make the eye look like a good fit.  When the edge is sharp, it is likely a new bow with an eye that fell out... the maker of the bow made really tight eyes then glued them by putting thin CA over the top starving the joint.......hide glue prevents this as you put the glue in first which allows positioning.

  10. We use Nitric on already wet pearl...this gives a nice etch without accentuating the stress marks you can get with some pearl.  The key to putting in pearl eyes and not damaging the frog is to fit the pearl eye before gluing......completely, then glue with hot glue.  It is real difficult to damage a frog when there are no tools close to it......using CA as was mentioned will leave a white line in the joint after cleaning, and if you are lucky enough to remove the white line, you end up with a shiny ring surrounding the eye.  Tape will leave the eye slightly above the surface when you are looking to get an eye appropriately below the surface (before acid).

    ...finger eyes should be slightly lower than thumb eyes for those with an OCD advantage.....

     

  11. 19 minutes ago, Michael Darnton said:

    The only "available evidence" I have in this regard is actual bridges showing that the best wood can warp if the bridge is cut wrong or not maintained and the worst wood can stay straight if the bridge is cut right and properly maintained even after heat straightening, so any theoretical evaluation of wood strength has very little to do with the issue, in my experience. This basically removes theoretical measurements from the question.

    On the other hand. I have seen lots of violin bridges collapse straight down, which brings up some more questions. But not cello bridges. I'm in the middle of getting a handle on this for violins, but the evidence so far is indicating cutting errors, in that I'm seeing this in supposedly good wood from supposedly good shops, consistently. The examples I've seen I am pretty sure have never been subjected to straightening.

    Actually, this brings up another question: I know that a lot of shops cook bridges as part of the cutting process to give them a bit of color. IF heating wood damages wood . . . but the people who do this maintain just the opposite. . . .

    I agree, if the bridge is cut correctly and maintained than none of the issues regarding strength is relevant. The strength issue has to do with the cellular structure collapsing and then never being able to fully "un-collapse.  The dry heat for cooking bridges might be an issue, although more research would be needed to be relevant to what we do.  As far as violin bridges, I have been working with this issue for a while because of bridges sinking at the e string kidney.  Moving the center-line between the kidneys toward the e string to equalize the downward pressure would certainly do the trick, but I do not know if having the pressure balanced at the kidneys is a good thing or a bad thing. 

  12. 3 hours ago, jacobsaunders said:

    One doesn‘t need any heat at all to straighten a cello bridge. Blimey, you will be dovetailing it next!

    Yes Jacob, I suppose “one doesn’t need any heat” if the goal is to turn a 10 minute job into a 3 day ordeal.  I guess my brain is not set up to think of ways to take as much time as possible to do as little as possible.

  13. 10 hours ago, Michael Darnton said:

    I wet a paper towel, fold it to the dimensions needed to correct the problem as locally as necessary, put that on the microwave turntable with the bridge's concavity appropriately sitting on the wet towel, and nuke it in 15 second increments until the problem straightens out (which happens most of the time but not 100%). Then a few seconds of nuke of the bridge standing dries it out, and back it goes.

    Warning: without adding water, a bridge will burn before you know it, and from the inside out, so by the time it's smoking, it's too late.

    When this doesn't work, I follow by bending against a hotplate with a1/4" sheet of aluminum on it. 

    Additionally, I have heard, many times, that a bridge that's straightened is weak and will bend again. I regard this as TOTAL NONSENSE. 

    “High temperatures may result in some permanent loss of strength, the extent depending on the temperature reached, the duration of heating, the heat source, and the moisture content of the wood.”

    — Understanding Wood: A Craftsman's Guide to Wood Technology by R. Bruce Hoadley

    “TOTAL NONSENSE” Does not square with available data, and it is my experience that bridges warp quicker after straightening this way if no other remedy is attempted.  However, heating wood without the moisture to close to ignition momentarily does not show reduced strength...... try quickly heating the bridge and bending it dry......not in a microwave!  This of course cannot fix the reduced strength from the compression of the wood.

  14.  

    3 hours ago, Johnmasters said:

    Doesn't it seem reasonable,  that if amount of hair in the ribbon is critical,  one should ask whether one wants the ribbon at the point of transition away from pure elastic ?

    This is a good point.  The amount of hair does not mean a hill of beans if the rehair is not good.  A well rehaired bow should have a feeling of solidity as one plays....engaging the elasticity of more hair as the player “pushes” the bow.  If the hair does not have this linear resistance the bow feels mushy even if the appropriate amount of hair is used.....as analogy....it would be like having a discussion about the width of a soundpost without being able to make it fit.

     

  15. 2 hours ago, Lindsayb said:

    I have a Scherl and Roth 3/4 violin I am working on for a local youth program (charity) and am wondering if it is possible to replace a single Caspari-style peg (E string) instead of rebushing the whole peg box to return it to friction pegs. The E string caspari-style peg runs out of thread at an Eb and wont hold with fine tuner adjustments either. All the other pegs are working fine (despite being Caspari!)

    Any advice would be welcome as I'd like to get this instrument back into a student's hands quickly and cheaply.

    Actually, now that I think of it, I thing you will find the Caspari bushing has come unglued.  Remove the peg, and you will see a fiber bushing where the 2 sides of the peg were contacting.  Reglue that bushing and you may be okay.

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