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scordatura

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Posts posted by scordatura

  1. 1 hour ago, Don Noon said:

    I looked very carefully under glancing light at the parts that were milled from the model, and I could see no evidence of ripple from the model.  Either it's just a rendering artifact, or something else that doesn't matter.  I only care about the wood things.

    I kind of like the corduroy effect of your milling. Reminds me of the pants I used to wear back in the day!

  2. 13 minutes ago, JohnCockburn said:

    Is this done from a 3-D scan of the original, or constructed somehow from photos?

    Sorry if this is a silly question. I know very little about this technology.

    Scan. Photos are possible but difficult to get this level of accuracy.

  3. 5 minutes ago, HoGo said:

    Sure it is... in that "toxic green" color :-)

    I know that the green color is not my first choice. For the next one I want to do red, brown or orange. The only problem is I am trying to stay low maintenance with my friend who is using his expensive 3D printer to render my parts. That green is what was loaded in the machine. So far it is free. I want to keep it that way if I can. It took 6.5 hours to print. After all I could use some spray paint to make it more "real". ;)

  4. 9 minutes ago, Three13 said:

    Filius Andreae scrolls show up on Del Gesus after his retirement and recoevry around 1732, and last until 1740. I think this is the 1741 Kreisler, not the 1733. Did you make this? It's wonderful.

    It is the 1730 or 1733 or whatever date the one at the LOC is. So a 1732 date it could be filius. Roger Hargrave in his article on the Kreisler however does not mention filius in his description of the scroll. I am not aware of another GDG that has Kreisler's name associated with it.

    I did make it or in reality the 3D printer made it from an STL mesh file. So it is a plastic reincarnation of good old Giuseppe. A bit strange isn't it?

  5. 1 hour ago, MANFIO said:

    I think that casts of scroll and plates of good instruments could be commercially available. I remember Bissolotti had a plaster cast of a Strad scroll in his bench.

    I totally agree with this. Having a 3d model to assist your carving is a great help vs. pictures.

  6. On 1/19/2020 at 7:44 PM, Michael_Molnar said:

    After a long hiatus, I fired up the CNC after making a lot of repairs. Like me, the machine is showing its age. However, we are still functioning. These photos show the plate shape and hold-down tabs which are sawn off after the top surface is done.  The next process is to do the surface contour tomorrow.

    A71B2375-0D9C-44FC-9DD7-5C93C85E8291.thumb.jpeg.193e370eba6a2e3648e12c9d1f7cebb8.jpeg
     

    It is hard to tell from the pic but is that a straight flute bit to cut the outline? From the fuzz on the top edge it almost looks like an up cut mill at work.

  7. 20 hours ago, Steven P said:

    I am new to this forum/discussion. But I have made violin parts and many other things by CNC for nearly a decade. As stated earlier, CNC is a labor saving device and can't effectively be used to finalize a violin plate unless the entire instrument is machine produced, in which case you will get what you deserve. We would not use dull tools or those with inferior steel (for example) just because some ancients did. Modern tech like CNC makes the work easier and more approachable by many. My shop is presently in storage due to a move so I have been focused on design for CNC. This link is to stl files for the top and back plates I recently constructed and cleaned up: My STL files . The original design was in Rhino using classical drawings and contours available everywhere. They may have also been smoothed in Aspire. As for arching, there is much nonsense on the web about it, especially around curtate cycloids. You can read the article at the link for my take on arching, or go to the source here . In brief, arching comes from contours. My stl files are nowhere near final - they are meant to save labor and then be finished by hand, so perhaps they should have a generous Z cutting margin. I have made tool paths for these plates in Aspire, and there can be interesting challenges in constructing the paths and executing them. I have not cut these exact versions so I don't know the thicknesses that will result. My normal workflow would prevent this from being a problem, but yours may not. Care is needed!

    From a quick glance it looks like your design is Strad inspired. Is it a particular instrument (Messiah) P or PG mould? I have found it pays to be picky with your pattern source files rather going down the wrong path. Strad posters?

    Also interested why you chose Aspire for smoothing and tool paths.

  8. I can't speak for all of the makers that are pursuing CNC efforts, but reproducing arching distortions is in my opinion absurd and not worth discussing. I think that even though it has been stated before that CNC is used to do somewhat rough work or making of moulds, etc., many people responding to this thread are missing the point and expressing their opinions. That is all well and good but it is adding unnecessary opinion based content to this thread. Please use these threads to promote or criticize CNC in violin making:

     

     

  9. After spending a lot of time trying to flatten my Craftsman #7 I am ready to take the plunge with a "try" or #7 purchase.

    Wood River $350

    Lie Nielsen $425

    Quangcheng on sale for $277 at workshopheaven.com 

    Tried to order from workshopheaven and cannot purchase in the US. Apparently the Wood River is a rebranded Quangcheng.  Ordered from Woodcraft.com at $348 shipped with tax after a 10% code. Hopefullly this will not require a lot of setup...

  10. 1 hour ago, Urban Luthier said:

    It is near impossible for amateurs to get a hold of plaster casts for study purposes

    Yes. I am envious when I see casts of important instruments. I remember seeing a cast at the LOC for arching corrections and/or sound post patch that Rene Morel made. I thought how much I would like to make a positive mold of that!

  11. 6 hours ago, Urban Luthier said:

    Trouble with 3d printing from CT scans (CT->STL) is the accuracy of the resin print. S&Z ran into issues with this with the Tuscan Strad publication. They simply couldn't get the accuracy they were looking for + - .3mm was considered too great a margin of error. 

    Who is S&Z (Sam Z?) Could you elaborate more on the Tuscan Strad pub you are referring to?

  12. 16 hours ago, BenPearce said:

    Hi Scordatura, that's a pretty broad question, but everything from Creo and 3DSMAx to Illustrator and end/ballmills ranging from 0.008" to 2.000"in diameter.

    Are you using CNC to make violins or for other uses?

  13. 1 hour ago, NCLuthierWyatt said:

    As an alternative to using CNC machinery have any of you seen the wood router offered by Gemini? Looks like a great option for those wishing to avoid the high initial investment of laser scanning along with having a lot less to go wrong. I work with lots of laser scanning and high end 3D printing in a dental laboratory along with some experience with CNC machinery in producing custom components for cars. Feel free to pick my brain if anyone needs help with figuring out how to export and edit STL files. 

    Here's a demo of it. Not too bad for $3200. 

    I thought about going that route. I even bought plans to create your own duplicating router but never went farther when CNC got less expensive. 

    As far as scanning laser or a probe to get the .svg file, I would think that some makers would just design it in software from plans. At one point I thought that I might do some plates in a wood like basswood (easy to carve) and then use a probe on a CNC to generate the "mesh" rather than design in the Fusion 360 software. I looked into laser scanning but found it too expensive. In addition if you are going from an older instrument you have to correct for arching distortion and other asymmetries. While not impossible it involves decisions and knowledge how string pressure and sound post distortion affects arching. 

    The medical community uses software to go from CT scans to stl files. https://www.embodi3d.com/blogs/entry/345-a-ridiculously-easy-way-to-convert-ct-scans-to-3d-printable-bone-stl-models-for-free-in-minutes/. The problem is getting a CT scan file. I think that the Library of Congress used to have CT scan files but they have disappeared from the interwebs. I tried to contact the curator at the LOC regarding this but got...crickets. Aren't the instruments and assets there the property of the "people"? Oh well. Ct scan files are also VERY large!

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