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Don Noon

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Wow... that was almost 6 years ago.  While there are still some after-effects from the surgery, it's not much compared to the accumulated fractures and sprains from decades of abuse.  Hopefully I can still get another decade or two of abuse out of the old wrists, and as of now they are still functional for what I want to do, which includes windsurfing and bowling, in addition to violinmaking.  Volleyball is ancient history... and the cause of the fractures and sprains.

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Based on Annelle Gregory’s spectacular Scheherazade recording posted by Don on June 3, I ordered her recent CD, which arrived this morning.  I listened to it on my home theater’s high-end audio system —  I’ve never heard a better sounding violin.  The unfamiliar Taneyev piece was 45 minutes long; the Rimsky-Korsakov was 15+ minutes.  

The written insert contained a short bio on Annelle.  She’s an award-winning, globe-trotting violin rock star, graduating first in her class, summa cum laude, from USC Thornton School of Music!  Since she could be using just about any violin that appealed to her means Don’s waiting list is only going to grow.

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15 hours ago, Don Noon said:

Chris... thanks for all that.  Where should I send your payoff? :)

You do realize a long waiting list could be a curse for someone who's supposed to be enjoying his retirement? :unsure:

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This thread has been pretty dormant for a few months, due in large part to the steep curve getting the CNC designs and tooling going.  The last few weeks have been pretty active, due in large part to kids being away to college and wife being out of the country and the VCR/receiver dying... and me being too old and boring to do anything more exciting than spend more time in the shop.

So I got two things done:  violin #27 I took off the top again to get a little more roundness to the low end (and stripped/revarnished it while I was at it). 

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And here's the test drive... 

The second item was violin #30, the first of my new designs and partially assisted by CNC for the purfling groove, plate outline, forms, and cutting some indexing features on the plates to assist carving (rough channel, long arch definition).  Still mostly hand work.

This is my "small" version, nominally 352mm back length, although it looks like it's closer to 351.  The client wanted small and light... and without the chinrest, it came in at 367 grams, which is about as light as I'd want to go.

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And the usual test drive... doesn't appear to be hurting for power, and will probably improve the high end with age (strung up for 4 days at this point).

If you quote this post, PLEASE edit out the photos and videos so we don't have to wear out our scroll wheels.

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I mostly use a scraper to get off most of it, and acetone for the remainder.  It takes a while, but there's less chemistry to worry about.

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After figuring out (con)Fusion360's file arrangements, I finally got some 3D modelling done.  This is just the center area of a viola back plate, not including the figure-8 low point of the plate, which I do separately.  There are some artifacts in the rendering, which don't show up in fabrication.

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And here is the first back plate off the machine.  There is a centerline arch groove which I milled previously... then I changed the arching design for the 3D work, so I'll fudge it in the fingerplane and scraping stages.  This is all I really want to get done on CNC:  get off most of the wood, get the geometry established without messing around with templates, and get the outline and purfling groove done.  I don't mind getting off the last mm or two by hand, and even WANT to have that hand-finished final result.IMG_2085.JPG.fc819a2b4118f1e7fc0cc469f7d0662c.JPG

Now I have to figure out how I want to do the hollowing.  For sure this first set will be the old way (by hand) until I settle on the concept and make the tooling.  At the moment, I'm thinking I should hollow out the inside first.

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12 minutes ago, Don Noon said:

  For sure this first set will be the old way (by hand) until I settle on the concept and make the tooling.  At the moment, I'm thinking I should hollow out the inside first.

What's wrong with figuring out the tooling and concept now?  It doesn't seem to me it took very long time wise to get this far.  We're all watching and impressed so far.

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Did you use loft to fill in the areas that were not defined by the arching contours? I am looking onto using Rhino because it has a “curve network” command that can from what I understand accomplish the skinning process better that Fusion 360. Hope this makes sense.

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3 hours ago, scordatura said:

Did you use loft to fill in the areas that were not defined by the arching contours? 

Yes... but the upper and lower bouts required a lot of thought to make profiles at an angle that would blend properly with the long and cross arches.

I can't answer whether any other program is better, as this is the only one I have ever used to try to do these complex compound curves.  I know there are 2 videos on YouTube showing how to make plate models in Fusion360 with the sculpting function, but I gave up on that method after a short time.  Seems totally wrong to my way of thought and what I want to accomplish.

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From looking at the body you posted above you can refine it by using smooth and combine functions. Sometimes you have to repeat it more than once. If that goes the wrong way you can of course undo. It is a bit of a strange dance...

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2 hours ago, scordatura said:

From looking at the body you posted above you can refine it by using smooth and combine functions. Sometimes you have to repeat it more than once. If that goes the wrong way you can of course undo. It is a bit of a strange dance...

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.

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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!

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7 hours 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.

Nice work Don! BTW I like the pyramids in the corners, they look cool (remind me of the pyramid bridges on guitars). How long did it take to cut the back as shown?

The artifacts in the model are where there is no surface curvature or tangency continuity between the partial surfaces. Especially where the tips of the triangles meet even with curvature continuity it is almost impossible to keep that perfectly smooth as the width of the surface decreases to zero and all the smoothness is managed at microscopical level. It is better to create such surfaces using one contonuous "half circle" sweep through the crossections that will be connected smoothly to the rest. Perhaps leaving small window in the center of the half circle that can be filled easier smoothly with the surrounding surfaces. Of course the rendered model magnifies these effects in real CNC cut they will be completely negligible. Even some tiny "holes" in seams of the model can be ignored for machining as the tool will just jump over them (or the CAM will fill them). Of course if you want to do computer animation with the model the artifacts will be unsighty and need to be smoothed out.

BTW, I believe Fusion has equivalents of the Rhino surface creation tools. They will be named differently or work a bit differently but I bet they are there, Rhino is not such special piece of SW.

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Fusion 360 only has loft. Rhino has curve network. This video illustrates what I am talking about. We should probably move this to the CNC discussion so we do not clog Don's bench thread.

 

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