Jump to content
Maestronet Forums

Shaping the corners outline.


Il Virtuoso
 Share

Recommended Posts

1 minute ago, Nestorvass said:

I agree with you better have a less uniform overhang than an ugly looking corner with uniform overhang. What do you think of the correction I made? Does it look any better in your opinion?

It's hard to say, because the shape of the corners also changes in the 2nd picture (more rounded)

Link to comment
Share on other sites

  • Replies 87
  • Created
  • Last Reply

Top Posters In This Topic

N,

While Michael Darnton is correct that you should strive to think out things in advance and follow correct procedures even on your first instrument it would be a sad thing if your first instrument was the best you ever make.

The upper corners are too long because you left a few tenths of a mm. extra wood when shaping your blocks. You can improve the look of this violin by shortening the overhang of the upper corners over the rib ends (without changing the angle!). This is easy to do and a slight difference in the overhang will not be as noticable as a difference in the length and shape of the corners and purfling.

It is important to keep in mind that a nicely shaped corner can be a thing of beauty while a perfect over hang.... not so much. If you make each instrument look and sound as well as possible and learn to analyze and learn from your mistakes your next instruments will improve over time.

Link to comment
Share on other sites

2 minutes ago, David Burgess said:

You can still trim the length of the rib corners. The joint will start to show in the chamfer as you cut it back, but then you can trim the thickness of the C-bout portion of the rib to bring the joint back where you want it.

You just have to stop before you hit willow/spruce :D

Link to comment
Share on other sites

11 minutes ago, David Burgess said:

You can still trim the length of the rib corners. The joint will start to show in the chamfer as you cut it back, but then you can trim the thickness of the C-bout portion of the rib to bring the joint back where you want it, and bring the width of the chamfer back were it was.

And how will i trim the c bout rib then? With a square scraper I guess?

Link to comment
Share on other sites

2 minutes ago, David Burgess said:

You can still trim the length of the rib corners. The joint will start to show in the chamfer as you cut it back, but then you can trim the thickness of the C-bout portion of the rib to bring the joint back where you want it, and bring the width of the chamfer back were it was.

That too. Small amounts of wood make big differences in how things look. By shortening and thinning the rib ends and then skimping on the over hang you can still make these corners look very nice. 

Link to comment
Share on other sites

12 minutes ago, Bodacious Cowboy said:

It's hard to say, because the shape of the corners also changes in the 2nd picture (more rounded)

I only changed the upper left one. The other three are just the outine of the ribs using a 2.5mm washer for the overhang. Sorry what I should have said is does the upper left corner look better than the one I did before? :lol:

Link to comment
Share on other sites

3 minutes ago, Nestorvass said:

I only changed the upper left one. The other three are just the outine of the ribs using a 2.5mm washer for the overhang. Sorry what I should have said is does the upper left corner look better than the one I did before? :lol:

Ah, OK. Yes, it looks better.

Link to comment
Share on other sites

Just now, nathan slobodkin said:

That too. Small amounts of wood make big differences in how things look. By shortening and thinning the rib ends and then skimping on the over hang you can still make these corners look very nice. 

Honestly due to lack of experience I didn't think that trimming the ribs even half a mm less would have such a huge impact in the shape of the corner. That's the problem when making a first violin, or at least what I experience. I don't know what impact will a specific step in the making process have in after 10 steps. I do have an idea of how a violin is built from start to finish but these small details that alter the final shape, I do not know. The only good that comes out of it is that after I finish this violin I will know first hand how a specific step in the making process impacts the following steps and any mistakes I might do now, I will (hopefully ) not repeat them in the second one :)

Link to comment
Share on other sites

Just now, Bodacious Cowboy said:

Ah, OK. Yes, it looks better.

Thank you for letting me know. I couldn't believe that half a mm less overhang would have such a huge difference in the apperance of the corner. Well now I know haha.  Thankfully I still have a bit of material to make corrections either by altering the overhang or by trimming the ribs and then feather their edge again as Mr. @David Burgess suggested

Link to comment
Share on other sites

1 minute ago, nathan slobodkin said:

Safest for  a beginner would be to file the length back then file the ribs slightly thinner and lightly scrape the ribs without rounding the end over.

I suppose I should use a semi agressive half round file for it, followed by a super smooth crossing file and then scraper?

Link to comment
Share on other sites

Hi Nestor,

I've made corners in many different ways...but I always keep coming back to using a simple template (ala cornflake packet).  I use a small piece of clear material and make them about like this:

316663357_cornertemps.jpg.1708eaccfbc7060775d3de40ee802862.jpg

You can trace them off a good image/poster, or an instrument.

To use them, I like to mark lightly on the plate where the ribs point is, then erase the pencil off-set line near the corner...then just use the template to come up with something satisfactory.  Basically, it's taking a good corner shape, and making it work into your margins & rib shape.  If there's anything irregular about the rib structure (or if you're worried making a P model on a PG mold) it becomes a slight change in overhang, rather than corner shape.

When cutting the final plate outline, I like to check the corner shape by lightly using a purfling marker (can use lightly on the underside) to see if the miters end nicely (which is something that naturally happens on nice corners.)

Speaking of the computer images you're doing....try off-setting the outline by the measurement of purfling offset you plan to use (usually a bit over 4mm) and see how that looks.  It can help visualizing corners by seeing what purfling shape they make and comparing the whole ensemble to reference photos.

Link to comment
Share on other sites

7 hours ago, Nestorvass said:

Yes ofcourse, I should not that I am not making an exact copy of the titian. I mainly bought the poster for the titian because I had built the pform and I wanted a violin which was built on this form and sounded great. So the only think I am aiming to copy from the Titian is probably just the arching and the thickness of both the plates. Here's a photo of the ribs

I think a good example of violin made on the P form with long corners is the Betts 1704 (probably the one with the longest Stradivari's corners ever). It might be worth checking them out and seeing how they fit on your rib corners before shortening them.

843893544_3-bettspunte.thumb.jpg.db6bc6a17c34586986c6d391df805ddd.jpg2031092969_5-bettspuntefasce.thumb.jpg.7de2341af0205debbf3e8118ea0dac6b.jpg

 

In your ribs you have hollowed too much the curves of the blocks (red arrows on the photo), a fairly typical mistake in the first violins (at least it was for me:)), next time keep them more flat. Even the original Stradivari P form corner templates are too curved, probably he did not remove the mark in the central part of the blocks, because if you look at the Ct scans of the original ribs they look flatter. A good way to keep under control the corners length  is to measure the distance from tip to tip (red lines on the photo) and compare it with that of the CT scan. In any case, if you keep the current distance of your tips, next time you will have a reference as a basis for shortening measures.

458687522_Pnestor.jpg.f5c8ed489ff1d0afdee5fdf871e5e389.jpg

Link to comment
Share on other sites

29 minutes ago, Davide Sora said:

I think a good example of violin made on the P form with long corners is the Betts 1704 (probably the one with the longest Stradivari's corners ever). It might be worth checking them out and seeing how they fit on your rib corners before shortening them.

 

Thank you for the suggestion Mr. Sora, I had no idea that Stradivari had made an instrument with such long corners. I will scale it on cad if I find any reliable pictures print it and see how it fits my instrument. For now the design that I came up with is in the picture below. Its the result of shortening  the upper corners edge overhang about .5 mm. I posted a picture before having corrected only the upper left corner but now I corrected all of them and here's a picture of the result. I would really like to know your opinion about it :) Either way I am not going to proceed before checking the Betts as you suggested. Having a Stradivari violin with long corners and made on the P form is the best reference i could ask for.

 

Personal Violn Corners construction v11.png

Link to comment
Share on other sites

55 minutes ago, Davide Sora said:

In your ribs you have hollowed too much the curves of the blocks (red arrows on the photo), a fairly typical mistake in the first violins (at least it was for me:)), next time keep them more flat. Even the original Stradivari P form corner templates are too curved, probably he did not remove the mark in the central part of the blocks, because if you look at the Ct scans of the original ribs they look flatter. A good way to keep under control the corners length  is to measure the distance from tip to tip (red lines on the photo) and compare it with that of the CT scan. In any case, if you keep the current distance of your tips, next time you will have a reference as a basis for shortening measures.

 

I am sorry Mr. Sora I must have missed the second part of your reply. I didn't know that Stradivari made his blocks flatter than the templates of his mould. I assumed it would be the same so thats what I did like you explained in your videos, to take off the pencil line with knife and remove the middle part with the gouge and check with the square. Though I assume that your corner blocks templates have this "correction" in their shape. Meaning that they are flatter. I will keep that in mind for my second violin I had no idea, thank you :) Is this the case for all stradivari moulds and their corresponding corner block templates or just the P form?

Link to comment
Share on other sites

31 minutes ago, Nestorvass said:

Thank you for the suggestion Mr. Sora, I had no idea that Stradivari had made an instrument with such long corners. I will scale it on cad if I find any reliable pictures print it and see how it fits my instrument. For now the design that I came up with is in the picture below. Its the result of shortening  the upper corners edge overhang about .5 mm. I posted a picture before having corrected only the upper left corner but now I corrected all of them and here's a picture of the result. I would really like to know your opinion about it :) Either way I am not going to proceed before checking the Betts as you suggested. Having a Stradivari violin with long corners and made on the P form is the best reference i could ask for.

 

Personal Violn Corners construction v11.png

They still seem a bit long to me, but I think it depends more on the visual effect caused by the external curves that are too deep and with the deepest point of the curve moved too high (especially in the upper tip) than on their actual length, because evaluating the depth of the complete C looks like it might be fine. The right C is better than the left, the lower left corner is the worst.:)

Link to comment
Share on other sites

4 minutes ago, Davide Sora said:

They still seem a bit long to me, but I think it depends more on the visual effect caused by the external curves that are too deep and with the deepest point of the curve moved too high (especially in the upper tip) than on their actual length, because evaluating the depth of the complete C looks like it might be fine. The right C is better than the left, the lower left corner is the worst.:)

Thank you,  Mr. Sora for telling me what you think of it. I might shorten them even further but then the overhang of the edge of the corner from the ribs will become around 1.8 mm (if i dont make the edge of the ribs shorter). Would you mind telling me what is wrong with the lower left corner, so that i can hopefully fix it? Does it have too much of a hook into the cbouts area? 

Link to comment
Share on other sites

10 minutes ago, David Burgess said:

I agree with Davide S., that the radii on the outside of your corner blocks have somehow become to tight..

I don't have enough information yet to suggest how or why that happened.

Yes I agree with you and Mr. Sora, I see that as well. I don't know how I managed to do that and I doubt I can fix it. Since I assume that would require to add wood . I will pay more attention to that when I make the second one. I guess I'll have to live with it though it does make me a little sad that I can't fix it. My guess is that i might have filled a bit more wood in the middle when making the corner block templates. I probably didn't pay enough attention and due to lack of experience I didn't know how much it would impact the rest of the instrument. Well seems like I learned to pay more attention the hard way...

Link to comment
Share on other sites

19 minutes ago, Nestorvass said:

I am sorry Mr. Sora I must have missed the second part of your reply. I didn't know that Stradivari made his blocks flatter than the templates of his mould. I assumed it would be the same so thats what I did like you explained in your videos, to take off the pencil line with knife and remove the middle part with the gouge and check with the square. Though I assume that your corner blocks templates have this "correction" in their shape. Meaning that they are flatter. I will keep that in mind for my second violin I had no idea, thank you :) Is this the case for all stradivari moulds and their corresponding corner block templates or just the P form?

I suppose you are referring to the photo of my P form on my site, because only the G form appears in my videos, which has the curves of the blocks flatter than the P. The original PG and G forms have flatter block templates, while the P ones are actually more curved, which is indeed a typical feature of this model. The templates of my form are copied from the originals because I thought it was interesting to understand how Stradivari using those templates arrived at the final shape of the corners that you see in violins, and my conclusion is that the templates were only used for roughing staying away from the marks, finishing the work only by eye making flatter curves.

Later I thought about making more accurate corner templates, but out of laziness I never made them:P. To justify myself then I thought: what the heck, if they were good for Stradivari and his workers, they could be good for me too! In fact, when you've figured out how to create curves, you don't really need templates, but it takes a lot of practice for that.

748373515_FormaP-DavideSorarid.thumb.jpg.a26545eec9c97e7481d7859c84c3445b.jpgMy P form

1637799923_P(1705)puntasup.thumb.jpg.54f33831b4a219d7ee5f8aaff84b0b90.jpg1770039788_P(1705)puntainf.thumb.jpg.b5feba6f2a5bda514ec0557d39515810.jpgP 1705

1386989498_P(B)Puntasup.thumb.jpg.0b6e6d30afbfa821478c2e5b543b5d89.jpg740652422_P(B)Puntainf.thumb.jpg.c56d3477006f14ffde05b69f7cea267d.jpgP/B

 

 

Link to comment
Share on other sites

42 minutes ago, Nestorvass said:

 Would you mind telling me what is wrong with the lower left corner, so that i can hopefully fix it? Does it have too much of a hook into the cbouts area? 

A bit too hooked in the C (arrow), the end of the curve on the other side is too straight (section indicated).

Punta.png.77cbc32e0fdcbe2ad8c46ca164f42aae.png

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.




×
×
  • Create New...