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I posted a question about two weeks ago and have not seen it nor received any response from moderator as to status of account.

Am I on the air?

Looks like the moderator delay is still enforced so I will try to get an answer at the same time.

The bridge has a published radius of 41mm.  It appears that the top of the finger board has the same radius.

The spacing from fingerboard to string notch is given  for G and E strings.

If we knew the numbers for the other two strings, could we not just adjust the notches to match these numbers and avoid removing the bridge or doing it later to clean it up

Thanks,

 

Jack Schmidling

Marengo il.

 

 

 

 

 

 

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1 hour ago, JackSchmidling said:

...If we knew the numbers for the other two strings, could we not just adjust the notches to match these numbers [?]...

I’m trying to think of some reason it can’t be done this way, and I’m not coming up anything.

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The reason why the G and E heights of the strings above the fingerboard are given and not the D and A is that only two points are needed to establish the bridge curve. Once the heights for the G and E are laid out, the bridge template is positioned so it meets both points. The curve is then traced onto the bridge from the template. Then the exact spacing of the strings may be determined by using dividers.

As far as the standard for fingerboard radius, 42 or 41.5 are more common.

If the fingerboard is properly shaped and the bridge follows a good template, there shouldn’t be any serious issues with the heights of the middle strings.

One detail to consider is the diameter of the D or A string. If it’s thinner (like a steel core A or silver D) the string groove will need to be shallower to correspond.

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  • Shelbow changed the title to Bridge questions

Let me try a different approach.

I have a violin that bumps the wrong strings too frequently.  As it could not possibly be me ha ha, I suspect a possible problem with the bridge.

I check the string height at G and E and they are nominal.

If I had the other numbers, I would know if the bridge was the problem but nowhere on Earth can I find those other numbers.

I presume a female version of the template should fit on top of the strings but there are other issues with this approach.

Jack

 

 

 

 

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1 hour ago, FiddleDoug said:

A good luthier who knows what he/she is doing could fix that right up for you without guessing what might or might not work.

Yup.

FWIW, sounds like the curve on your bridge is flat. The only thing to do is make a new bridge. Wood is super easy to remove, a little more difficult to put back on.

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2 minutes ago, arglebargle said:

Yup.

FWIW, sounds like the curve on your bridge is flat. The only thing to do is make a new bridge. Wood is super easy to remove, a little more difficult to put back on.

you don't have to make a new bridge if the strings are high enough, you can go as low as 3mm on the e and 4.5mm on the G and that might give you enough room to get the correct curve without fitting a new bridge, of course if the strings are already that low you will need a new bridge.

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53 minutes ago, Strad O Various Jr. said:

you don't have to make a new bridge if the strings are high enough, you can go as low as 3mm on the e and 4.5mm on the G and that might give you enough room to get the correct curve without fitting a new bridge, of course if the strings are already that low you will need a new bridge.

Thanks Captain Obvious!

An E at 3mm and a G at 4.5 would be a failed bridge in my book.

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9 minutes ago, arglebargle said:

Thanks Captain Obvious!

An E at 3mm and a G at 4.5 would be a failed bridge in my book.

Maybe if you're a professional and you're trying to set up the violin optimally, but for an amateur just trying to get the violin to work, it would be fine. Weisshaar actually says 4.7mm for the G as optimal and tonnes of people set up the e at 3mm, not me, but that's not outrageous to do.

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1 hour ago, arglebargle said:

Wood is super easy to remove, a little more difficult to put back on.

The first rule of being a King is to remember,” you can’t say ‘on with his head,’ after you’ve said,‘off with his head!’”

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14 hours ago, Strad O Various Jr. said:

You can't properly fit a bridge without having a 42mm curve template to fit on top of the strings...

I start with that template, but lower the G slightly to give more G/D bow clearance (but still working with the E and G height measurements off the fingerboard).

10 hours ago, arglebargle said:

An E at 3mm and a G at 4.5 would be a failed bridge in my book.

Fingerboard scoop makes a huge difference in what end-of-fingerboard clearances work or not, and what works for a professional soloist violinist is vastly different from what works for a fiddle player.  3 and 4.5 mm clearance E/G look ideal for a fiddle.

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18 hours ago, JackSchmidling said:

The spacing from fingerboard to string notch is given  for G and E strings.

If we knew the numbers for the other two strings, could we not just adjust the notches to match these numbers and avoid removing the bridge or doing it later to clean it up

This is the way I work, with the strings installed and the bridge still rough (apart from the feet) I first do the height of the G and the E strings and then the heights of the D and A, then I disassemble the bridge and finish it .
But I do this by looking at the radius above the strings at the bridge, the distance of the D and A strings from the fingerboard is just a consequence, and it couldn't be otherwise. The right match between the radius used at the bridge and the radius at the end of the fingerboard should give a comfortable string distance (action), which for me should be progressive from G to E depending on the type of strings used. For example I like G 5.5 D 5.3 A 4.5 E 3.8/3.5 or also G&D 5.5 A 4.5 E 3.8/3.5 mm

In any case, if you know the radius above the strings, the diameter of your strings, and the radius at the end of your fingerboard you can do a simple drawing and get all the measurements you need in an accurate way.

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Are y'all measuring to the middle of the string or to the bottom?

I make mine 5 for G and 3.3 (give or take) for the E. Both measured to the bottom. 

I think that some professional players like the strings a little higher for more tactile feedback, perhaps. Closer to 5.5-3.5/7. 

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20 minutes ago, Nick Allen said:

Are y'all measuring to the middle of the string or to the bottom?

I make mine 5 for G and 3.3 (give or take) for the E. Both measured to the bottom. 

I think that some professional players like the strings a little higher for more tactile feedback, perhaps. Closer to 5.5-3.5/7. 

Measuring to the bottom. Measuring to the middle is less practical because it isn’t really a measurement of clearance, as a string is stopped by pressing its bottom surface against the fingerboard. 

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What's with the limit on postings per day?
Pretty strange.

I need to clarify a few things to save a lot of typing and bandwidth.

First of all, DIY is in my genes. If I can do something and it's fun, I will do it. I will go to a specialist if I can't or don't want to do it.

My immediate wish was to come up with a way to check a bridge on an existing violin and see how it compares to a standard without having to remove it and possibly fix it if not right, again in situ.

I think Mr. Sora came close to answering my questions but leaves me with a few more.

It is very easy to measure the top of string to fingerboard with great precision with the depth gauge of a dial caliper. All other standard methods are very crude by comparison.

There are many reasons not to measure from the bottom and string diameters being just one. My current strings are Fiddlerman synthetic and the G string is much smaller than most other strings and is actually smaller than the D string.

The good news is that the bow plays on the top of the strings so who cares where the center or bottom is?

Unless I am missing something serious here, those four numbers are all we need to know to check or make a bridge from scratch.

You cut the notches one string at a time in situ just pushing that string out of the way to cut it. I used a diamond cutting wheel from a Dremmel as a hand tool or sort of file.

When all done it looks like the photo below. I didn't get rid of the extra wood yet but a belt sander and a smooth file would do the trick and again no need to think about the curve or it's radius.

Another question is, what harm does leaving the excessive wood do?

This violin was purchased new about 50 years ago and as Lewis has a good reputation for decent student violins it is curious that the logo and square side is facing the fingerboard but the curve drops on the E side as normal.

It is also strange that height of the strings was so much higher than usual.

Nuff for now,

Jack




 

 

 

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2 hours ago, JackSchmidling said:

...My immediate wish was to come up with a way to check a bridge on an existing violin and see how it compares to a standard without having to remove it and possibly fix it if not right, again in situ...

The way to fix an existing bridge is to deepen some or all of the string grooves.  Once you've done this, there will be extra wood at the top of the bridge to remove.  The top should be cut lower, thinned and nicely rounded off.  I don't see how all of this could be done with the bridge "in situ."

 

2 hours ago, JackSchmidling said:

...what harm does leaving the excessive wood do?...

The weight of the excessive wood acts like a mute.  When you put a mute on a bridge it acts by adding weight to the top of the bridge.

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4 hours ago, JackSchmidling said:

There are many reasons not to measure from the bottom and string diameters being just one. My current strings are Fiddlerman synthetic and the G string is much smaller than most other strings and is actually smaller than the D string.

The good news is that the bow plays on the top of the strings so who cares where the center or bottom is?

String height is about the distance from fingerboard to string, or the amount of clearance a string has at rest. The middle and top of the string are not relevant because they aren’t the surfaces that come into contact with the fingerboard. You’re right that string diameter matters, and that’s exactly why using the middle or top of the string isn’t practical.

To fine tune the curvature of the bridge, a template can be placed over the strings to be sure that they’re all in good positions relative to each other for bow clearance, but that’s a separate thing, not a measurement of string height. 

4 hours ago, JackSchmidling said:
Unless I am missing something serious here, those four numbers are all we need to know to check or make a bridge from scratch.

You’re missing a lot of crucial information. String height is only one part of what determines how a bridge is cut. There are many more important measurements. 

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9 hours ago, JackSchmidling said:

This violin was purchased new about 50 years ago and as Lewis has a good reputation for decent student violins it is curious that the logo and square side is facing the fingerboard but the curve drops on the E side as normal.

It is also strange that height of the strings was so much higher than usual.

If this bridge has been on all those years, it sounds like it has warped. This would account for the face side becoming straighter than it originally was.

High string heights could indicate the neck elevation has changed over time. If you use a steel ruler laid on the fingerboard, projecting to the bridge, measure the distance. It should be 27mm, give or take 0.5mm.

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You can't fit string heights by measuring from the fingerboard because you don't know perfectly what the curve of the fingerboard is and string heights are set from the curve presented presented by the top of the strings, not the bottom, you need to make a 42mm radius curve template, and you set the d string ever so slightly higher than the curve, or you can, as I do have your template 42mm radius filed away slightly under the d string position to set it higher, Since you say your strings are on the high side, you should have no trouble adjusting to get the correct string height and curve, than you are going to have to take the bridge off and file the top surface so the grooves are only half the diameter of the string deep,

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3 hours ago, Strad O Various Jr. said:

You can't fit string heights by measuring from the fingerboard because you don't know perfectly what the curve of the fingerboard is 

Sharpen a new pencil, remove the eraser/brass and sand pencil evenly lengthwise just until you see the lead showing itself.

With the strings out of the way glide the half pencil across the fingerboard to enable a drawn line on a bridge blank, new or used.

Now one can use prescribed by others string heights or you can just use E and G recommended heights and connect their points using a template or your own scribed arc - be careful with the D string height and possibly the A.

After doing so, then come back and say one can't measure/fit string heights from the fingerboard. 

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