saddle location

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Kevin Manuele
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saddle location

Post by Kevin Manuele » Fri Oct 25, 2019 2:40 pm

In both editions, the example calculation (section 20.3.2) for routing the steel string saddle slot gives a dimension from (compensated) nut to front edge of the saddle, but using the active string length values from table 21-2. These values are from contact point to contact point.

This would seem to provide no margin for adjustment for the shortest string.

I would expect the saddle to be located so the range of compensation (about 3 mm) to be centered on the saddle width (say, 5 mm).

What am I missing?

Thanks

Kevin

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Trevor Gore
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Re: saddle location

Post by Trevor Gore » Fri Oct 25, 2019 4:01 pm

Kevin Manuele wrote:
Fri Oct 25, 2019 2:40 pm
What am I missing?
...that I say in the last two lines of para 2 Section 20.3.2 (both editions) that you work it out for the string that has the shortest distance (typically the first string). The longest distance is typically ~ 3mm more, so that gives you ~2mm "land" of saddle on a 5mm saddle for that string, which is a sensible minimum. If the first string break point was on the middle of the saddle, the 6th string break point would be off the back edge. That's with a non-slanted saddle and nut compensation. This is one of the reasons why I rout the saddle slot after gluing the bridge on - the tolerances are quite tight, so the saddle slot has to be in the right place.

If you want to slant the saddle you could use a narrower one, but you'd have to figure the slant angle and saddle thickness that made sure all the strings were appropriately compensated and still landed on the saddle, whatever the brand/type of strings that were being used.

Kevin Manuele
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Re: saddle location

Post by Kevin Manuele » Sat Oct 26, 2019 6:01 am

Thanks;

Though I was not suggesting that the first string be centered, but that the range be centered.

Using string compensations from Table 21-2, and a fixed nut compensation of 1.1 mm, the first string would be at 645.3 mm and sixth at 647.9 mm (measured from the nut) from the equation in Section 20.3.2, for a range of 2.6 mm.

If we center this range on a 5 mm straight saddle, the first and sixth strings are 1.2 mm from the front and back of saddle respectively.

So I would put the front edge at 643.8, not at 645.3 -- which is what I assumed the text was suggesting.

Are my assumptions (and arithmetic) correct ?

Agree that these tolerances are tight, and difficult to measure over these distances.

Thanks again

Kevin

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Trevor Gore
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Re: saddle location

Post by Trevor Gore » Sat Oct 26, 2019 10:09 am

The problem I find is that leaving only1.2mm on the back of the saddle, 6th string, tends to lead to too much crushing and wear on the saddle, especially if Tusq is used. Obviously this is also a problem when using the traditional narrow saddle. As the contact point only ever moves forward as the bridge rotates over time, I like to leave as much material there as I can.

Kevin Manuele
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Joined: Tue Sep 18, 2018 4:38 am

Re: saddle location

Post by Kevin Manuele » Sun Oct 27, 2019 4:28 am

re: 6th string bearing surface. Something my novice brain did not consider :-(

Thanks for your input and time.

Kevin

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