Official Luthiers Forum!

what advantages and disadvantages has a backangled (towards the pins) saddle compared to a not angled?
has anyone the possibility (computer programm for physics) thanks for your effortsto tell me something about the upcomming forces of the string tenson on both?
Thanks for your efforts!

I put about a 7 degree angle in my saddle slots instead of just a vertical slot. Not taking about the angle across the strings to account for compensation.

I'm not really sure if it makes much difference since I have never really done any kind of comparisons. It does divide the break in front of the saddle which may or may not help keep the bridge from splitting.

I have read people say that angling it back also allows the amount of compensation to diminish as the saddle height comes down and increase as you raise the saddle height but I'm not sure if that is just wishful thinking.

In the end, I decided to start doing it because it might help with structure a bit but it definitely doesn't make construction any more difficult so why not? I don't know for sure what the angle I use is since I made a little jig a long time ago. I also don't remember how I settled on that angle but I'm sure I had a reason.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

More pressure on the bottom of the slot and less on the front wall, which is good for UST pickups and reduces the chance of slot end cracks. It causes a small change in compensation when you raise/lower the saddle height, which can be a good thing since higher action needs more compensation.

The bridge rotates under tension, so a slot machined perfectly vertical is actually slightly forward-leaning. I machine it vertical into the bridge blank, and then taper the thickness from the underside which tilts the slot (and pin holes) back a few degrees.

I rout the saddle slot after the bridge is glued to the top. If I want to angle the slot back I put a shim under the front of the simple router jig I use. Compensation, like equal tempered tuning, is a compromise so I'm not so sure it makes much difference, but it might help keep the bridge in one piece.

More pressure on the bottom of the slot and less on the front wall, which is good for UST pickups and reduces the chance of slot end cracks.

Dear Dennis, I don´t think that is true. I think the angled saddle will much more tend to rotate forward-upward, so the downward pressure to the bottom of the slot will decrease, and that is the opposit of what an piezo-undersaddle-pickup needs. It will decrease the torc on the backside of the bridge so that it will not lift where it "normally" tend to lift.

Santa Cruz is one company that uses back angled saddles.
I angle them back about 2 degrees, which is close to the amount of bridge rotation under tension. The self compensating angle is much more than that (7 or 8 maybe?). I am conservative because through saddles that I use will look less traditional with that much back angle.

The only way to decrease the torque on the bridge is by reducing the string height over the top. The saddle design has no effect on this. However, you can reduce the lifting force on the backside of the bridge by making the bridge wider (front to back).

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John

So as the guitar ages and especially if the instrument has been built on the lighter side to be responsive the neck angle deteriorates and to compensate for the higher action that results and can persist for a decade or more if not addressed and subsequent set-ups will be milling the saddle downward. Neck resets can be needed anywhere from 5 years to 30 typically.

We often have to take a saddle down so low that only the crown of the saddle is proud of the slot. When there is no more crown a neck reset cannot be avoided.

String ramps depending on the instrument may be appropriate for the instrument if a neck reset is not an option or in the budget.

When a saddle is angled backwards depending on the degree of angle as we mill it down which should be considered a normal part of the guitar's adjustments as it ages the break point of the speaking length of the stings moves forward. The less the backward angle the less the speaking length of all of the strings is shortened.

This can and does cause intonation problems in time that are not unlike locating the saddle too far forward in the first place.

The less the backward angle the less this is a consideration.

Where the intonation problems do come into play if they are bothersome to the player what results is less time between neck reset time.

A compromise if you do back angle would be to do it only a few degrees minimizing the shortening of the speaking length of the strings.

Regarding a UST (under saddle transducer aka pick-up) a common malady of our gigging musicians is poor balance from their pick-up. More often than not the culprit is a saddle slot that is not flat and as such puts more pressure on the UST in some areas than others.

The remedy that is simple for us because we have a saddle mill is to mill the existing saddle slot dead flat and the balance problems often go away.

This can't be done easily if the slot is backwards leaning because the mill is attached to the guitar top or at least our's is. Sure it could be back angled as Clay suggested above but our's uses vacuum and is attached to the guitar top making it level with the guitar top.

So here are two examples of the serviceability of an instrument being compromised by a back angled saddle. Neither of these problems exist with a 90 degree saddle.

I'll add that some builders ship with two saddles a winter and a summer saddle. This is not only a good idea but it underscores the idea that saddle height needs to be adjusted even for seasonal changes at times. I have 8 of my original, prototype Heshtone Guitars in my living room. They live in RH of 42 - 48% year around with no exceptions except for power failures here that are common now sadly...

I find I have to use winter and summer saddles even on these 17 year old, seasoned instruments. If I had back angled my saddles to a larger degree like some mentioned here my intonation would change with the seasons and I'm not on board with that.

So with all this offered and explained there again, again is a reason why tradition brought us to how a traditional acoustic guitar is built as in Martin and others. I see value in some small about of back angle and the intonation issues would likely be so minimal with a 2 degree back angle that it would not be noticed. But the less the angle the less the benefit of the back angle in terms of downward pressure being optimized.

If you are new to building you have a thousand things to master just to build a conventionally designed acoustic guitar. If it were me I would get many of these things down before venturing into some of the stuff that you will read about here. I also understand the need to want to build a better mouse trap.

Juergen my friend serviceability is super important even though this is a builder forum and some may look down their noses at repair folks. Repair folks include some of the finest builders in the world. I was checking out on-line a TJ Thompson instrument the other day that has a price tag go $40K. He used to run the repair department at Elderly Instruments.

Dear Hesh.
I have the greatest respect for repair folks! I know you are the people that have to correct the mistakes the builder made, and a lot of "normal" repairs of issues that come out with lifetime of an instrument. And I know too that you often must be very creative to find a solution. And I know that the very good repair folks like you at Ann Arbor Guitars must have extrordinairy craftsman skills!
Thank you for your advice!

Juergen thanks very much for this I appreciate it greatly. This is my passion, guitars I spend nearly every waking moment thinking of them, fixing them, playing them and sadly.... buying them...

Had one additional thought during the drive home from work at the shop this morning.

When the neck angle starts to change, the reason for needing to mill the saddle down is the neck is slowly folding into the body as the guitar's shoulders collapse. Although in very small amounts this means the nut is moving toward the saddle.

The "speaking length" for those who do not know is the term that refers to a stringed instruments unencumbered part of the string after it leaves the nut slot and/or the saddle crown break point. On other instruments it's the clear, vibrating part of the string.

So with an angled saddle when we mill it down if the angle is very great we are shortening the speaking length of the strings. But the reason for this post is that we mill the saddle because the neck angle is deteriorating and that means that this change in neck angle is also shortening the speaking length of the strings.

What results is what people experience playing cowboy chords on an instrument that needs a neck reset, the intonation is off. You may not notice it in the cowboy chord first three positions but for those of us who play up the neck it can be dramatic and result in the instrument being unplayable.

In the repair business we observe neck angles on all guitars changing to some degree if only very slowly all of the time and over time the angle changes enough to require that neck reset on an acoustic and some electrics and shims on bolt - on electrics.

So I am speaking of what could be called a perfect storm a deteriorating neck angle requiring a shorter saddle until neck reset time but when we shorten the saddle we harm the intonation even further by shortening the speaking length if the saddle is angled.

If you think that the amount of forward movement in the break point over the saddle is minimal now add it to the amount of shortening of the speaking length because of the neck folding into the body and it's problematic.

Lots of physics here by the way which I personally enjoy a great deal.