How much compensation?

Tenthumbs

Hi guys,

Attempting my first-ever build of any kind of guitar so please go easy on me. 

My idea is for a silent guitar in a headless design which entails having the tuning machines at the 'wrong' end of the guitar. I want a classical-width flat fretboard on a 25.5" scale and I've done most of the donkey work already, making it up as I go along in my own inimitable way. The guitar is solid-bodied and will have a built-in headphone amp; I've used some very old poplar wood for the body and neck - which is carved out of one piece - and got to the point where I'm essentially finishing off details. 

I've made a bridge from some zebrano I bought for the purpose, milling the 1/8" slot for the bone saddle with an end mill in a milling machine, parallel to the edges of the bridge. As the guitar will need amplification, the slot is deep enough to accommodate the under-saddle piezo pickup. I've temporarily clamped the nut in place so I can measure the position for the bridge, but after I've done the calculations for the actual string length from the Stew-Mac site I find that there's quite a difference in lengths between the 1st and 6th strings and I think it looks odd.

Tenthumbs

Tenthumbs

Trying to add a photo here - it's in a Facebook album but isn't appearing when I paste in the URL - any ideas . . . ?

Tenthumbs

https://www.mediafire.com/file/4crdgpov0opjz5g/Saddle.jpg/file

ICBM

Is this for a nylon-string guitar? If so there's usually not much, if any, significant difference between the 1st and 6th strings.

If it does need any compensation, the normal way to do it is either to rout the slot at an angle across the bridge, so the bridge itself is fitted square to the centreline of the guitar, or to compensate the top of the saddle - most often for the 3rd, within the width of the saddle itself.



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Tenthumbs

Ahhh . . . That's really helpful. I *could* re-make the bridge with an angled slot or do as you say and compensate the saddle. If I was going to compensate the saddle would I set the scale length to 25.5" square to the centre line from the inside face of the nut to the centre of the saddle? Thanks  

ICBM

It depends how much compensation you want - if you're aiming for as much as the StewMac chart shows you'll need to use the whole thickness of the saddle, so I would set the front face of the saddle to the scale length. None of the strings will intonate further forward than this, and it's usually about right for the top E which needs almost no compensation.

Tenthumbs

I don't have the experience to know how much compensation I want - I'm a complete novice at this as explained so hoping to get it as close as possible. The StewMac chart doesn't differentiate between steel and nylon strings - it asks whether the guitar is electric or acoustic in a drop-down menu but it may assume that the default is steel in any event. In my ignorance I wasn't aware that nylon strung guitars need less compensation - and as one of my college lecturers was fond of saying, 'In the Kingdom of the Blind, the one-eyed man is King . . . ' 

Thank you for your advice - I'll try setting it square to the centre-line at the scale length as you say and if it's a mile out I can easily make a new bridge with the slot in a different place . . . ;-) 

ICBM

I think you'll be fine with it set square to the centreline.

I've never built a nylon-string guitar (well not properly, I did once create a sort of Frankenstein's monster of a thing out of a broken one right at the beginning of my guitar-playing history...) but I've worked on a lot, and never found one that needed any more compensation than could be got within the thickness of the saddle itself. In fact, the vast majority were fine with a traditional plain saddle. Nylon strings are just much less affected by the extra tension of fretting than steel.

Tenthumbs

Fact is, this is really a rehearsal for building a better one - I've got some nice mahogany from a fireplace I scrounged (if it's good enough for Brian May . . . ) so I'd like to find all the 'gotchas' before I ruin some nice wood. Be nice if this one played well right from the start, all the same . . . 

 Thanks again for your help!