Fretting with neck straight/under tension (confusion....)

[honza992]

Hi all
I hope this is a quick one, and I'm being my usual slightly slow self.

There are lots of threads about fretting with either a straight neck or under tension, either real or simulated. Half say one and half say the other.

I've always fretted my necks straight, because it never occurred to me that it could be done any other way. Now I realise that it can, but I don't quite understand how.

Fretting with a straight neck makes intuitive sense. Get the board flat. Put the frets in. Get them flat, dress them. String up, adjust the truss rod so there is slight relief. Job done.

But how do you fret when a neck is no longer straight, but is under tension, either from the strings themselves or simulated tension, eg the Stewmac neck jig. The tops of the frets are no long level so presumably you can't use a sanding bar along the string path which is what I do at the moment. So how do you fret in this situation? I feel as though I'm completely misunderstanding something, but I can't see what....

Thanks, as always.

 

[Gilmourisgod]

Thanks for posting this, I've had exactly the same question in mind. Seems like if you level frets with string relief in place, all the frets would be at slightly different heights, lower at head and heel, and higher in the middle. Or are you leveling them straight, but set into a board curved to simulate string tension? If that works, why does just setting the neck dead flat and then leveling to that work too? Maybe @Bruce Johnson will take pity on us and weigh in. I can't afford a Stewmac jig, so I was planning on leveling to dead flat.

 

[Rôckhewer]

Well I don't have as many years under my belt like a "Bruce"...but ....

When using the StewMac neck jig the neck IS flat.
But.... flat with simulated string tension.
The first step in using the jig (after strapping the guitar down) is to straighten the neck with the truss rod. And check for a flat board using a straight edge notched out for the frets. Then you zero out the dial indicators.
Then the strings are removed and dials returned to zero by using the adjustment posts and strap at the nut.
So what's the point?
Flat is flat....right?
The main reason I can personally see for using the jig at all.... (other than the fact that the neck is supported extremely well while working the frets)...
Is that, the neck not only bows slightly under string tension BUT ALSO the entire neck flexes forward slightly EXCEPT the last several frets where the neck attaches to the body. So if that area stays fixed & the rest of the neck flexes forward, those frets are going to be, in effect, "ramped up" in relation to the plane of the rest of the neck.
In other words..... the dreaded "ski jump".
So simulation of string tension allows one to truly flatten the frets of the ENTIRE neck, as if it were under tension.
Then the introduction of a little relief WITHOUT the added slope at the end allows for better action without buzzing.

I can't afford a Stewmac jig, so I was planning on leveling to dead flat

Alex...
I think I mentioned this before....but I made my own Erlewine neck jig.... and it only cost about $35 for the dial indicators, threaded inserts & 3/8" all thread. And some extra hardwood I had laying around.

View attachment 938079

 

[Gilmourisgod]

Rock,
Thanks, I think I get it, probably ought to watch a few Youtube videos on the Erlewine jig in use. I had forgotten you made one of these.

 

[honza992]

Rockhewer - thanks for your reply. That does make perfect sense and your jig looks great. I think that's the problem solved!