Compression Fretting vs Planing the Board

[LouieAtienza]

Originally Posted by mirwa

The topics get steered of course, by those that interject a second opinion on a conversation being held between someone else, they may personally feel they have been affronted, they may feel they have a duty to speak out, its irrelevant the reasons why, this sometimes gets heated opinions, sometimes that does not get heated, in the above instance you will note I never replied to loui's last comment, this was becuase I felt he may have been affronted by my statements and taken them personally which was not my intent, as such I left the conversation with loui having the last say, but never have I been so condescending to another person that asks for help on a repair such as that I referenced above.

Steve

Steve, you're obviously a skilled luthier with years of hands-on experience, with advice I generally agree and respect. I'm happy you see how the last post I commented on could be misconstrued, and if it wasn't your intention to direct that personally I accept that.

Realize too that this is an "open" forum, and unless you PM your discussion to someone, then it's basically open season. Otherwise this wouldn't be a forum.

I agree that there is a lot of misinformation on the Web... but that is the reason folks come here, to hear from the guys and gals that actually do the work. But it's just like any trade or craft; there'll always be good and bad.

Originally Posted by LouieAtienza

John, do you think the change to tang frets eventually ushered the use of adjustable truss rods in Martins, since the barbs on the tangs would eventually dig into the slot walls, reducing their force on the neck?

Not John, but I don't think so. Martin switched to T-frets in 1934 and didn't introduce adjustable truss rods until 1985. IMO that was a result of two things - the then new Low Profile neck, and the 3/8" square tube which never held relief as well as the 1/2" steel T-bar.

[LouieAtienza]

Originally Posted by Todd Yates

Not John, but I don't think so. Martin switched to T-frets in 1934 and didn't introduce adjustable truss rods until 1985. IMO that was a result of two things - the then new Low Profile neck, and the 3/8" square tube which never held relief as well as the 1/2" steel T-bar.

Interesting, thanks for the info. I recently watched a Martin factory tour video and they were installing 2-way truss rods in their necks... as well as more automation..

They went to 2-way rods around 2006. IME the 2-way rods are a bit more touchy. I don't like them and much prefer 1-way rods, and with a traditional Martin neck, I've never needed to force forward bow which is what a 2-way can do.

Martin had issues with the early Micarta fretboards back bowing under string tension with the 1-way truss rod loose. They introduced the 2-way rod to fix that, and when that worked out well, they made it standard to simplify parts inventory. I believe their problem was tight fret slots on the Micarta boards. They don't compress as much as ebony or rosewood and resulting tighter fret tangs induced a back bow.

[mirwa]

I should refrain.

In this mornings deliveries, (Store stock New Martin) authorised warranty repair for lowering the action and setting up.

Three pictures grouped

Picture 1 - Strings tuned, truss rod fully dis-engaged, measured relief 5"
Picture 2 - Strings removed, truss rod fully dis-engaged, measured at 14th, 8" required to stabilise rocking of straight edge.
Picture 3 - Close up of 14th fret and 8" gauge





Steve

Steve, there may be issues with that guitar, but it has nothing to do with compression fretting as a method of controlling relief since Martin doesn't use compression fretting on adjustable truss rod guitars.

[Tom West]

Originally Posted by

Picture 1 - Strings tuned, truss rod fully dis-engaged, measured relief 5"
Picture 2 - Strings removed, truss rod fully dis-engaged, measured at 14th, 8" required to stabilise rocking of straight edge.
Picture 3 - Close up of 14th fret and 8" gauge


[IMG

http://i1379.photobucket.com/albums/ah149/steven_simpson1/mar_zpsq5yynbtl.jpg[/IMG]


Steve

Love to see folks working with correct measuring tools, but being a machinist in a former life I think you may be out a few decimal points on your quoted measurements.
Tom

[redir]

I have to say, I'm still confused. Can we back pedal to the beginning again?

The OP is about fixing a guitar with a non adjustable truss rod that has a bowed neck. That is a neck with too much relief. His solution was to level the neck. Whether you call that leveling or planing it's just semantics, the same thing.

On a neck with too much relief leveling will remove a small amount of material from the area of the nut and possibly the body joint. Once strung back up to where string tension pulls in a bit of relief it ought to be good to go.

The second solution is compression fretting. The theory there being that when you release string tension the fretboard will bow back to straight and then you put in wider frets so that when you put string tension back on the 'kerfs' of the fretboard don't close as much and hence the neck doesn't bow as much.

That makes sense, however; even the experts who do compression fretting say that the first step in doing so is to level the fretboard.

Hence my confusion.

The only think I can think of is that compression fretting is good on instruments that have weak necks that bend a lot under tension.

But regardless in either method apparently you start off by leveling.

[mirwa]

Originally Posted by Tom West

Love to see folks working with correct measuring tools, but being a machinist in a former life I think you may be out a few decimal points on your quoted measurements.
Tom

Didn't notice as I was typing it, yes their is a big difference between 5 thou and 5 inches

Steve

[Bruce Sexauer]

Originally Posted by redir

I have to say, I'm still confused. Can we back pedal to the beginning again?

The OP is about fixing a guitar with a non adjustable truss rod that has a bowed neck. That is a neck with too much relief. His solution was to level the neck. Whether you call that leveling or planing it's just semantics, the same thing.

On a neck with too much relief leveling will remove a small amount of material from the area of the nut and possibly the body joint. Once strung back up to where string tension pulls in a bit of relief it ought to be good to go.

The second solution is compression fretting. The theory there being that when you release string tension the fretboard will bow back to straight and then you put in wider frets so that when you put string tension back on the 'kerfs' of the fretboard don't close as much and hence the neck doesn't bow as much.

That makes sense, however; even the experts who do compression fretting say that the first step in doing so is to level the fretboard.

Hence my confusion.

The only think I can think of is that compression fretting is good on instruments that have weak necks that bend a lot under tension.

But regardless in either method apparently you start off by leveling.

I call what you are referring to a "leveling" in your quoted post as "dressing". What I mean by dressing is bringing the fingerboard surface to to the lowest common denominator and having a consistent surface. This is like a fret mill but on the wood before fretting. This usually has nothing to do with correcting relief. If the wear is too significant I will sometimes fill finger divots because I do not want to remove so much fingerboard, but this is uncommon, especially in ebony.

[Rodger Knox]

The one thing that everyone seems to agree on, is that we are talking about miniscule differences, mostly less than 0.01". That's pretty small.

I'm in the school that builds a little relief into the board, even though I use a two way rod. There's a couple of reasons, but the may not be relevant. Most people like a little more relief on the bass side, and the easiest way to get it is to sand/scrape/plane it into the board. By putting the relief into the board, you can put it where you want it, the truss rod doesn't always get it in exactly the right spot. That's kinda splitting hairs, but that's the nature of this topic. If the relief is in the board, all the truss rod has to do is hold the neck straight, and you still have the adjustability to change the relief if you need more or less than is built into the board.

The important point is that differential relief across the board usually requires that to be built into the board.

[LouieAtienza]

Originally Posted by Rodger Knox

The one thing that everyone seems to agree on, is that we are talking about miniscule differences, mostly less than 0.01". That's pretty small.

I'm in the school that builds a little relief into the board, even though I use a two way rod. There's a couple of reasons, but the may not be relevant. Most people like a little more relief on the bass side, and the easiest way to get it is to sand/scrape/plane it into the board. By putting the relief into the board, you can put it where you want it, the truss rod doesn't always get it in exactly the right spot. That's kinda splitting hairs, but that's the nature of this topic. If the relief is in the board, all the truss rod has to do is hold the neck straight, and you still have the adjustability to change the relief if you need more or less than is built into the board.

The important point is that differential relief across the board usually requires that to be built into the board.

I'm in general agreement on this. Saves a little guesswork as to how and where the neck wood will bow under tension. Rather simple to design in CAD. Tougher to preserve the same curvature in the frets themselves, but I so that by carefully installing the frets and checking them to insure they're seated as consistently as I can. The big benefit to this as opposed to fixing the surface of the tops of the frets is that each fret ends up a more consistent height. Even thought of ways to do the fret job on my CNC similar to Plek (but without their software). Not there yet, because it would take considerable prep work, set-up time and custom fixturing.

Although the difference is miniscule, for lowest action even a couple thousandths could mean excessive buzz. Many people prefer the lowest action that doesn't buzz; I personally prefer the highest action that I can still play easily.

[jessupe]

Originally Posted by LouieAtienza

I'm in general agreement on this. Saves a little guesswork as to how and where the neck wood will bow under tension. Rather simple to design in CAD. Tougher to preserve the same curvature in the frets themselves, but I so that by carefully installing the frets and checking them to insure they're seated as consistently as I can. The big benefit to this as opposed to fixing the surface of the tops of the frets is that each fret ends up a more consistent height. Even thought of ways to do the fret job on my CNC similar to Plek (but without their software). Not there yet, because it would take considerable prep work, set-up time and custom fixturing.

Although the difference is miniscule, for lowest action even a couple thousandths could mean excessive buzz. Many people prefer the lowest action that doesn't buzz; I personally prefer the highest action that I can still play easily.

I agree with both of these post's. Highest action yet able to play easy for prolonged periods of time. Beyond the "Feel" thing I like this because it leaves "room" for dropped tunings, I find myself rarely playing in standard tuning and I notice many of the players I'm exposed to also play dropped tunings often.

Related to set up I get very bummed out if I tune down merely to a low D and it starts to buzz, let alone C.

[mirwa]

Originally Posted by John Arnold

That is easy....when the brace has been hacked down so small that it is not sufficient to maintain structural integrity or acceptable tone.
Where I live, I see a lot of amateur brace scalloping. I believe it is a cultural artifact in Southern Appalachia.....the isolation meant that you fixed things yourself, regardless of your ability.

Interestingly enough, on today's job sheets, another X - Brace replacement.

Steve

[murrmac123]

"interesting" bracing layout, to say the least ...