Help trying to get a neck as straight as possible with strings off

[gormsby]

Of course Bruce said it better and in way fewer words: https://www.talkbass.com/threads/fr...asked-a-thousand-times.1669100/#post-28978358

 

[Stagelab]

Of course Bruce said it better and in way fewer words: https://www.talkbass.com/threads/fr...asked-a-thousand-times.1669100/#post-28978358

So with Bruce’s approach, you loosen the rod till it’s basically protruding, then tighten it till there’s a hint of backbow when checking the fret tips with a regular straightedge? Is that right? Or do you tighten it just enough for the regular straightedge to show the neck has started to bend in the direction of a backbow, which could be an actual backbow or maybe not, depending on the amount of bow in the neck when the truss rod was fully loose?

I don’t have a straightedge long enough to span all the frets. The longest I have is a 16” aluminum beam, which I use for leveling.

I guess the notched straightedge I bought is useful for checking if a neck is inherently flat but beyond that, is there any value in it and for what kind of repair work?

 

[gormsby]

Different truss rods are different, and I've never seen one protrude as a result of adjustment, so can't speak to that. I typically use dual-action rods. I think of it as loosening the rod to "neutral" in the sense that it's not applying any force to the neck, then tightening it until it engages and the neck begins to move. I can feel when it hits that point. That could mean no backbow if the neck has a slight forward bow in neutral, or just beginning to backbow if it's straight when neutral, or a little more backbow if it had any backbow in neutral. In any case, the hope would be that once it has that starter load, the tops of the fret are "level enough" that a final leveling can be done without taking off too much or taking any fret too low.

I can't recall if you determined your notched straightedge was indeed straight (aside from the notches). If so, is it notched on both sides? Can you lay the un-notched (in-between) parts on the frets? I use a 24" steel ruler that I check against the feed table of my makerspace's jointer every now and then.

 

[Stagelab]

Different truss rods are different, and I've never seen one protrude as a result of adjustment, so can't speak to that. I typically use dual-action rods. I think of it as loosening the rod to "neutral" in the sense that it's not applying any force to the neck, then tightening it until it engages and the neck begins to move. I can feel when it hits that point. That could mean no backbow if the neck has a slight forward bow in neutral, or just beginning to backbow if it's straight when neutral, or a little more backbow if it had any backbow in neutral. In any case, the hope would be that once it has that starter load, the tops of the fret are "level enough" that a final leveling can be done without taking off too much or taking any fret too low.

I can't recall if you determined your notched straightedge was indeed straight (aside from the notches). If so, is it notched on both sides? Can you lay the un-notched (in-between) parts on the frets? I use a 24" steel ruler that I check against the feed table of my makerspace's jointer every now and then.

That makes sense.

I thought this Squier had a dual action rod. if I loosen it a lot the nut begins to come out. Anyways, I know what you mean about feeling it when you tighten the rod and you start to feel a little resistance.

My notched straightedge is notched on both sides. It’s one with a 34” and a 35” side. I could bring it to Home Depot to check it against a granite countertop. Then again, at this stage I wonder what use I have for it. I could see value in using one to evaluate the neck of a bass before buying it, to avoid buying one with a brutal twist, but otherwise I’m now not so sure there’s much value in it.

 

[gormsby]

Anyways, I know what you mean about feeling it when you tighten the rod and you start to feel a little resistance.

That's what you're looking for.

Check it at Home Depot and if the major/outside edge is flat, you can still use it for this, just with the notches between the frets so you're assessing the tops of the frets relative to each other. And that use case for checking necks for reasonable straightness or bad twists is certainly valid.

 

[Stagelab]

That's what you're looking for.

Check it at Home Depot and if the major/outside edge is flat, you can still use it for this, just with the notches between the frets so you're assessing the tops of the frets relative to each other. And that use case for checking necks for reasonable straightness or bad twists is certainly valid.

You mean placing the straight edge so the flat parts rest on the frets instead of in between them?

 

[96tbird]

You mean placing the straight edge so the flat parts rest on the frets instead of in between them?

Yes.

Look if you’re levelling frets, and you use the notched, all you can ever do without planing the neck is get it as flat as it is naturally NOW, TODAY. A few spots where a bit of space shows isn’t a problem. THE ACTUAL GOAL IS that The FRETS need to be as flat as possible; hence “leveling frets”. Even If you are working with SLIGHTLY wonky WOOD LEVELS, you can still achieve level frets. That’s the goal. Otherwise you have to pull the frets, and re-plane the neck.

Just as a minor ski jump neck can be fixed by leveling the frets out at the heel, rendering the instrument playable again up high, a full fret levelling is exactly the remedy for a SLIGHTLY wonky neck. If you’re shooting for perfection, the frets will have to come out.

 

[Stagelab]

Yes.

Look if you’re levelling frets, and you use the notched, all you can ever do without planing the neck is get it as flat as it is naturally NOW, TODAY. A few spots where a bit of space shows isn’t a problem. THE ACTUAL GOAL IS that The FRETS need to be as flat as possible; hence “leveling frets”. Even If you are working with SLIGHTLY wonky WOOD LEVELS, you can still achieve level frets. That’s the goal. Otherwise you have to pull the frets, and re-plane the neck.

Just as a minor ski jump neck can be fixed by leveling the frets out at the heel, rendering the instrument playable again up high, a full fret levelling is exactly the remedy for a SLIGHTLY wonky neck. If you’re shooting for perfection, the frets will have to come out.

Makes sense. Glad I can use the notched straightedge as a standard straightedge to check the frets themselves. For a sec I thought this tool was largely gonna be useless for me. Gonna go to HD to check it against some granite. Philly Luthiers says they verify these tools for straightness before shipping them out so I’m hopeful it’s flat.

As for the neck carving prep, I’ve adjusted the truss rod so it has a tiny amount of resistance, following Bruce’s method. This might not matter so much for neck carving but it gives me some peace of mind anyways.

I’ll do the same approach with the truss rod when I’m ready to level the frets. My understanding is that if you pinpoint high frets, you should use a short beam to sand them down some (ensuring you don’t overfile till they become shorter than the other frets) before using a long beam to leave all the frets, reason being it is a way to avoid removing excess fret material. Lmk if you disagree.

 

[gormsby]

You mean placing the straight edge so the flat parts rest on the frets instead of in between them?

Yep. As long as your granite countertop test (or other trusted surface) shows that the outside edge is indeed straight. In my sloppy drawing (neck on bottom, straightedge on top), the red lines would still be an interrupted "straightedge". Shift it up and over a fret-width or more from normal usage, and there you go.

 

[Stagelab]

That's what you're looking for.

Check it at Home Depot and if the major/outside edge is flat, you can still use it for this, just with the notches between the frets so you're assessing the tops of the frets relative to each other. And that use case for checking necks for reasonable straightness or bad twists is certainly valid.

About adjusting the rod till there’s some resistance, on this Squier neck once I get some resistance I’m only maybe a half turn of the rod till it’s tight. Is that small degree of travel normal? At this point, the neck has gone from a clear forward bow to a smaller forward bow.

 

[Dirk Diggler]

OK now I get where you're going, and to be honest, the back of the neck and it's thickness has the most miniscule effect on the tops of the frets which is what you are eventually striving for. That said sure get it straight, shave the back, then level your frets and be happy.

Ditch the slotted tool, not at all needed. Like comments above I have never seen the need for that tool, I trust my eyes.
I would bet all those YouTube videos are by non-builders, and non technicians.

I'd suggest listening to folks that have actually done what you are attempting to do.

Best of success to you.