How to plane a fretless neck?

[pdeon99]

My old fretless has developed tiny indentations at the C and D note positions and the fretborrd needs to be "planed". I think the material is probably maple stained black (or maybe ebony - I'll be finding out soon enough when I start sanding).

A local shop says they do this with a long staight straight-edge with sandpaper glued to the bottom. That's something I can make and do at home easily enough.

I'd prefer to remove the nut BEFORE sanding, but it appears glued. How do I release it?

Here's what I imagine I need to watch out for . . .

1) Before sanding, set relief for a straight neck with the strings removed.

2) Apply sanding action to all sections evenly; don't focus on the bad parts

3) expect to re-jig the nut height after sanding.

Anything else?

[The Penguin]

Instead of planing the entire fingerboard for just 2 notes you might want to try filling the grooves, the plus side of this is if you don't like it just plane until your fill is gone and you're back to the original plan.

As for popping the nut try setting a piece of wood squarely against it and tapping to break the glue. Sometimes nuts break but you can usually get them out.

[bgavin]

StewMac Leveling Blocks will do the job for you. I have the 9.5" radius model on order now, to do a defretting job on a P-bass.

[202dy]

Originally Posted by pdeon99

My old fretless has developed tiny indentations at the C and D note positions and the fretborrd needs to be "planed". I think the material is probably maple stained black (or maybe ebony - I'll be finding out soon enough when I start sanding).

A local shop says they do this with a long staight straight-edge with sandpaper glued to the bottom. That's something I can make and do at home easily enough.

I'd prefer to remove the nut BEFORE sanding, but it appears glued. How do I release it?

Here's what I imagine I need to watch out for . . .

1) Before sanding, set relief for a straight neck with the strings removed.

2) Apply sanding action to all sections evenly; don't focus on the bad parts

3) expect to re-jig the nut height after sanding.

Anything else?

Long, accurate straight edges are fairly easy to fabricate if you have access to something flat. How flat is flat? Pretty darn flat is what is called for here. Say plus or minus .001". Cast iron table saw tops are pretty flat but they need to be checked with a precision straight edge to determine if they will do the job. A decent sized piece of 1/4" plate glass is usually flat and can be bonded to a piece of plywood to be used as a reference. Once an ideal surface has been selected, sandpaper in various grits are attached to the reference surface and the straight edge is carefully drawn through. If the straight edge is metal like a 30" aluminum or steel level, for instance, the edge is blued so that low spots can be seen. If hard wood is chosen as a straight edge pencils can be used to mark the wood. Finish the surface of the straight edge to at least 600 grit. The smoother the surface, the easier it is to remove any PSA and paper from the edge while moving through the grits.

A lot of folks recommend taking off the neck and relaxing the truss rod so that the neck is straight. It sounds good but ignores the fact that when place under string tension many necks will exhibit some irregularities in the playing surface making this method a crap shoot at best. The trick to getting a neck straight is to be able to have the neck straight in the playing position with the strings at tension and then recreate the same condition with the bass horizontal on the bench with the strings removed. It is difficult to do without a jig.

Stewart MacDonald's radius blocks are good for truing a radius. But for leveling a fretboard the radius beam is what is used. The blocks are too short to guarantee a true and level board. At a hundred and twenty bucks US it does not make economic sense for most folks to purchase this tool. The other thing to think about when using radius blocks is this. There are two types of radii to which a fingerboard can be shaped. One is cylindrical and the other is conical. For cylindrical think of the side of a jar and for conical think of a traditional pub glass. The radius blocks form a cylindrical radius on the board. There is nothing wrong with this. But the conical radius flattens out as it the further it moves from the nut allowing for lower string height at the bridge end of the neck. This makes it easier to reach across the strings and is especially handy when playing extended scales and arpeggios in the upper positions.

The conical radius is achieved by using the straight edge in the lie of the strings. Simply follow the edge of the fingerboard on each side and imagine where the strings are and stroke the leveler along those lines, too. Actually, instead of four lies on a four string it is usually easier to do five or six. It also helps to use some bluing while performing this. Use a white pencil for this. Once the neck is level, finishing strokes made in an X pattern can be employed to blend it all together.

Fender style nuts can be loosened by knocking on them with a small wood block and a hammer from both sides. If it is glued in this will release the glue most of the time. A dull pair of end nippers or diagonal cutters can be used to "walk" the nut out of the slot. Traditional Martin/Gibson/everybody-else nuts can be knocked on and will usually pop free. The caveat on all of the nuts is that before attempting to remove it to use a very sharp blade to score the lacquer that comes into contact with the nut. Pay special attention to the sides of the nut where the scoring must be performed free hand. Exacto #11 blades or a surgical scalpel blades are highly recommended.

[pdeon99]

Wow, 202DY, that response should become a sticky, or an article in the new TB Wiki section.

With the cost of proper tools, my igorance of the issues, and fact that this is a seldom needed job on my own guitars, I have decided to get it done by a pro.

But thanks to your post, I can now interview the pros to determine if they, if fact, know what they are doing and have the tools themselves. Case in point - I have 2 quotes from pros - one with a stellar reputation for guitar repair, and one at 2/3 the cost from a shop who claims to know what they are doing - yet all he said was that he 'sands it down using a straight edge'.

[pdeon99]

Originally Posted by 202dy

A lot of folks recommend taking off the neck and relaxing the truss rod so that the neck is straight. It sounds good but ignores the fact that when place under string tension many necks will exhibit some irregularities in the playing surface making this method a crap shoot at best. The trick to getting a neck straight is to be able to have the neck straight in the playing position with the strings at tension and then recreate the same condition with the bass horizontal on the bench with the strings removed. It is difficult to do without a jig.

So, let's see if I get this. The major resurfacing job (to get the fretboard down to the level of the indentations) would need to be done first with the fretboard dead straight. Then, what you are saying here, is that when string tension and neck relief come back into play, there may be some uneveness introduced by the nature of the wood, and those need to be dressed out with the neck in that position - presumably with the shorter blocks - and a jig is needed to get that neck relief bowed without having the strings on. Do I understand that right?

[202dy]

Originally Posted by pdeon99

So, let's see if I get this. The major resurfacing job (to get the fretboard down to the level of the indentations) would need to be done first with the fretboard dead straight. Then, what you are saying here, is that when string tension and neck relief come back into play, there may be some uneveness introduced by the nature of the wood, and those need to be dressed out with the neck in that position - presumably with the shorter blocks - and a jig is needed to get that neck relief bowed without having the strings on. Do I understand that right?

Sort of. Kinda. The problem with this method is that when the humps and dips show themselves the act of getting rid of them can cause more humps and dips. And the chase is on. It can take literally hours to chase them all down or more importantly not chase them all down. On a four string fretted instrument there may be eighty to ninety six contact points. A high fret or two at the end of leveling is frustrating but easy to find and relatively simple to remedy most of the time. But even then it can be a wild goose chase if the fingerboard is not right because it is the foundation on which the frets are installed. On a fretless the contact is infinite. Seemingly it's not a problem until you find yourself slightly out and you move a finger to re-tune the note. If that happens at a physical problem spot the musical problem becomes a larger one.

This is why the neck should be jigged before any work occurs. Once properly jigged, the fingerboard is in the same condition it is when it is strung at pitch and the truss rod is adjusted so that the surface is as straight and true as it can be. Then it is a simple matter to true the 'board and string it up avoiding the wild goose chase that can occur every other way.

The argument can be made that they do not do it this way in the factory. That is true. It is also true that a certain percentage of these instruments are not quite right when they are sold. Some will be sent back as unplayable and replaced by the manufacturer. The manufacturer expects this and it is factored into the price of the instrument. The rest are owned by folks who may not have a problem because it exists on a part of the neck they do not play or on notes that are not in keys that they normally play. Others are not bothered by the occasional buzz or grind. An exacting player or an advanced player can be driven around the bend by the same buzzes. That includes many who read or post on TB.

[jeffhigh]

pdeon99,
Your original plan was fine , don't worry about jigs or raduis blocks, it will work just fine the way you described.
The use of jigs is controversial, those who have them (a substantial investment) swear by them, but a lot of luthiers see no real advantage.