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So I'm building a fretless bass right now, and things were going pretty well. I spent all weekend working on the neck and got the CF strips epoxied in, truss rod slot routed, maple markers inset on the fingerboard, my logo inlaid. It all looks really good. I got the fingerboard glued to the neck, got all the markers and my inlay sanded down, sanded the board to 400 grit. I should've known something was waiting to throw a monkey wrench into things...

My fingerboard seems to be rather unlevel, despite having sanded with a Stewmac radius block. I tried to get a good shot showing the problem.




There seems to be a couple of high spots, and also it seems to have a small hump where each of the markers is. So there's something obviously wrong with my process, and I'd really like input on things to correct. Here's what I did:

- made sure neck was flat
- used the thin double-stick tape to secure the sandpaper to the block
- used a guide on one side to make sure my sanding block was tracking properly

The areas where I *think* the errors occurred are as follows:

- sanding on push and pull stroke
- too much pressure applied to sanding block
- sanding block possibly too short. I'm using the 8" block from Stewmac.


Input, thoughts, suggestions, mocking...

Hi Roger: You didn't do anything wrong so relax and even pat yourself on the back for a job well done, so far.... But there is more to do now and that will address the fret plane.

Board levels cannot be done in a precision manner with a short radius block. We use sanding beams that we shop-made that have been precision flattened to around .00025". The length for a bass should be slightly longer than from the nut to the 12th.

The process is working the leveling beam in the direction of the strings on the board until you are hitting everywhere. Beyond the 12th we mill in some fall-away and use a shorter beam from the 12th to the last.

By the way once a board is leveled in this manner you will have also made it a compound radius board which is not a bad thing to have, some folks prefer them and on a fretless bass it would be a good idea too.

OLFer Murray makes and sells the beams for a very reasonable sum. You can take a look here and this page will get you to his ebay store: http://technofret.com

Remember that strings are straight edges of sorts too and that's why it's important that we endeavor to see the fret plane as your strings do.

You're almost there, just a bit of leveling to go!

Hope this helps!

One thing that I do if I have a high spot near the middle, is to sand it down first so the beam does not teter on that high spot. I'll draw a zigzag pencil line down the board as an indicator of the spots that have not been sanded. A precison straight edge is invaluable. I always follow the string paths and never go sideways. Just my amatuer 50 cents worth

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Good going Dan!

Ok, so you guys don't use a radius block, but actually a straight beam? I've got one that's 24" and is milled to within .005", so I'll work as you guys suggest and take my time doing so.

Thanks a bunch for the input. Here's a pic of the bass so far. I've got pretty high hopes for it, so I was rather disappointed from the setback over the weekend.

Ok, so bad news. I just spent an hour going slowly and methodically with 180 grit. The board is worse now than when I started.

Are you supporting the entire neck in a flat neck rest? It almost sounds like you are not supporting it and you are getting flex as you try to sand the FB. I have a neck rest that I made that supports a neck from the nut to the heel. I also have another small one that supports the bottom of the heel. I use shims under that to be sure the neck is completely supported the full length.

I made this mistake early on in my repair career. I figured the neck and truss rod would be enough to keep them flat but soon realized that a neck is quite flexable and will move as you work on it.

I don't have anything a fancy as Hesh does with his .00025" precision flattened sanding beams and I just use an old aluminum carpenters level that I have cut off to 18" but I can get very good results with my home made stuff. I also sand with the string path to make sure I keep things level.

Something is moving somewhere so you need to isolate what is happening before sanding any more.

If your sanding beam (or what ever you use is level you can't help but make the FB flat. So that tells me something is moving.

Maybe Hesh will have a better idea than I do but that is my take on it.

BTW, Nice looking guitar you have there. When it is done it should be killer!...

Bob

I just saw the link to the UK guys offering fret leveling beams...

Are they good quality? They are cheap in both shipping and price compared to Stewmac. I use a thick piece of maple to level fingerboards but would be nice if I can find something more precise (I plane the maple on a jointer first so it's reasonably flat)

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Yep. The neck isn't carved yet, so it's a flat plank being supported down the full length by my work table.

Well then, If your neck is supported and the tool you are using to sand the neck is flat then somewhere something is moving other wise it would have to be flat.

Possibly your bench is not flat? The back side of your neck is not flat? Or possibly there is some sawdust under the neck causing it to be flexed when you sand it.

Double check everything twice...

Bob

And now you see why I'm so perplexed

Don't wave the white flag...

There is a reason you are not getting it level you just need to find it.

A couple other things to look for. Check to make sure your neck isn't cracked and it is flexing up and down while you sand. And check to make sure your fretboard is glued down completely. That could also be flexing under pressure.

Set it up as if you are going to sand it and put your straight edge on it and then push on the high spots and see if you can flex it down.

Check the back of your neck with your straight edge as well as your bench or what ever your neck is resting on. Also check your sanding block for flatness.

As I said, there is something moving or not flat. If that were not the case then you can't help but make a piece of wood flat.

Bob

Tai Fu we made our own and we have about 20 of them in various lenghts, etc. But I have been talking with OLFer Murray and I'm pretty secure that he understands our needs and has a quality offering. I've also come to like Murray too. I agree that the price is great and had these been available when we made ours I would have preferred to buy them instead of make them. It took me an entire day on the surface plate to level just a few of ours so this is clearly one instance where if time is money to you, and it is to us, these sanding beams are a hell of a deal!

I have one and it is very good; I would certainly recommend it

Yeah it is a great looking ax - very nicely done Roger!

OK here's what I would do. First .005" off is too much believe it or not.... SInce we are leveling the board any imperfections will be transmitted to the tops of the frets since they sit on that board. So it's imporant to really level a board not only for the joy of doing a great job even if you go insane in the process... but your next steps, fretting, fret dressing, will all be way easier if you start out with a proper fret board, nice and level.

1) Either level that level that you are using on a surface plate or replace it with a proper sanding beam. Be sure to check the level as well for flex, the leveling beam should have NO flex in it what so ever.

NOTE: When working the beams the neck should be very well supported because they will flex, some more than others.

2) Make pencil marks all up and down the fret board. The primary beam should be long enough to span from the nut to the 12th. A secondary, shorter beam will be used for from the 12th to the last.

3) With the long beam hit the board lightly between the nut and 12th and see where you are in contact with the pencil marks. Now beware if the beam is longer than say from the nut to the 12th it may be riding on the board in the 14th thru the last area. If this is the case stop step three and place some masking tape on the abrasive on one end of the short beam. Keeping the tape over the area of the 12 as you work the beam from the 12th to the last tracing the string paths mill this area down. This is "fall-away" or more specifically the intentionally milling of the board after the 12th to be progressively lower from the 12th to the last. Make sense?

4) Once the board is not being contacted by the long beam after the 12th repeat step three with the long beam and see where, between the nut and the 12th the beam is in contact with the board and the pencil marks. If you are hitting in the middle only there is a hump - get our the truss rod wrench and adjust the neck until the beam is hitting in the nut rea and the 12th. This may take a few attempts, usually does, and basically all we are doing now is getting the neck as straight as we can before going after the low spots. This is less work too, my way to be....

5) Now after milling the board down between the nut and the 12th until you are hitting everywhere and removing all of your pencil marks AND the fret positions after the 12th are not being touched you have leveled your board.

6) Touch-up the fall-away area with the short beam again with the tape over the abraisive keeping the tape over the 12th so as to not mill that area down. The tape also creates a slight downward angle toward the body which is just what we want to induce fall away.

7) If there is much leveling to do I use 80 grit initially and then go to 120 when I am close. No need to put a final sanding on the board at this point either beceuae in the fretting process when sanding the scratches off the frets you will progressively go to 800 grit or so and that takes care of the board too.

Let me know if you have questions. You may have to get different beams too which will become MUCH more important for the fret dressing so might as well do it right.

Ok, so here's the next wave in the plan of attack. I'm going to use my Grizzly 6" long bed jointer table as my work station to eliminate any chance that it's my work surface that's contributing to the problem. I'll then get one of Murray's leveling beams to make sure it's not my current beam. The board is in pretty rough shape right now (unevenness, flat spots, inconsistent radius), so at this point, I'm basically starting with a worst-case scenario. It's good in one sense because it'll give me a chance to work out this process. If it comes down to it, I'll end up planing the board off and ordering a new one.

Thanks for the input, guys. Hesh, I'm sure I'll be contacting you for further pointers as I go. I'm extremely frustrated at this point, but in order to get better and make better guitars, this is the kind of thing I have to get through.

I just looked at the Stewmac site and the UK seller for the fret levelers. It seems the price is about the same. Stewmac offers a 16" leveler for about 47 dollars and the UK 19" one is about 40 dollars when converted to dollars. Hardly seems like a good deal especially when the Stewmac ones is made of tubular steel, which is much harder, less prone to scratches or being bent than aluminum. I need a leveler, I just realized I sanded the fingerboard of a recent build into a concave shape by accident... and it has a little playability issue because of that. It looks like I'll have to refret it to fix it.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Mark the board with pencil and move the sanding beam gently without pushing down hard. Move the beam precisely along the string paths, with no rocking. Sand the zone for one string at a time. Before starting, hold a straightege without sandpaper straight down a string path and get a mental image of where the wood needs to be removed. Then after every one to three straight strokes of the sanding beam, look at where the pencil is dissapearing. Only keep going if the result of every three strokes or so is exactly what you expected. Keep checking with the plain straightedge and using the pencil. Start sanding gently, don't put a lot of muscle into it until you are sure you can guide the beam exactly and you have a clear mental picture of where the wood needs to be removed.
Inspect the neck, while flexing it, for cracks or glue gaps. Are you positive the truss rod has no goofiness? A traditional single rod in a curved channell needs a smooth top piece to pull against. You said you had the neck back supported on the table, but what is holding up the weight of the body?
That's a beautiful instrument, you're almost done. With a fretless, you can finely adjust the board under actual playing conditions by lowering the saddle untill you notice where the string is quieter and louder. Loud spots are where a little wood needs to be sanded away, and quiet spots are in the "shadow" of a highspot closer to the bridge. By doing this test with all four strings up to pitch you can really even out the instrument.

Thanks Leonard. This is a dual action truss rod, and the channel was perfect. Also, the neck isn't attached to the body at this point.

I should also let everyone know that I've built about 12 guitars at this point, so I do have a pretty good handle on most things. That's not to say I can't improve my processes, but I'm not really a noob at this point. For some reason, though, this bass has been kicking my butt. My usual fretboard prep includes using my router jig (well, it's actually Marty's router jig) to get the radius, and then to a finish sanding. It's always been good enough so that any small variations in the board are easily dealt with during the fret leveling stage. With this being a fretless, though, I want it to be much better. Getting this process down will only help my regular guitar builds down the road.

Just wanted to let everyone know that I got my leveling beam from Murray today, so I'm off to try and get the fingerboard squared away. Hesh, I've printed off your instructions to follow, so hopefully this should get everything taken care of.

I've started by removing as many potential problems as possible. I mounted the neck to the outfeed table of my jointer, so I know the surface on which it's mounted is straight and rigid, and I'm using Murray's sanding beam, so I know the device I'm using is perfectly flat and rigid as well. Now the only potential for problems lies in my technique. That's not terribly comforting...

Roger, I hope you don't mind if I interject a quick question. My necks seem to come out pretty good but .... are you guys only using the leveling beam? I've been putting a 16" radius in my boards first, putting in the fall-away, and then cleaning up the string paths with the beam. Am I doing too much work (the radius block is a PITA)?

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Steve Smith
"Music is what feelings sound like"

Over the years I have noticed that the flatness of the fingerboard can change after the neck is carved. This just happened today on a Maple archtop neck. There was a little hump in the middle of the fingerboard when the neck was square and it went away after it was carved making leveling easier. Stress relief?

I always wait until the neck is carved before leveling and do it with the neck attached to the instrument and supported as you have done. I always put a little tension on the rod, even a two way.

I start with a straight radius but as has been mentioned draw white pencil lines all over the fretboard and level in line with the string runs for the most part.

I use a plane body as shown by Frank Ford a number of years ago on Frets.com.

I usually install the side marker dots last after leveling.

I just did one today and snapped a picture.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

Well, I'm cautiously optimistic after my sanding session on Friday. Things appear to be much better at this point. I'll be leaving for a work trip on Friday and will be gone for a week, so I won't get to the neck carving for a couple of weeks. I'll be more comfortable after that happens, so stay tuned...