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How Flat Does The Fretboard Need To Be Before Fretting?


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Hi all,

Reckon I already know the answer to this one, but here goes:

I have glued my fretboard onto my neck, and when looking down the 'board I notice it's not completely flat and level.

There are several undulations along the length of it, sometimes most of a millimetre of difference. They are visible as gaps along the length when I hold my straight edge along the 'board. (The straight edge is totally straight, I did check BTW!)

The 'board was bought pre-slotted and pre-radiused. It's made of ebony.

The neck surface was TOTALLY flat before glueing.

I think it's possible that my clamping was not a total success!

It's also possible that the board was not entirely flat when I bought it!

Anyway, I'm left wondering how flat the 'board surface must be before fretting........and I'm pretty sure the answer will be: very flat.

I just can't see how the fret levelling would be able to compensate for that amount of variation in the 'board surface.

Are all fretboards entirely flat and level before fretting??

(Perhaps you could get away with a very minor deviation from straight??)

I don't have another fretboard without frets in it to look at for a comparison either.

I have other necks to look at, but all you see are the frets when you try to look down the length.

So, assuming I will now have to do some sanding/levelling: what's the best way to get the 'board level?

Appreciate anything helpful.......

Could post photo if rqd.

DJ

Edited by djhollowman
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Photo would help.

I level my fretboards with a carpenters level covered in 80 grit abrasive. You want it *very* flat. Adjust the trussrod to get it as close to flat as possible, and then level it with the carpenters level. Once it's level, I re-radius, check for level, and keep working at it with the leveller and progressivesly finer grits of paper until itls levelled and smooth.

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get it as flat as humanly possible - the more work you do now the easier and better your fret job will be.

I use standard radius blocks, sanding back and forth along the entire length to rough radius/level it. That tends to create a dip in the middle so then i concentrate on either end till its nearly level then finally sand along the whole length in one direction only. Definately not the best way and i would prefer something longer to save all the pissing about but i havnt got around to sorting it yet. My point is that you should be able to get a level board even with basic tools, it just takes more checking and thought!!

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get it as flat as humanly possible - the more work you do now the easier and better your fret job will be.

I use standard radius blocks, sanding back and forth along the entire length to rough radius/level it. That tends to create a dip in the middle so then i concentrate on either end till its nearly level then finally sand along the whole length in one direction only. Definately not the best way and i would prefer something longer to save all the pissing about but i havnt got around to sorting it yet. My point is that you should be able to get a level board even with basic tools, it just takes more checking and thought!!

thanks Wez! That's just exactly what I thought!!

Hmm...........gonna have to make a radius block after all! Thought I'd get away with that by buying a pre-radiused 'board.....knickers!

Ah well, better get on with it................

So, would a radius block which is as long as the fretboard be the real answer??

DJ

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So, would a radius block which is as long as the fretboard be the real answer??

DJ

Yeah - those aluminium ones stew-mac sell look the business. definately on my wish list

http://www.stewmac.com/shop/Tools/Sanding_...ing_Blocks.html

you can use something like this if you already have a radiused board

http://www.stewmac.com/shop/Tools/Special_...d_Levelers.html

you just need to be carefull not to change the radius, straight sanding along the length only. You can probably find something else locally that will do just as good a job, like the carpenters level setch suggested.

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So, would a radius block which is as long as the fretboard be the real answer??

DJ

Yeah - those aluminium ones stew-mac sell look the business. definately on my wish list

http://www.stewmac.com/shop/Tools/Sanding_...ing_Blocks.html

you can use something like this if you already have a radiused board

http://www.stewmac.com/shop/Tools/Special_...d_Levelers.html

you just need to be carefull not to change the radius, straight sanding along the length only. You can probably find something else locally that will do just as good a job, like the carpenters level setch suggested.

Yes, I've seen those at stewmac's site.

I had been trying to source everything locally cos of the delivery costs, but soon I'll have enough items required to make it worthwhile placing an order from them!

Wondering if my local engineering firm could provide me with a steel box-section that would be flat/straight enough.

I have a 24" level as well, could try that!

Thanks Wez!

Edited by djhollowman
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Having a perfect radius is only important if that feels right to you - it's much more important to have the board be flat along it's length, so that the wood under each string path is flat, whether you're talking a compound (conical) radius or a consistent (cylindrical) radius. The radius exists mostly to make the board more comfortable under your hand. Of course you want your radius to match what your bridge can achieve without having to jigger it all up or slot the saddles very deep. I've played older cheap guitars where the fretboard radius seems like it had to have been done freehand on a belt sander or something - rather than a continual radius arc, it curves much more at the sides of the board - I guess if you drew the radius out, it would look like half an oval rather than a portion of a circle. But with the string paths perfectly flat, it still played great. Felt a little weird though - I wouldn't want to build something with that sort of radius - I guess what I'm saying is that you may be able to get things reasonable with long flat tools rather than a radius block.

I certainly think you can do fine without a super long radius block - I get things roughed in with straight lengths using a carpenters level as mentioned below, or something similar. I make sure the center of my board is perfectly flat before I do my radius. I also carefully take a bit off the edges to start roughing in the radius, while keeping things reasonably level down the whole length.

The flat area down the length in the center of the board gives me something to watch as I put my radius on with a radius block - once I've only got a small line of untouched wood in the middle, I know I'm there - (marking the middle of the board with white pencil helps this stand out) if I see that "untouched" area is getting thinner more in one area (like the middle of the board) then I back off sanding there. (Working towards having that line in the center is sort of the same concept as crowning frets where you try and leave that perfectly thin marker line)

If the center line of your board (or whatever the highest point of your radius is, I suppose it doesn't have to be the center) isn't flat before you start, it's easy to follow this method and still end up with an undulating board - you've just duplicated the dips and valleys along that center line across the entire radius!

Remember when done to check the flatness of the board across the string paths, not just the center!

While tweaking the rod to get things closer to flat can help when leveling, avoid messing it around too much - I did this on one of my early builds only to find out that I had shot myself in the foot by tweaking it a little bit too much and after putting strings on the thing, was unable to get the board back to flat! Of course, if you have to tweak it in the right direction to get flat, you've just compensated for string pull, and you might not have to use the rod at all after stringing it up. Although, after putting carbon fiber in my necks, I hardly ever need to adjust the truss rods at all - which makes a flat board more important!

You could avoid all this board levelling and just use really tall frets!

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Having a perfect radius is only important if that feels right to you - it's much more important to have the board be flat along it's length, so that the wood under each string path is flat, whether you're talking a compound (conical) radius or a consistent (cylindrical) radius. The radius exists mostly to make the board more comfortable under your hand. Of course you want your radius to match what your bridge can achieve without having to jigger it all up or slot the saddles very deep. I've played older cheap guitars where the fretboard radius seems like it had to have been done freehand on a belt sander or something - rather than a continual radius arc, it curves much more at the sides of the board - I guess if you drew the radius out, it would look like half an oval rather than a portion of a circle. But with the string paths perfectly flat, it still played great. Felt a little weird though - I wouldn't want to build something with that sort of radius - I guess what I'm saying is that you may be able to get things reasonable with long flat tools rather than a radius block.

I certainly think you can do fine without a super long radius block - I get things roughed in with straight lengths using a carpenters level as mentioned below, or something similar. I make sure the center of my board is perfectly flat before I do my radius. I also carefully take a bit off the edges to start roughing in the radius, while keeping things reasonably level down the whole length.

The flat area down the length in the center of the board gives me something to watch as I put my radius on with a radius block - once I've only got a small line of untouched wood in the middle, I know I'm there - (marking the middle of the board with white pencil helps this stand out) if I see that "untouched" area is getting thinner more in one area (like the middle of the board) then I back off sanding there. (Working towards having that line in the center is sort of the same concept as crowning frets where you try and leave that perfectly thin marker line)

If the center line of your board (or whatever the highest point of your radius is, I suppose it doesn't have to be the center) isn't flat before you start, it's easy to follow this method and still end up with an undulating board - you've just duplicated the dips and valleys along that center line across the entire radius!

Remember when done to check the flatness of the board across the string paths, not just the center!

While tweaking the rod to get things closer to flat can help when leveling, avoid messing it around too much - I did this on one of my early builds only to find out that I had shot myself in the foot by tweaking it a little bit too much and after putting strings on the thing, was unable to get the board back to flat! Of course, if you have to tweak it in the right direction to get flat, you've just compensated for string pull, and you might not have to use the rod at all after stringing it up. Although, after putting carbon fiber in my necks, I hardly ever need to adjust the truss rods at all - which makes a flat board more important!

You could avoid all this board levelling and just use really tall frets!

Thanks a lot, that's good advice, and very useful!

I'm currently sanding it flat using 60grit paper on the narrow edge of a 24" level, and this is working very well.

I see what you mean about not forgetting about the non-central edges of the 'board.

I scribbled all over the face with a pencil, to show up where it was low.

My only concern now is that the 12th fret inlay [a beautiful chinese symbol, done on a CNC machine] is where the highest point is, just hoping I don't have to go right thru it with the sanding! Should be OK.

After a few more hours I should be where I need to be - I really do see the value of getting it flat at this stage!

DJ

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Although, after putting carbon fiber in my necks, I hardly ever need to adjust the truss rods at all - which makes a flat board more important!

How wide and high must the Carbon Fibre Rods be to have stability effect in a neck?

I only seem to find 1x6mm material locally.

Are you in UK?

I would also be interested to know much more about carbon fibre rods.......

DJ

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Maybe I'm wrong, but I think I can see a gap between your neck and the fingerboard. Either your neck wasn't 100% flat before you glue the fingerboard or maybe your clamping wasn't successfull? It's possible that the FB wasn't properly radiused but that would surprise me a lot. I ordered several FB from Stewmac and LMII, and they were always perfect.

Edited by MescaBug
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Just a thought......and it is a thought as I have ne experience of this.

If the depressions were caused when you clamped it, could a bit of gentle heat be used to spring it back out again (as you would with a little ding). Obviously it would depend on which glue you used , but might be worth a try before you spend the next few days sanding.

I'm sure one of the experienced guys will give you a yes or no on this, so wait for that before trying it.

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Just a thought......and it is a thought as I have ne experience of this.

If the depressions were caused when you clamped it, could a bit of gentle heat be used to spring it back out again (as you would with a little ding). Obviously it would depend on which glue you used , but might be worth a try before you spend the next few days sanding.

I'm sure one of the experienced guys will give you a yes or no on this, so wait for that before trying it.

Not good IMO. You wouldn't want to soften the glue with heat, and if the wood is compressed(doubt that though, because the softer shaft wood would be crushed), you don't want to introduce water into the mix as it will make the neck even less stable until it settles and you resurface again.

If you want to improve your clamping. Use the appropriate amount of glue(not too much), and use a nice clamping cowl to distribute pressure evenly. This can help cut down on sanding if the fretboard is true before you install it.

You really want to get the fretboard spot on. This is the secret to not having to do much of anything to fretwire. The time you spend now allowing the neck to stabalize and getting a true surface on the fretboard. Will save you three times as much work grinding down frets, and re-crowning (which is going to give a poor final product, as your putting year of wear on the frets when you do this). Many of the suggestions above are great. Use them and get that fretboard wickedly true. You will appreciate how well this works after you install the frets.

Peace,Rich

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Maybe I'm wrong, but I think I can see a gap between your neck and the fingerboard. Either your neck wasn't 100% flat before you glue the fingerboard or maybe your clamping wasn't successfull? It's possible that the FB wasn't properly radiused but that would surprise me a lot. I ordered several FB from Stewmac and LMII, and they were always perfect.

Yeah, clamping was not as good as I would have liked! My own fault. You live and learn I guess!!!

Not to worry, I've now flattened the 'board again with a long level sanding stick, and it has worked a treat!

Now I'll leave it a few days to stabilize before checking that it's flat again.

DJ

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Just a note on radiusing which I found useful. Start at the end of the fretboard with the end of your radiusing block, then push over the board and off the other end, if you get tempted to use the usual forward and back motion with the block allways in contact with the board the middle section gets more sanding than the ends. If this happens you then have to tidy the ends up (as mentioned earlier) . It may take a little longer but the finish is well worth it

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Does a ROUND Carbon Rod give any real Vertical support, noticeable reinforcement of the Neck?

I gather a Standing, Rectangular Rod would be best.

A bit OT, but....yes, actually a cylindrical rod will give you better support (and more uniform directional support) than a rectangular rod of the same thickness. A tube is even better (lower total stiffness, but higher stiffness/weight ratio than a solid rod of the same diameter).

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Use them and get that fretboard wickedly true. You will appreciate how well this works after you install the frets.

True that. I've only been this lucky once, (and given my current skill level, I'm not sure it wasn't anything but luck) but I've had a board so perfectly flat that I literally had to do no leveling at all on the frets. Now I measured them all out, and thought, wow, that's awesome, but it can't be right. Did my normal fret leveling, and on the first pass, I was hitting every fret. No leveling needed means no real crowning needed, either. Not sure how I didn't manage to even lower one fret while pressing them in. Much nicer than the bass I've got here with mandolin-sized frets after taking almost all the metal off during the level trying to make up for a sloppy board.

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