Sighting down a fretboard

[mandolin breeze]

I know everyone's done it, but how many are doing it correctly and for the right reason? I assume that you are trying to determine if the frets are correct. I know that there is a certain amount of bow allowed in the length of the neck and I don't know how that is factored in during the sighting process.

What exactly are you looking for? Is there a process involved, i.e. first look at this and then look at this type thing? Which direction should you be looking from? When you know precisely what you're looking for, do you get an "exact" diagnosis of your fretboard or just an approximation of the setup?

[George R. Lane]

First thing I look down is the side of the fretboard, I am looking to see if the neck is bowed and the truss rod needs adjusting. Then like your photo to see of there is any warpage.

[Tom Wright]

Twist is visible from either end. I find looking from the bridge better, with a bright window or light shining toward me. You can look for low or high frets that don't make for a smooth, shiny ladder. Dark areas are low. I diagnosed a low fret this way, and also an upturned stretch of frets after the low one (12th). I leveled those down to match the low fret, so that it was a bright, equally illuminated ladder. Plays much better in those high frets now.

Relief/bowing is better measured by holding straightedge on the fingerboard, but it will be visible.

[dunwell]

When I'm sighting down the neck it is only for two reasons. 1) to look for any twist, 2) see if there are any "bumps" or abrupt changes of height in the the fretboard wood itself like too much fall-away in the extension. Everything else for me is setup related. Test frets with clickers, the amount of back bow as measured at the 12th with straight edge and feeler gauges, clearance at the nut/first fret if not a zero fret, string height at the 12th, etc. etc...

Alan D.

[mandolin breeze]

Dunwell - can you describe the "clickers" a little more please. Something you can purchase or easily fabricate yourself? How do you use them? Thx

[Charles E.]

Many years ago I worked in a guitar shop (building and repairing) so when customers would come in with a problem, one of the first things we did was to sight down the neck. One girl, watching me do this, exclaimed " why is it that all you guitar repairmen sniff the peg head?!"

[MikeZito]

When I bought my first instrument, 40 years ago, the tech at the guitar shop sighted the neck (like Tom above) from the bridge up - to this day I find it much more helpful to do it that way. I am a real stickler for a straight neck, and this method works best for me. The only time I sight from the top down is on acoustic instruments, when I am trying to determine if the neck set is wrong. Other guys that I know sight the neck from the top down to look for uneven frets, but I have to admit that I have not mastered that method yet.

[sunburst]

I do sight necks, but only to see if there is excessive bow, excessive back bow, or excessive twist because that is all I can reliably see by simply sighting a neck. If we sight the bindings they can fool us. If we sight the ends of the frets they can fool us. If we sight the frets for even reflections they can fool us. To really determine the condition of a neck and frets I must use tools. Straight edges (the strings themselves can be used as straight edges) of various lengths and calipers to measure fret height above the fingerboard.
Why is it that bindings, fret ends and the frets themselves can fool us?
Bindings, or the edge of an unbound fingerboard can be worn, filed to inconsistency by previous people working the frets, or otherwise not a good indicator of neck straightness.
Fret ends that do not line up in a straight can be following a curve that is not the same as the fingerboard surface. If frets have been filed inward toward the center of the fingerboard for part of the neck length, that can fool the eye into seeing a bow in the neck that is not really there.
Frets that have been crowned by filing can reflect light from different parts of the fret. If a partial re-fret has been done and there are two (or more) different fret profiles the eye can be fooled by the variation in reflection and see low or high frets on a neck with nice level frets.
Bottom line, it's just a rough gauge for rough neck problems, not a fine gauge for fine set up.

[Ivan Kelsall]

Several years ago,i was having a problem with my once owned Weber "Beartooth" "A" style, oval hole mandolin. Unless i raised the bridge to give me a pretty high action,it buzzed down around the 7th - 10th frets. I'd looked along the neck several times & found nothing. I then decided to take it to my local luthier (15 miles away). He took a 2 second glance along it, & told me that the neck was warped. I could have looked along the neck for a decade & still seen nothing !!. I contacted Trevor at TAMCO where i'd bought it,& Trevor very kindly offered to ship it back to Weber in the US,under guarantee, for repair.

However,it was going to take many months to get the job done & as such,Trevor being the gent that he is,offered me the use of a 'used' Lebeda 'Special' free of charge in the interim period. He sent me a few pics.,& i was so taken with the look of the mandoln,& also knowing Jiri Lebeda's amazing workmanship on his own build mandolins,that i asked Trevor if he'd part ex. it,to which he agreed . That's how i ended up with what a superb example of Jiri Lebeda's building skill,
Ivan

[dunwell]

Dunwell - can you describe the "clickers" a little more please. Something you can purchase or easily fabricate yourself? How do you use them? Thx

The clickers are just several pieces of metal that span three frets at a time and are dead flat. I just made some out of 1/4" thick T6 aluminum bar stock since I have access to machine tools. I have three of them that increase in size and are 1/3-2/3 ratio of short to long side. This allows you to start with the longest one to span three frets and go to progressively smaller ones or rotating to use short and long sides as you move up the fretboard.

The way they are used is to rest it lightly on three fret and kind of wiggle it vertically. If the fret in the center is high you will hear/feel the "click" as it rocks over the high point. One does this while sliding the clicker from one side of the FB to the other to find local high points. I use them for quick check on finished fretboards but mostly when doing a fret job or initial build. Note that these are useless unless you have leveled the fretborad wood first. So the actual process is to use a notched straight edge that skips over the frets and rests on the wood. Then tweak the truss rod to get it dead flat. At this point I usually level the fret tops with a glass bottom sanding plane and re-crown the frets. This is where the clickers come in play to locate any frets that are high or specific spots that are high. These get leveled with the crowning file and finally when all is well the frets are polished and the final setup is done.

Hope that long-winded blether answered your question.
Laters,
Alan D.

[Willie Poole]

Sunburst (John)...If there is too much relief in a fingerboard what is the best way to get it back to a flatter shape? Tightening the truss rod may have caused too much bow and I would like to get it to be more flat , some one suggested to me that laying the mandolin down with the strings down and loosening the truss rod while a slight pressure is applied would do the trick but I am not sure I really want to do something that drastic...Any suggestions? It is not my mandolin and I don`t want to really mess up someone`s instrument...If it is a complicated repair and hard to explain then maybe you might want to send me a PM...

Willie

[sunburst]

Willie, It's one of those things I'd have to see to be able to answer. There could be several causes and/or remedies.
When all is working well, tightening the truss rod will straighten excessive relief in the neck. If tightening the truss rod doesn't work, or causes other problems, or it takes too much torque to tighten the rod, then other repair work is needed.
That may not help much, but it's all I can know without seeing the mandolin.

[Charlie Bernstein]

When you assume . . . .

I'm not looking at the frets. I test them by playing each note, not by looking at them.

I look down to neck for bowing. I like straight necks. I don't allow "a certain amount of bow."