Straight vs Radius leveling beam

[RVA]

Mates,

Do you level your frets with a straight leveling beam in the string path or a radius beam? Assume the same length for each beam.

I have been using beams with a radius to match the board, but I was surprised to find this method rejected by many as either unnecessary, removing too much edge material or too difficult to do accurately.  Before reading this in numerous places, I had considered a radius beam to be the gold standard.

Thanks for any input on this issue. 

[Bizman62]

I've used a straight beam, 2x4 cm aluminium beam cut to 28 cm length. Why 28 cm instead of the full length of the fretboard? Because wet'n'dry sandpaper sheets are that long!

I've been wondering whether I should get a long radiused beam and use it for fret leveling. Didn't think it might chew the edges but now that you mentioned it, it's kinda obvious. You can't see what's happening under a long wide beam. With a narrow beam you can immediately see where you've sanded the marker off the fret. Also you can't do a major damage by just a few strokes. Still I find the idea of a radiused beam tempting.

[henrim]

Straight. For reasons you already mentioned.

[Asdrael]

Straight. If you even slightly rotate a radiused beam, you will mess it up.

5 hours ago, Bizman62 said:

Why 28 cm instead of the full length of the fretboard? Because wet'n'dry sandpaper sheets are that long!

Not sure how high of a grit you level with but you can get fairly cheap rolls up to 320 grit on Amazon for example. No more length limit!

 

 

[RVA]

1 hour ago, Asdrael said:

Straight. If you even slightly rotate a radiused beam, you will mess it up.

 

Thanks for the reply. 

Do you mean rotate it to an angle with respect to the fretboard edges? Presumably, since the radius is ultimately a circle, if you move the entire length left or right equally, but still parallel to the fretboard edges, it will be the same as if the middle is centered, since the radius is ultimately a circle. 

[henrim]

Elaborating on my previous reply. Why I say straight is the best, is based on assumption that the work is done freehand. If done without any support a radiused block can easily twist and eat too much from the fret ends. But if you build a jig of some sort that keeps a radiused block tangential and straight then a radiused block could work better. 

In my experience there is so little to correct that a straight block works just fine. If I had to do several necks a day I know I would figure out a better way, though. Although in my thinking there shouldn’t be anything to level if all the previous stages are done perfectly. That is not how it is in the real world but I’m getting closer

[RVA]

So given the fact that the fret ends are not touched with a straight beam, and assuming that it may be necessary to take off more in one string path than another, the radius of the frets will vary from the radius of the fretboard and the bridge on fixed radius bridges. My assumption is that most think this is not an issue, or much less of an issue than the dangers of a radius beam. 

Edited February 24 by RVA

[Bizman62]

9 hours ago, Asdrael said:

Not sure how high of a grit you level with but you can get fairly cheap rolls up to 320 grit on Amazon for example. No more length limit!

I start with 400...

[Andyjr1515]

I'm a bit late to the party on this one but yes - I also use a relatively narrow straight beam (1"/25mm).  It makes it easier to keep straight and, as I move progressively across the width of the fretboard,  I can keep tangential to the curve of the frets better.  The metal filings you can see as you are sanding also give a good gauge to any lines missed and the general progress towards flatness.

What I do do, however, is finish off with a standard radius block with some emery to smooth out any facets I may have left across the width of the frets.

Finally, I use the same radius block pushed across the frets (so doing 3-4 at a time) to get the starting sanded 'grain' direction on the frets the same as that of the subsequent re-crowning/polishing.

  

[RVA]

So when you all use a straight beam, are there any concerns for the loss of a fret wire radius that matches the fretboard? I have not used a straight beam in a long time, but it seems that the curvature will become somewhat randomized depending on the varying degree of work needed in each string path. Does this even matter? Maybe it matters less with height adjustable individual saddles as opposed to a wraparound bridge? 

[Bizman62]

2 hours ago, RVA said:

are there any concerns for the loss of a fret wire radius that matches the fretboard?

I've never even thought about that, the process feels so natural.

Also, especially if I've hammered the frets in, the inconsistency of wood may allow the fret wire to sink deeper into some spot, causing a dip in the fret and obviously all frets will have to be leveled to that lowest point. As you seem to fear, that may cause the frets actually having a different radius than the fretboard, and if the radius of the bridge matches with the fingerboard but not with the frets that might be something you could feel. Was it you or someone else who started a discussion about matching radiuses with fretboards and bridges a while ago? Anyhow, the conclusion was that if they don't quite match some may feel playing on such a guitar a bit uncomfortable and others may not notice any difference.

If you think about the amount you're actually taking off the crowns of frets when levelling you could calculate the change in radius. Knowing that the amount is very little, the difference is not like comparing a 9.5" radius to 12", it's about thous. If you've radiused your fingerboard to 12" the radius of unleveled frets would actually be about 12.05" if the frets sit level to the board. But what happens if you use a 12" caul on a press? Will the centers be a bit proud off the board or will the edges compress the wood? There's a ton of variables so changing just one may not make any difference.

[Crusader]

I think others have said much the same thing but here's my 2 cents

I use a radius beam in a jig to keep it straight, same when I sand the radius in the first place. But if I wanted to get a higher degree of fret levelling I would use a flat bar (Got to get around to buying one) If the fretboard has been radiused really well then there should be very minimal requirement for the flat bar, and less fear of ruining the radius

[Bizman62]

18 minutes ago, Crusader said:

(Got to get around to buying one)

Your local metal warehouse will sell you any length of square aluminium tube, or you may even find a suitable piece at a demolition or construction site - that kind of tube is widely used for supporting board walls in toilets and such. Of course it will need some truing but the tools needed for that should already be in your box.