The TECHNOFRET Advanced Fret Leveling System (hereafter referred to as the AFL System) takes the art of precision fret dressing to a whole new level.
The system comprises a precision straightedge, and a speciallyground and lapped aluminium channel, 19" long x 1 1/2" x 5/8" ( 490mm x 40mm x 15mm), with two strips of high quality self-adhesive aluminium oxide abrasive, 400 grit and 600 grit. The outer surface of each flange is lapped to a tolerance of less than .0001", it is the flattest, straightest surface imaginable.
In use, the channel flange is slipped under each string in turn, while the instrument is strung up to tension, and gently moved back and forth until every fret shows abrasion.
We have sold hundreds of TECHNOFRET 19" sanding beamsto hundreds of satisfied customers, and in most cases the19" sanding beam will accomplish the task perfectly adequately. The beam, in particular, is wellsuitedto the task of removing divots in frets caused by string wear, and the AFL system is not designed to replace the sanding beam, it is designed to complement it. You wouldn't use the AFL system to mill a fretboard with heavy fret wear.
In some cases ,the operation of dressing the frets with the strings removed will not, and cannot, produce the ultimate in playability, ie the lowest possible buzz-free action.
This is because when a neck is straightenedby adjusting the truss-rod, the frets levelled, and thenthe strings replaced and brought to tension, the fret tops are not totally guaranteed to remain in the same continuous plane that they were in when they were levelled.
The famous Swiss mathematician, Leonhard Euler,back in the 18th century, was the first person to analyse whya slender column under compression can not be brought back to perfect straightness by the application of a counteractive force (such as a truss-rod). What happens is that the column willinevitably assume a gentle S-shaped curve.
In the case of a guitar neck,the closest you can get to a straight line when the strings and truss rod are under tension is actually a slight hollow from nut to about the sixth fret, then a tiny reverse curve from sixth to eleventh. In many cases, this deviation from the straight is so slight as to cause no problem, but in a significant number of cases, it will cause a problem, which will manifest itself as an annoying and inexplicable string buzz, when the action is low. The more slender the neck in relation to its length, the greater the chance of this happening. So, for example, the neck on a 12 fret acoustic is unlikely to suffer from the problem, a 14 fret neck slightly more so, and the neck of a Fender Strat or Tele is greatly at risk.
SO WHAT DOES THE TECHNOFRET AFL SYSTEM DO ?
The TECHNOFRET system is the only commercially available system anywhere in the worldwhich allows the frets to be leveled under exact string tension.
There have been several different "neck jigs" developed which claim to emulate string tension, but a moment's thought will reveal that most of these jigs do not in fact simulate string tension exactly, they only offer a crude approximation.
The only way to truly replicate string tension is by using actual string tension, and that is exactly what the TECHNOFRETAFL System does.
First of all it is necessary to bring the neck as close to straight as possible, either by adjusting the truss rod or, ideally, by using the TECHNOFRETmodular neck jig.To achieve this straightness, an accurate straightedge designed for the purpose will be found to be invaluable. The TECHNOFRET 18" straightedgeuses 3 precision aluminum gauge blocks to measure when the neck is straight, with one block at the first fret, one at the fourteenth, and one at the seventh. Feeler gauges will soon indicate when the neck is straight.Of course, you could use one edge of the AFL channel (without the self-adhesive abrasive) as a reference straightedge, but in practice a separate straightedge will be found to be much more convenient.
The frets are then ready for leveling.
The channel flange is slipped under each string in turn, and moved back and forward gently until each fret has been abraded. Once this has been achieved, thestrings can be removed and the frets crowned in the usual manner. When the instrument is restrung with the same gauge of strings, you will know that the fret tops will still be perfectly straight. You can then dial in whatever amount of relief you want by adjusting the truss rod, with the total certainty that there are no maverick frets which will cause a buzz.
When sanding the frets, the strings will come in contact with the inside of thechannel flange, particularly at the headstock end. It is not necessary to lift the strings, but some people might find the string contact annoying, so it is a simple matter to slip an improvised shim under the strings just in front of the nut, to raise the strings just enough that the channel flange (which is only 1/16" thick) will go under without touching the strings. Ideally, if you want to be a perfectionist,while doing this you should check the tuning at the second fret to make sure that the strings arestill at concert pitch (or whatever pitch and tuning you normally tune the guitar to).
The TECHNOFRET AFL System comprises:
the AFL channel
the 400 and 600 grit abrasive strips
the 18" straightedge
the 3 aluminium gauge blocks.
Buying the whole system ensures a considerable saving compared to buying the items individually, although the AFL channel and the straightedge are available as separateitems. To buy the AFL channel only (including abrasive strips but minus straightedge and gauge blocks) click Here. The gauge blocks are only available when purchasing the whole system.
So, if you require the ultimate in fret dressing systems, invest in the TECHNOFRET AFL system, you will enjoythe bestfret jobs you have ever achieved.