Sunday, February 15, 2009

FRETTING

This was in many ways new territory for me. Not that other processes hadn't been too but once you have gotten the hang of using a plane and a chisel, it doesn't really matter whether you are caring a brace or the heel. With fretting I felt like I had to learn to use new tools and materials.

I used LMI's FW74 medium fretwire.

PREPPING THE FRETSLOTS
Because of the compound slope and relief that was worked into the fingerboard after the fretslots had been cut, they needed to be deepened a little in order for the fret to be seated properly.

I set my fretsaw to cut cut a 2mm deep cut and started recutting the slots from the nut and onwards. It was tedious work as the saw kept jamming. In hindsight I should probably have taken the time to resharpen it and adjust the set,
but as I was pressed for time I just muscled my way through it instead.

It worked fairly well on the slots below the 12th fret but once I went above trouble started. To protect the soundboard I used the plexiglass apron I used for final planing and sanding of the fingerboard, and though it did protect the top, it also made it very difficult to keep the saw in the slots. A few times the blade of the saw hit the plexiglass and made it jump out of the slot and making a shallow cut next the fretslot. I could have kicked myself three times (it happened three times).

I managed to do a fairly invisible repair by filling the rouge cuts with 5 minute epoxy mixed with sawdust from the fingerboard and scraping it flush.

Last thing to do was to bevel the edges of the slots with a triangular file to prevent tearing of the fingerboard surface if and when the frets need to be pulled out and replaced down the road.

INSTALLING THE FRETS
The frets were
cut with a regular set of diagonal wire cutters. I cut them roughly 1/4" too long and placed them sequentially in a little holder I made from some scrap cherry. The first 10 frets were then hammered in with an 8oz plastic hammer, Starting at the middle of each fret working my way out to the ends. These were done with the neck supported by a block of wood. Frets number 11 to 15 were also hammered in but with the support of the bare heel resting on the workbench. Frets number 16, 17, 18 an 19 were pressed in using a regular bar-clamp and a piece of fingerboard scrap as a caul.

As I examined the results I couldn't help but notice that the frets had not gone in as cleanly as I had wish for. Most of them had areas where they weren't seated properly. Not disasterly so, but enough to be detected by the naked eye. I gave it another go with the hammering, but it didn't really accomplish much, even when pounding harder than I would think necessarry. I don't really know why that happened. I had checked the slot depth quite meticulously prior to installation
and had the fret slots had insufficient depth it would have mostly likely been at the center. My unseated fret segments seemingly occurred in random places. I speculate that the saw kerf might have been too narrow for the job.

Also a product of a rushed job, no glue was applied to the fret tangs before the frets were hammered it. I only came to think of this after the task was completed.

LEVELING THE FRETS
First the fret ends were cut off flush to the fingerbard with a set StewMac's ground down end nippers. It was a really nice tool. Easy to handle and gave a nice and clean cut.

For the fret ends I had made a little jig to hold a 2"x6" diamond stone. The jig is quite simple, basically a block of plywood with a slot in it. One of the faces is square to the slot, allowing the fret ends to be dressed flush with the fingerboard edge, the face on the other side was cut to give the fret ends a 35 degree bevel.

First the little bit of fret tang that was leftover was ground down a 325 grit coarse stone inserted into the square side of the jig. Then the fret ends were beveled, first by cutting the 35 degree bevel with a 325 grit coarse stone and finished up with a 1200 grit extra fine stone. The fret ends were ground down just enough for the bevel to extend onto the fingerboard. The extra fine stone left the the fret ends with a nice semi-dull surface. I looked really slick.

The leveling was done with the diamond stones too, again first with the 325 grit, then the 1200 grit. They worked wonderfully. I tired to do keep the leveling to a minimum, but the less than perfect setting of the frets necessitated that I had to take off a little more until all the frets showed at least a little bit of flat surface on the crowns.

DRESSING THE FRETS
With a little protective steel fingerboard guards from StewMac place around the fret, I began to restore the crowns of the frets with a medium fretfile until only a
thin uniform peak of flat surface was left. Before going any further I tested the levelling with Stewmac's little fretrocker, a tool that proved to be a handy little device. To my relief I only detected a few spots where a fret was protruding and needed to be taken down a hair by a light stroke or two with a fine file, but all in all it was pretty bang on.

Before the final polishing, first a piece of 320 grit, then 600 grit wet/dry sandpaper was used to run over the last bit of flat to smooth the crowns over. The final polishing was done with a little white ceramic polishing wheel fitted on a Dremel. I also have the green wheels, but tests done prior to the actual fret job proved they were considerably more abrasive, and spelled danger for creating dents and other irregularities to the frets. The white wheel, just left a nice smooth surface.

The sharp edges of the fret ends received a similar treatment.

FINISHING THE SPLIT 19TH FRET
I looked and looked to find information about how to deal with dressing the inside fret ends following the soundhole curve. Courtnall's book has no text, but a little photograph of them being filed 'free hand'. Bogdanovich' book has no information at all, neither does Cumpiano, or so I thought. Only after I had installed the frets, I noticed a sentence advising to shape the 19th fret ends before installation, under the section on installing the frets. Hmm...

Now that they were in, they had to be dealt with in another way. As The fingerboard didn't sit flush with the soundhole, a file couldn't be used. Instead I resorted to carefully grind them flush using the Dremel tool with a small sanding drum, trying only to grind away at the frets and not hit the fingerboard end and it kind of worked. The fret ends themselves ended up pretty nice, but the tangs less so. In hindsight it would have been better to follow Cumpiano's advice and at least trimmed the tangs before setting these frets. Next time!

The frets ended up with a crown between 1.02 and 1.08mm, with the lowest ones on the treble side.


BEVELING FRETSLOTS

CUTTING INDIVIDUAL FRETS TO SIZE

HAMMERING IN FRETS ABOVE THE 15TH FRET

CLAMPING IN FRETS BELOW THE 15TH FRET

NIPPING FRET ENDS

BEVELLING FRET ENDS

LEVELING FRETS

CROWNING FRETS

FINISH SANDING FRETS

CHECKING FRET HEIGHT
DRESSING FRET BEVEL EDGES
POLISHING FRETS

FINISHED FRET WORK


FINISHED FRET WORK

No comments: