Fret slot depth?

Is there a "best practice" regarding the depth of fret slots?

That is, should they be, for example, at least .02 inches deeper than the length of the tang on the fret wire?

And, what is the maximum depth of the slot that is acceptable with a radiused neck? (Referring to the depth in the center of the slot, where it would be deepest if slots are initially cut on a flat fingerboard)....or does it matter at all? (assuming you don't cut through the neck!) :roll:

Thanks!

Don´t cut straight, cut with the radius of the frets.

This is one of those areas that I don't any facts or figures or sound bites or nothin'. It just feels wrong to me to have a gap of air between the bottom of the fret tang and the bottom of the slot. my slots (nut too) are all the same radius as the fingerboard and do not extend past what is necessary to seat the fret. I am probably making more work for myself since there are plenty of folks using a table saw (straight flat on the bottom) to cut slots. It's just how I like to do it.

Is there a "best practice" regarding the depth of fret slots?

That is, should they be, for example, at least .02 inches deeper than the length of the tang on the fret wire?

And, what is the maximum depth of the slot that is acceptable with a radiused neck? (Referring to the depth in the center of the slot, where it would be deepest if slots are initially cut on a flat fingerboard)....or does it matter at all? (assuming you don't cut through the neck!) :roll:

Thanks!

Good question... it's something I struggle with. I err on the side of "too deep" most of the time, so it's a good thing I don't mind the look of filler putty beneath my tangs.

Everyone has their own views on this. While I don't agree with all of them, I respect their opinions. IMHO, speaking strictly for myself, I don't think it matters at all.
I slot when the board is flat. My slots are cut approximately halfway through the thickness of the fretboard. After radiusing and fretting, I do have to fill in the fret slot ends. Not a big deal to me.
I'm only working on my fourth scratch build though, so take that for what it's worth.
However, having said that, all of my builds(IMHO) have sounded great. I can't imagine them sounding better than they already do, and it would be a difficult task to convince me that if my slots were shallower they'd sound a ton better, have more sustain, be more even toned, etc, etc. YMMV.

This seems to be a subject with lots of different opinions.

Are there others who will join this debate?

Thanks!

First off, this is not intended to be part of a debate. Just my input on the subject.

I've started just marking the slots in the miter box when the board is flat. Then after it's glued up and radiused, I take them to final depth with a fret saw and depth stop. This matches the bottom of the slot to the fretboard and references the slot's depth from the top of the board. As for gap under the frets, I like to keep it to a bare minimum...just enough to let CA seep in if need be.

Mark

First off, this is not intended to be part of a debate. Just my input on the subject.

I've started just marking the slots in the miter box when the board is flat. Then after it's glued up and radiused, I take them to final depth with a fret saw and depth stop. This matches the bottom of the slot to the fretboard and references the slot's depth from the top of the board. As for gap under the frets, I like to keep it to a bare minimum...just enough to let CA seep in if need be.

Mark

Thats how I do it, feels best for me too.And never experienced a dead fret doing it this way.

First off, this is not intended to be part of a debate. Just my input on the subject.

I've started just marking the slots in the miter box when the board is flat. Then after it's glued up and radiused, I take them to final depth with a fret saw and depth stop. This matches the bottom of the slot to the fretboard and references the slot's depth from the top of the board. As for gap under the frets, I like to keep it to a bare minimum...just enough to let CA seep in if need be.

Mark

Mark - Thanks!...you are correct....and I agree..."debate" is not the correct or intended word. As someone involved in their first build, though, I was surprised that there were so many different approaches to this subject....and I was unable to find an answer in my search of other threads.

So...."...a bare minimum"...can I assume that is about .02 or so?

Mark - Thanks!...you are correct....and I agree..."debate" is not the correct or intended word. As someone involved in their first build, though, I was surprised that there were so many different approaches to this subject....and I was unable to find an answer in my search of other threads.

So...."...a bare minimum"...can I assume that is about .02 or so?

.020" seems a bit much.

If you shoot for .005" you'll probably end up with .010" and that's plenty acceptable. I doubt anyone is bottoming out every fret and getting them to sit flush on the fretboard as well. They all have some space under them.

Someone here in the forum even cuts blind slots with a Dremil so the tangs don't show at all. It's a cool look for sure but there's still some space under the tangs..

Mark

I’ll agree this is one of those never ending debates Kind of like what’s better Gibson or Fender we all know the answer PRS. I just looked at a couple my store bought necks Warmoth there’s a gap under the frets My Custom 22 PRS has quiet a big gap. What I do is cut my slots on the flat board Then when I radius the board I check to make sure there deep enough When I install the frets I fill the slot with glue forcing the glue down in the slot first. So that takes care of the theory air under the fret will cause a dead sound, if you believe that theory I don’t buy it I just like to glue my frets. Something to remember about guitar building never ending supply of different approaches.

Fresh off the Fender factory tour, they use a drum/rotating cutter that is mounted like wood in a lathe. They then load the necks into a rotating cartridge (think gatling gun barrels) that guide the necks across the blade at the correct arc/raduis. A fender fret slot is a radiused cut. My thoughts would be that they would cut them during a cnc process while they were flat on a table if they were not concerned with the gap.

Great stuff here for the beginner's...like me! Much appreciated.

Fender's method of getting radiused fret slots is fascinating...Thanks, JC!

I've been trying, for days (and sleepless nights) to try to figure out how to do that (radiused slot frets) using the StewMac table saw blade....cutting on a flat surface, I think I'd have a gap under the center of the 21st fret of about .06 inch....even if I have only .005 gap at the edges....but glue may make this a non-issue (?)

Gaps under your frets are in some cases quite important.

Wood expands and contracts. When it does, it's insanely powerful. Just like when your decking wood manages to squeeze a nail out over the years, or ground frost will pop a post out ... fret tangs hard up against the bottom of the slot is asking for trouble.

IMO, the tang must have a gap under it more than the expansion/contraction rate of the wood. If the fretboard shrinks and the fret doesn't, the fret is then left unseated. Then the next time the wood swells the fret is still unseated ... eventually the frets become uneven and need leveling. You can eliminate that first "lift" by making your slots slightly too deep.

Wood wants to expel metal banged into it.

Great stuff here for the beginner's...like me! Much appreciated.

Fender's method of getting radiused fret slots is fascinating...Thanks, JC!

I've been trying, for days (and sleepless nights) to try to figure out how to do that (radiused slot frets) using the StewMac table saw blade....cutting on a flat surface, I think I'd have a gap under the center of the 21st fret of about .06 inch....even if I have only .005 gap at the edges....but glue may make this a non-issue (?)

I think you’re over thinking the whole thing stressing yourself out. If this is your first build I think the main objective should be to end up with a straight and playable neck. I do all my slotting with the Stew Mac power slotting system. Myself I would not even try to follow a radius with it. you would get a better job with a hand fret saw

Gaps under your frets are in some cases quite important.

Wood expands and contracts. When it does, it's insanely powerful. Just like when your decking wood manages to squeeze a nail out over the years, or ground frost will pop a post out ... fret tangs hard up against the bottom of the slot is asking for trouble.

IMO, the tang must have a gap under it more than the expansion/contraction rate of the wood. If the fretboard shrinks and the fret doesn't, the fret is then left unseated. Then the next time the wood swells the fret is still unseated ... eventually the frets become uneven and need leveling. You can eliminate that first "lift" by making your slots slightly too deep.

Wood wants to expel metal banged into it.

As a furniture builder for many years, I know that this is an excellent point. Wood certainly moves seasonally and with changes in humidity...and you must allow for it in furniture building to prevent unwanted "happenings".

Perhaps a small gap of .005, as Mark suggested, and maybe with a "soft" glue (e.g., titebond or silicone(?)) as a "cushion"...this may allow for the expansion/contraction without any serious consequences....

I'm planning to cut my first set of frets tomorrow...all of the above info is very helpful...

Thanks to all!

I think you’re over thinking the whole thing stressing yourself out. If this is your first build I think the main objective should be to end up with a straight and playable neck. I do all my slotting with the Stew Mac power slotting system. Myself I would not even try to follow a radius with it. you would get a better job with a hand fret saw


...and you are "right on", too!....I'm spending too much time thinking about it....when I need to just go ahead and give it a go....Thanks for the advise...which I will follow.

Tomorrow morning, I cut!

This is about tang height/slot depth, right?

Since I use a Japanese flush-cut saw (Ace Hardware, ten bucks) with no "stop" or guide for depth, I place a strip of blue masking tape on the blade, just where the teeth meet the flat of the blade. This gives me about .065 exposed teeth, which is the height of the tang of the fret wire I use. I layout and slot first, drill for dot markers, cut the board's final width and taper, sand for a radius, then go over the slots in a curved motion with the fret saw again, because of course, sanding the radius renders a shallower slot in the center of the board. When the blue tape on the side of the saw hits the fretboard, I know I'm deep enough to allow the fret to seat. This also cleans up any trapped sawdust and crap left over from the radius operation. If my dot marker holes are too shallow due to the radius sanding, I run a brad point bit by hand in the holes to define them and clean them up.

After a couple guitars your own ideas, methods will become part of your personal building process. This group or books will point you in the right direction but you have find what works for you and you will. The only real rule that should always be followed have fun. The only negative your about to start an addiction with no cure, I guarantee this before you guitar is done you will be planning the next on.

The only negative your about to start an addiction with no cure, I guarantee this before you guitar is done you will be planning the next on.


He speaks the truth.

Hi, my name is Mark and I'm an addict. I'm currently on builds 19 & 20. It's been 5 secs since I last thought about playing a guitar.

Mark

Well, I went ahead, taking all the good advise provided, and cut fret slots with the circular saw blade…..using depths calculated for a 9.5 inch radius, by using the circle calculator recommended by PhilCollins, which can be found at http://www.1728.org/circsect.htm

…and installed walnut dots….

Everything looked great!

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…except for that faint center-line which I had scribed at the very beginning of this process, my first neck build…it was much too deep…I had to sand the radius so deep to get rid of the center-line, that I ruined all of my fret slots, and it took the neck down to 1/32 inch less than 1"…..bummer. :oops:

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…so, today, my new StewMac manual fret saw arrived, I recut all of the fret slots….so far, so good…….I guess! …well, the slot depths are now consistent with the radius….and close to .065 inches…..

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…so, I went ahead and installed the truss rod and skunk strip….

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Tomorrow I'll try installing the frets…..

This neck business isn't for those who get easily discouraged, imo!

What else should I be watching out for?

I sincerely appreciate all of the great input! :grin: