How to solve a hump around fret 12 ? - Jemsite
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post #1 of 18 (permalink) Old 04-19-2015, 05:09 PM Thread Starter
 
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How to solve a hump around fret 12 ?

I have this Cort KX5 here, bolt on maple with rosewood neck, tune o
matic type of bridge. Fretbuzz start to occur form fret 7-17 while
neck bow clearance is fine. There appears to be a hump starting from 7
to 17 (neck/fretboard, and thus frets), and it even remains there when
I adjust truss rod until a straight neck. in that case, my stewmac
notched straight edge makes contact from about 2-6, then I get worse
lift off, until it makes contact again around 13 (max of the hump) and
then takes of gain until the end of the fretboard. Releasing truss rod
further does not make the situation better.

I thought I'd fix this kinda "Fender hump" by placing a shim under the
top 2 screws in the neck pocket, but since the hump is already halfway
the neck and not around the bolt-on zone, I guess it is not going to
help a lot. Compensating the hump by filing the frets extra in the
hump zone seems a risky job, and as far as I can see, which 'll make
it a worse job, it should be done while the instrument in stringed up
with neck under tension so I know how much to compensate.

Here a picture of the neck in situation with good relief. You can see
the hump with the naked eye.


This is with the neck straightened. It is +/- straight from 0-12, but
then you have this nick that stays.
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post #2 of 18 (permalink) Old 04-19-2015, 06:34 PM
 
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Re: How to solve a hump around fret 12 ?

Sorry to say Silver, but your ONLY options to fix that are to level the frets (all 24) or pull the frets, level the board, and install new frets.

I would be leveling the board and installing new frets myself.

No, the job does not need to be done with the neck under string tension. A flat board is flat whether it's under tension or not.
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post #3 of 18 (permalink) Old 04-19-2015, 06:40 PM
 
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Re: How to solve a hump around fret 12 ?

On a side note: IIRC, you have a couple other nice guitars laying around. I think the Cort would be an excellent guitar to start teaching yourself to do your own neck work and other modding. I wish I'd had something just like it when I started to learn.....
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post #4 of 18 (permalink) Old 04-19-2015, 06:41 PM Thread Starter
 
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Re: How to solve a hump around fret 12 ?

Thx Rgtfanatic. It's a guitar of a friend of mine, so bad news for him. refretting after board levelling is too expensive for this budget friendly axe. A global fret dress will already be quite a job in this case, and I'm afraid the hump is quite extreme, so the frets in the middle of the problem zone are going to get quite a shave... Hmmm :T
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post #5 of 18 (permalink) Old 04-19-2015, 06:45 PM
 
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Re: How to solve a hump around fret 12 ?

Quote:
Originally Posted by Silverburst View Post
Thx Rgtfanatic. It's a guitar of a friend of mine, so bad news for him. refretting after board levelling is too expensive for this budget friendly axe. A global fret dress will already be quite a job in this case, and I'm afraid the hump is quite extreme, so the frets in the middle of the problem zone are going to get quite a shave... Hmmm :T

You'll have to discuss with your friend whether it's better to put money into the guitar or not. I would happily do it for the cost of the new wire, but my wait list is getting long......too long
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post #6 of 18 (permalink) Old 04-19-2015, 07:46 PM
 
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Re: How to solve a hump around fret 12 ?

I would use it for practice or chuck it and buy a new guitar. The cost of repair will exceed the worth of the guitar if you hire a tech to do the job.
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post #7 of 18 (permalink) Old 04-19-2015, 07:58 PM
 
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Re: How to solve a hump around fret 12 ?

this is a bit unusual in an electric solid body. I see this a lot with older acoustics, especially ones that have never been kept in a humidity controlled environment. The board will hump up right around the neck joint and peak between there and the end of the fret board.

i have also seen this on set neck guitars where the wood used to construct the neck, body or both wasn't properly dried. This will cause the joint to bubble causing the same sort of problem.

The others are right though. You will have to do a full level crown polish or full refret after plaining the fretboard level again.
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post #8 of 18 (permalink) Old 04-19-2015, 08:17 PM
 
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Re: How to solve a hump around fret 12 ?

could you buy a replacement neck. You say it's a bolt on - is it standard fender specs

http://www.warmoth.com/Guitar/images...Dimensions.jpg

If so, there are many inexpensive options.
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post #9 of 18 (permalink) Old 04-19-2015, 08:31 PM
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Re: How to solve a hump around fret 12 ?

The most inexpensive option is just to level the frets.

I'm never one to suggest the biggest job is the right job, if it's at the wrong time, and I wouldn't suggest throwing away 80% fret life just to get rid of a hump. When it's time to refret, that's the time to plane the board true. Now is the time to level the frets. You want to do it under tension, and you want to do it in enough relief that you're cutting a little off the first and last frets as well as the hump, so it will minimize the amount of fret you need to remove overall.
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post #10 of 18 (permalink) Old 04-19-2015, 11:49 PM
 
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Re: How to solve a hump around fret 12 ?

Ryc if you're looking for necks to work on I have an '87 RG410 neck that needs a full refret that I'd love to put on my swirled 540P
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post #11 of 18 (permalink) Old 04-20-2015, 12:13 AM
 
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Re: How to solve a hump around fret 12 ?

Doing a level crown and polish isn't extremely difficult but you would still need to buy some tools to do it right. I will try and post the procedure that I use to do LCPs.
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post #12 of 18 (permalink) Old 04-20-2015, 02:55 AM Thread Starter
 
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Re: How to solve a hump around fret 12 ?

Thanks for all the input guts, appreciate it. I'll have a talk with my friend about cost options but it's not a really expensive model. He hasn't played it and was probably on a stand on his desk in the sun half of the time. If it wasn't the most stable aged wood to start with, I can imagine how tensions start to build up under certain conditions resulting in this frankenstein neck.

I recently acquired sanding blocks, fret files etc. Solving some local fret problems have been succesfull, but this is a more extreme problem.

Thx for wanting to share your procedure J
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post #13 of 18 (permalink) Old 04-20-2015, 05:58 PM Thread Starter
 
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Re: How to solve a hump around fret 12 ?

So here is what I did. Local fret dress while under tension. Check every spot with a fret rocker and adjusted until no rocking. It is A LOT better now. Still have to round and crown.



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post #14 of 18 (permalink) Old 04-21-2015, 09:20 AM
 
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Re: How to solve a hump around fret 12 ?

Looks like a decent start man. I wouldn't have done it strung up myself, but your method gets you where you want to be.

For me, working with the neck under tension doesn't give you a clear picture of the true characteristics of the neck. I'm a much bigger fan of pulling the neck and using the truss rod to find "flat". This way I can find the true point at which the truss rod is making relief. It also gives the chance to find any twist, dip, hump, or any other unwanted variation in the neck that is directly being caused by the material itself.

The amount of fret material you took off is very minimal. It makes me wonder if they were ever leveled by the manufacturer. Being at the price point it is, I doubt much more than pressing the frets in was done.

How does it measure out with your straight edge now? Now would be the time to level all of the frets with 220-grit on a known straight sanding beam. You'll only be able to sand a minimal amount with #220, but it will make a huge difference in playability after polishing. BTW.... I like your dot method for marking high spots. It makes it nice and easy to visualize whats going on....... consider your idea stolen....
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post #15 of 18 (permalink) Old 04-21-2015, 01:36 PM Thread Starter
 
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Re: How to solve a hump around fret 12 ?

Thx RGTF
I prefer working on a flat straight neck as well for doing bigger fret dress jobs, but in this case
1. I can't even get the neck flat, see pic 2 at the top.
2. The bump is not consistent. Under tension compared to straight (as possible. So if I'd remove the bump in straight mode, I wasn't sure how it was going to end op in relief mode. So I chose to use a little rocker to check per 3 frets in relief mode and work my way up. This is rather micro dressing than big picture dressing. But I didn't dare to go big picture here. I Was afraid it was going to be like doing a dress on one guitar and seeing the result on another. I had to take care not to create new problems while working on 1 fret, make the hump worse for the next. But by doing this progressively my way op turned out quite ok.

I use a whiteboard marker to top heigh frets. Also handy to see where your file is going and where not.
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