KM 505 Trussrod - No affect?

[Rockyjohnstone]

Yet another question regarding the KM-505 refret project. Older model non radiused neck. I acquired this mandolin to learn how the do a full fret. I may have gotten a little more than I bargained for. I'm OK with that though, adds to the learning opportunity.

While preparing to level the fingerboard, I discovered that adjusting the truss rod (either direction) has no effect on the neck. Yes, I should have discovered this before now, but honestly I didn't check. I will note that the truss was adjusted fully clockwise and snug upon inspection. The previous owner apparently had it set in this manner.

With the strings (and frets) removed, the neck is basically flat, with the exception of a very slight rise on the bass side between like the 3rd fret and the nut. Several articles and posts I've read recommend creating a very slight back bow, and then sand the neck straight prior to refretting. That's when I discovered the neck remains straight when the the rod is turned fully clockwise or counter clockwise.

Upon searching for answers I found this from an older Cafe post;

http://www.mandolincafe.com/forum/sh...-in-a-kentucky

Which the OP had this picture of a KM truss rod out of the instrument.



I've no idea if the KM 505 I have uses this truss rod style or not. But vintage is around the same as the OP's post, and I am suspecting that may be the case.

Here's what I'm wondering...

If this style rod has been tightened to it's max and then some, (people can get greedy when tightening things) it would seem possible that the underside fingerboard may have been worn to the point where the rod no longer has any effect. Of course this is just theory with zero evidence to back it up. Just a hunch.

I could just move ahead with the refret and see what comes out in the wash, but I wanted to see what suggestions you guys may have to offer. Also wondering if coaxing a little back bow into he neck and then trying to tighten the truss rod nut be worth and shot?

Appreciate any advice on this, as this has me puzzled.

Pete

[David Newton]

If the truss rod does not move the neck with no strings or frets, it certainly will not adjust the neck when you run the strings up to pitch.
You will have to take some other strategy, like sanding some back bow into the fretboard & compression fretting, and hope that string tension does not pull up too much forward bow.
It is too bad that you didn't inspect the amount of forward bow with frets and string tension before you took out the frets.

[Rockyjohnstone]

Understood. I do recall sighting down the neck. It looked dead flat on the treble side with the same slight rise on the bass side near the nut I described earlier. Failing to check the TR functionality, and not realizing it was maxed out was on oversight and rookie move on my part. Arghh...

At this point, I'll have restirng, bring the neck to full tension and let it sit for a few days. Then I can at least have look at fingerboard with a straight edge to assess forward bow. If it remains flat fully when tightened, I'll still need to know how much relief is avaiable by backing off the adjustment. Perhps it's locked up somehow. Thanks David.

Pete

[MysTiK PiKn]

post deleted.

[David Houchens]

If you're in this one for the experience, you might want to remove the finger board and see if the rod is bound up with glue. Try a different rod or install some carbon fiber instead.

[John Kelly]

The truss rod should not have caused wear on the underside of your fingerboard, as there should be a wooden fillet covering the truss rod before the fingerboard is glued on; the rod is embedded in the neck by this means. As Bryce mentions, you might want to try a non-adjustable strengthener, such as steel or carbon fibre, instead of the two-way rod. I use carbon fibre now on mandolins, having previously used a 6mm square steel bar. I feel that mandolins with their short scale do not need adjustable rods - but others will beg to differ, I am sure. Getting the old rod out can be a pain!

[Pete Jenner]

I feel that mandolins with their short scale do not need adjustable rods - but others will beg to differ, I am sure. Getting the old rod out can be a pain!

I agree.

[multidon]

Chiming in to disagree with John and Pete. Sorry! love you guys, but...

All of my mandolins have adjustable truss rods which operate correctly. I can dial in a tiny bit of relief, which I prefer, or not.

It is true I think that a non adjustable rod, steel or carbon fiber, may prevent the neck from bowing. To me that is not a truss rod, strictly speaking. It is a neck stiffener. But what if you develop a buzz that could otherwise be cured with a twist of the rod? You can't.

In short, I like them.

[MysTiK PiKn]

The link you show talks about a different mandolin model.
Is your truss rod the same as the picture? How do you know that?
Does your truss rod use an Allen Key?
Do you know what kind of truss rod you have?
Is the trussrod a 1way or 2way? Or a 1way dressed up as a 2way????
Does anyone know?



I started to respond to this above, and then deleted my post. These questions - that why I deleted it. It seems there's a real mix of information here. Perhaps I am the only one confused - it wouldn't be the first time, no problem.

[Rockyjohnstone]

First off, I appreciate everyone's feedback regarding the KM 505 truss rod concern.

I mentioned in my original post that I could not say for certain that the truss pictured was in fact the same as the KM 505 that I have. Both are Kentucky mandolins of similar vintage. That only suggests there a reasonable chance the truss rods are the same. In any event, I believe I need to get the neck up to tension to see what's up. Obviously a critical misstep, lesson learned.

So starting over on the neck/truss rod analysis.

I've decided not to reinstall frets, but instead will temporarily place thin metal inserts (appx .022 thick) snuggly in the fret slots to keep the slots from closing up when I string it up. I'm hopeful this will work for my purpose.

While I won't be able to measure relief in the traditional way (string to fret clearance), I will be able to measure the fingerboard with a straight edge and examine how much TR range the instrument has. This should get me to square one.

My suspicion is the TR (whatever type it may be) likely works as advertised, but is has reached it's limit in terms of removing excess relief from string tension. As Dave pointed out, I may be looking a compression fretting or creating a back bow in the neck when I sand the fingerboard. A carbon fiber rod sounds interesting, but I'd better keep this as simple as possible. Plus I too like an adjustable neck.

Once I learn how the neck is behaving, I'll chime back in. Thanks for helping me sort this out and get on track which I do appreciate.

Regards,
Pete

[MysTiK PiKn]

I did fret levelling. I did a lot of sighting the neck, frets in, and that made it easy to see the changes w the trussrod. I'm not sure, but you can likely sight a naked neck also - esp. in the right lighting, direct or reflected light. Straight edge did not help me much.

www.frets.com has a lot of info on truss rods and adjustments - also there's a huge writeup on planing a fingerboard on a Gibson F5 - with tons of pictures. It starts with fret removal, goes thru entire process, beautifully tedious.

I don't know if it's a 2way or 1way. To me, if it's allen keyed, it's a 2way. My experience is not extensive. The other thread you linked talks about ibanez 15 yrs, etc. maybe had a 2way rod that was only used 1way - at the factory level, that would make sense, if all they ever did was add a little relief, and never used the "other direction adjustment" of a 2way rod. I'm saying maybe they only used it in one direction. I'm guessing and still confused. Also, I am not familiar with the need to bend the neck before planing - it seems the name of the game is to make it flat. then adjust later. I am willing to be corrected on all that I type here. I'm just not feeling the logic.

If you need more info, frets.com is your friend. Others here have way more experience than me.

[Rockyjohnstone]

In an effort to get a better analysis of the 505 neck problem, I installed some temp shims in the fret slots and strung the instrument up to tension. The one way truss rod does in fact function, has only about .006 of adjustment however. Not sure what normal range is.

Here's the bigger concern;



That's about 1/16" rise, and remains when the tension is removed. The treble side illustrates the same problem with about half that much rise.

Not sure how to proceed.

While just sanding the fretboard straight will take less effort, that looks like a lot of fingerboard to remove me. Might not look right and may be even less stable when finished.

Removing the fingerboard might a better way to go, but I'm sure that creates another basket of problems to deal with. Particularly getting the board off without trashing the finish.

I suspect you guys have seen this many times, any help with best options is welcome,

Pete

[sunburst]

... that looks like a lot of fingerboard to remove me...

Nah... plane it off of there. You'll probably take some off around the 12the fret area in the process, and that will require removing some from the area beyond the 12th fret. You'll want a flat plane from the nut to the 12th fret, then another flat plane from 12 to the end of the extender. That part should drop off about .015".

[Rockyjohnstone]

Thanks John. I appreciate the added detail with the fingerboard extension. I'm relieved to hear I don't have to risk major damage to move on with this project.

Regards.
Pete

[Nevin]

A couple of things. An Alan key does not indicate a two way truss rod. Plenty of truss rods use them. If the problem is the rod works but does not have sufficiant play, one or more small washers can be put on the rod to give it more range. I would back the nut off; clean the threads, use a small amount of a graphite lubricant; put one or more washers on and snug the nut up. Adjust the rod slowly giving it time to respond.

[Rockyjohnstone]

Thanks Nevin -For the record, it has a 5/32 allen nut. I read several articles about doing just what you suggested, adding a washer to get more adjustment from the truss rod. Interesting thing about the truss rod on this instrument...

A recent lengthy thread discussed challenges regarding accessing the truss rod nut due to headstock restrictions. This one is like that as well.

While I could get at the nut to adjust, the cavity is too narrow to get the nut removed. It was getting hung on all 4 sides within the headstock channel. I carefully carved and whittled for a couple of hours and now have 3 sides clear. The top of the cavity is still restricting getting the nut removed, and frankly I gave up... its a tough angle to remove material at the back of the cavity (near the nut) without over doing it on the front if that makes any sense. here's a photo to illustrate.



Notice top of the truss rod nut, that is counter clockwise as far as it goes before it hangs up.

The other concern I have is, I'm not even sure the nut is going to separate from the rod the way it is acting. It's really buried in there, about even with the string nut. It's as if the nut/rod are integrated, as I can hear the other end of the rod clunking around in the channel near the body when it gets loosened. It feels like if I get the nut completely free... the entire truss rod will come out leaving the connecting nut at the other end embedded in the channel near the body. Then what? Perhaps it was constructed this way to keep people from removing the it?

I know this sounds way off base, but remember this may be the same truss rod design (Ibanez style perhaps?) pictured in the beginning of this post. I've no way to be certain without an xray, but that one is surely unconventional by most standards, and this one seems to be acting in a strange way to me.

I wanted to bring this up, so I'm glad you mentioned adding a washer behind the nut.

Regards,
Pete

[MysTiK PiKn]

Picture looks like a rougher version of my 2way trussrod. I do believe it is not possible to remove the nut for lubrication. The part that turns, where the 5/32" = 4mm allen key inserts, connects, locks in, etc. is surrounded by an outer ring, which I guess is like a retainer bushing, or bearing, whatever - the inner core is the hex shape, that's where the allan key goes.
If it won't turn counterclockwise, and if it is functioning, then you reached the max adjustment counterclockwise - and this is max increase of relief. (higher action). If you want less relief, (lower action), it should turn the other way - clockwise - which should reduce relief.

If it does not turn in either direction, then something is very wrong.

this is my best guess - I am still not clear on how you got to this point, or exactly what that rod is. and I suggest again to read before further guessing causes further problems. But, to me, it's a 2way rod.

Also, if it's a 1way compression rod, then clockwise will reduce relief - same as the 2way rod.

If it's some other kind of rod that magically looks identical to my 2way - then good luck - find out what it is. Maybe contact Saga, the manufacturer for more accurate information.

that's all I got. I remain thoroughly confused - and not responsible for whatever is going on here.

It's possible that the rod won't move because you shimmed the fret slots = too tight to move. But it should go the other way, unless those shims are really HUGE. If so, then the truss is jammed by the shims. Ridiculous right?

the mystery continues.

[Rockyjohnstone]

I agree, that nut is not meant to be removed. I suspect my lengthy posts have muddied up the water to some degree. My apologies, and you guys have been great in helping me work through this.

To summarize..

While checking TR functionality, I expected to be able to create a slight bow back without any tension on the neck. Not so, but I've concluded that it's not that big of a deal. It is not stuck, and the neck will move from "flat" to about .006 of relief under string tension. Good enough I suspect.

Whether the rod is a 1 way or 2 way should make no difference. For as long as it gets the job done, I'm happy. I should contact Saga just for sport to see they can provide any specs.

I appreciate everyone taking time out of their day to help me gain a better understanding of this topic. I'll likely have a few more questions as I move forward with next steps like planing and refretting.

Regards,
Pete

[David Houchens]

The fact that you're hearing the rod clunking around is something ( in my experiences ) that should not happen. If the rod is moving in the channel, you may be losing a lot of adjustment before its tight against the finger board.

[MysTiK PiKn]

When I did mine, the neck started with backbow - I went counterclockwise to induce normal "bow" = more relief. To decrease "bow", and induce some "backbow, you want to turn it clockwise. Directional reference is when you look at it from the tuners end, as in the picture. String tension is not recommended, slack or remove them.

Bryce has a point. Assuming it is not broken, and just flopping around in there, it's possible there is simply SLACK in the rod, which can allow some free movement, as in uncontrolled flopping around. I think you should be going to a clockwise adjustment - and I think it's possible that the rod has been forced counterclockwise, to the max - if so, broken might be possible - but the initial turns towards clockwise might be difficult, due to "binding". Either it's broken, or it's over-torqued, or JAMMED. This is pretty messy - but needs to be resolved - make it or break it.

This is not easy to diagnose. Either it's broken, or jammed, or it's going to move in the desired direction. When I was adjusting mine, there were times when I approached maximum adjustment, and the allen key itself was bending. And to undo that required similar force that caused the allen key to bend in the opposite direction, until the rod developed a bit of slack - and then it turned normally. It's TOTALLY SLACK in the mid point.

In all cases, these maximum adjustments were undesirable, as they cause other deformations in the neck. The backbow you seem to want is a slight adjustment, little force. If you exert more force, the "middle area" of the neck will deform - on mine, that made bow resemble more of a V than a gentle curve. After sighting it a million times, I got familiar with how it moved - it is sensitive.

You need to find a best way to sight the neck. I usually sighted from the side of the bridge area. With frets, it's possible to use relatively light and dark reflections to see what's high/low which the eye cannot detect. Sometimes, while sighting, I would reach out my hand to touch a point of interest, because it's hard to locate where those points are, due to the extreme flat angle point of view. It's hard to explain this - but you can see the indescribable, and the neck will tell you what's happening and what to do.

I think you need to determine if that rod is going to function, or be a dead weight. It's possible a previous owner has caused this problem - I don't know the history.

Frets.com has huge write up on these rods, and all types.
Stew-Mac has pictures of these rods, and their installation, and LMI likely does also.
Removal is described as "easy" - but I think it still means pull the fb.
Talk to Saga if possible, email, contact page on Saga site.

[Rockyjohnstone]

I contacted Saga as suggested and learned this,

"It is a "Traditional Two-Way Adjustable" rod. The nut is not removable as far as I know. I can't tell without looking at it if there is a problem with the truss rod, but as you "loosen" it more it should "tighten" the other way. You might want to show it to a luthier to see what they say."

That answers that question. It's a 2 way truss rod and was made in 2009 according to Saga.

I can definitely feel the truss rod tighten when I turn the adjustment nut clockwise. However, when turning counter clockwise, there is no point which any resistance can be felt. Now that I have the adjustment cavity in the headstock clear, (turning counter clockwise) the truss rod tension becomes loose (almost sloppy) and just spins and spins...the nut is not coming off. This occurs whether under string tension or not.

By all accounts, I think it's broken, or at least not working as described in one direction. So before I remove the fingerboard, I'll have it looked at by a pro.

So tell me this? Considering it seems to function as a traditional 1 way truss rod, is it feasible to simply set it up accordingly? In other words, relying on string tension to provide neck relief if needed?

You guys have been really helpful so far on this.

Thank you,
pete

[MysTiK PiKn]

I can definitely feel the truss rod tighten when I turn the adjustment nut clockwise.

The clockwise direction decreases relief.

If you have high strings, high action - that would be a neck with too much relief.
If that's what it looks like, then the clockwise adjust will decrease relief, effectively decreasing the bow, the string height, and the action.

We can't see the neck.
If it's already straight, flat, no relief - a clockwise adjust will tend to induce "backbow". Very simply, the truss will pull the neck flat, and flatter, right into reverse bow.

If string tension gives you slight relief, that's likely pretty good already. Barely snug the rod so it doesn't rattle around. Don't actually tighten it Barely snug it with the strings off. Putting the strings on will slightly tighten it further by string tension.

If string tension still shows negative relief, or backbow - you are toast. - because you have no counterclockwise adjustment available.


Having said that - I'm assuming the rod is actually working in the clockwise direction. If it isn't actually doing anything, then it seems the rod is actually busted.
If that's the case, it likely needs replace.

Having said that, if it just spins freely the other way, then you should be able to insert the LONG END of the ALLEN KEY, and just easily spin it by hand effortlessly. I'm just wondering if you turn it enough, is it remotely possible that it might connect itself again.
At this point I am reallly guessing - for it to reconnect itself - I don't know if that is even a remote possiblilty.
You said earlier something was rattling around in there - that could mean the adjust went too far the other way, or something separated, or something go undone. This is way beyond my pay grade.
Maybe someone else can comment on this remote long shot possibility.

But back at the ranch - if you have good action, under string tension, you can do without the rod. Trouble is you don't have frets - so it's a case of what you might remember before you pulled the frets. So it's like Why did you pull the frets in the first place? Worn out? Extremely uneven? Neck hump. Low area at some specific location, etc etc etc ???????
.
.
That's the long answer - the short answer is yes, you MIGHT have a one-way rod = if it really is working.


Adjustments are usually done 1/8 of a turn at a time, unless you are undoing what you did before, and you know how many turns you applied.

[MysTiK PiKn]

One other thing - in between the 2 directions - it depends on the actual physical neck, channel, rod, etc.
- there might be 2 or 3 COMPLETE REVOLUTIONS before the opposite direction snugs up, and actually does something.
That's the LONG SHOT - I would like to hear that worked; but don't bet the farm on it.

and that's (partly) why I suggested using the long end of the key.

New rods are not very expensive. But I think there exciting work involved in doing the R&R. You would learn a lot if you persued it. Or - order it done.

[Rockyjohnstone]

Works only one way, clockwise. Not hearing any noise in the neck like before and not sure what that was all about. the neck will go from flat, to about .006 of relief in the middle of the neck with J-74's. This does not take into account the up bow near the nut.

I need to deal with the up bow (1/16") near in the first 3 frets. To make things more interesting, I've learned from Saga the neck is radiused 9.5' nut to 20" a the 20th fret. Seems next to impossible to do by hand. I need to think about that. Perhaps a handful of contour gauges might help. Focus on just the up bow in the first 3 frets initially, leaving the remainder of the neck radius unmolested at first. Then lightly and carefully sand the entire board trying to maintain the radius. There is a very slight hump where the board meets the body to deal with as well.

I realize this does not address the underlying issue of the neck bow, only levels the fingerboard to compensate. I might try it for sport as a temp fix.

I can't seem to get off dead center on this and want to move forward. I have a 14" x 2" x 1/8" thick piece of channel stock I'm thinking of using for a sanding block. The steel is dead flat. Anyone successfully leveled a radiused fretboard by hand? If it's doable, I'll give it a shot. If it goes awry, then I'm back to R&R the fretboard, which is sort of where I'm at now.

Seems like one or the another.

Thanks Mystic, your keepin' me engaged in this repair effort.

[MysTiK PiKn]

I'm keeping you engaged? I kinda thought you were keeping me engaged. Or maybe I'm keeping me engaged. I actually disengaged twice on this already. But that was due to lack of clear communication. So, I hear better communication now.

I'm flying blind. I can only read what you say, and accept that as accurate. This is no simple fix - this is now just a case of doing whatever seems best. And all the decisions are yours. So every stroke will count, and every stroke in just the right place will be essential. Don't ask how I learned that. You can get away with some; just know what's happening always.

So, moving right along - what are the problems? There's the illusion that a radius board is difficult. Neither of us have been there before. I used to own a guitar w an extreme radius. I liked it. I think kinda like ALMOST IGNORE the radius - but - I think it would be most useful to view it as "LINES" = the lines are defined by the imaginary strings. So, overall, the entire neck can be sanded, with the straight dead flat block; but an ongoing reference to the lines must be the rule. You aren't taking a lot of material; but are taking some material off the fb, to promote flat. And at the same time, you need to follow the lines, and blend the lines together by sanding. It will involve KNOWING what to do rather than guessing, or even thinking. Some form of consciousness of what is happening at all times. You aren't redesigning the board, just knocking out some bumps, and blending the rest. In planing you'll be working lengthwise, and moving side to side, unless there's a bump on one side.

The first thing is to set the neck to flat as possible, so bumps are more exposed. (or hollows, low spots)
You mentioned this 1/16" high spot in the area of the first 3 frets. Is it all across the width or is it just on one side? Does the neck flat position change that at all?
Also was that noticeable when the frets were still installed? Did it cause a problem? Buzz maybe? Or something else? Like high action? Or did it demand a high bridge setting? Can you describe the problem it caused?
It's likely a good idea to at least reduce that 1/16" high area - even if only down to 1/32 - or lower??? You need to know what problem that caused, and also what shape it is, and does it cross over the entire neck width?

The block sanding will perhaps outline it's true shape. Or it's extent. Eventually it will have to be blended in - and that's what a dead flat block will do for you. the Block will likely ride high over the 5th or 7th fret area - meaning it initially won't touch that 5-7 area - because of the high spot near nut. (might need to remove nut?) You can control the block with slight pressure - to FOCUS the sanding - and it depends on what grade of sandpaper you use. You need lots of sandpapers. Maybe start with 180grit and move to higher and higher grits to fine tune it. But start with very very light pressure until you can "see" some kind of pattern forming - and watch what's going on behind the block - as in the 8-12fret area.

You said the hump area was "slight" - that's good - but it probably extends back a long way. John Hamlett (sunburst) mention doing the upper extension area kinda separately, on a slight angle downwards to fade away - that area is mostly out of play area - barely used. But for planing it can fool you, and suck you in - I got caught on this when I filed my frets. So John's idea is a good one - cos the high end is out of play usually.

If you haven't already, you should looky here:
http://www.frets.com/FretsPages/Luth...5refret01.html
THE WHOLE ROUTINE is spelled out here - but you have some unique circumstances, as you know.

You basically need to follow the LINES, and take out the BUMPS. Following the lines, will preserve the RADIUS. It's not too likely that you will be sanding that much - so changing the radius is not a huge issue - but it is a consideration. caution! always caution!

Go slow and easy. Do read Fret.com LINK above. It's all there, including the entire REFRET. He uses a stripped down plane with sandpaper attached - same as a dead flat channel steel really. Check it out.

I'm being tediously repetitious; but maybe that's a good thing. I don't know what else to tell you at this point. I need more feedback from you. So let it ride, kinda like meditating on what you are planning. Take a look at the project to verify that you have a good plan. Let the picture, the movie, form in your mind - THAT will tell you how to proceed. It's the only way to know what to do. Just let it all roll around for a bit, and see what comes.

Back at you.

Later.

Peace.