Whole step on 1st string

[Danny Smith]

I recently bought a Derby SD10 and love it.

But I need to change the knee lever for the 1st string to pull a whole step instead of a half. Is this something I could change myself or should I find a steel mechanic?

[Tucker Jackson]

Hi, Danny. You can probably do it yourself.

What you're trying to achieve is more leverage when you push that knee lever. So, in short, you get that by simply moving the pull rod to a different slot on the bellcrank.

1) Document things so you can put it back if you mess it up.

If you don't have a fancy guitar-holder on your workbench, flip the guitar over in the case and work that knee lever by hand. Locate the moving bellcrank that's attached to the long pull rod that runs down to the the 1st-string section in the changer. Write down which slot or hole in the bellcrank the pull rod is currently attached to. Later, you're going to be moving this pull rod to a different location on the bellcrank.

2) I don't know how your rods attach to the bellcranks -- but on some guitars, to disconnect a rod, you would first need to unscrew the nylon tuning nut at the other end of the rod and remove it so you can pull that rod through the changer a little. Note which hole in the changer it is currently using so you can put it back there should the rod come out of that hole.

3) With the guitar upside down in the case, detach the 1st string's pull rod from the bellcrank. You'll then want to reattach it and select a hole or slot that's further away from the bottom deck of the guitar. I don't know whether you should try 1 or 2 notches above where it currently is sitting, so this might be trial and error. I would start with 2 notches. And as part of the reattachment process, first, be sure the other end of the rod is poked through the correct hole in the changer. Then, and only then, can you proceed and connect to the bellcrank.

4) Put the nylon nut back on and tune the 1st string raise. After you have it properly tuned, check to make sure that, at neutral, there is a slight amount of slack with that pull rod -- the nylon nut should NOT be very tight against the changer, there should be a tiny bit of 'play' such that you can push it in and pull it out a little with your fingers, just like the other nuts.

5) I mentioned trial and error: if you can't get it up to pitch, not without over tightening the tuning nut (thereby losing that tiny bit of free 'play'), you need to select a different slot on the bellcrank (one even further from the bottom deck). Or, if you're already at the top and out of bellcrank slots, select a different hole in the changer (one closer to the bottom deck of the guitar).

[Bengt Erlandsen]

It could be as easy as adjusting a stop screw on the knee lever itself in order to let the knee lever travel a little further. There could also be a stop screw for the return of the lever.

Try engaging the knee lever and tune the nylon tuner so string reach G#
Release lever and see if it go back to F#. If it return sharp then the return stop screw underneath will need to be backed out enough until there is a little bit of slack between nylontuner and raise finger.

A picture of the underside of the guitar would be of much help to figure easiest way of getting taht full step raise.

It should be fairly easy to fix and definitly something you can do yourself.

B.Erlandsen

[Danny Smith]

Thank you Tucker and Bengt for the detailed (and quick) answers! I don't know the names and locations of the parts you mention but will try to figure it out. I'm fairly mechanical, so adjusting things shouldn't be a problem, assuming I can find the right parts.

Here are some pictures of the RKR lever.

[Bengt Erlandsen]

If you follow your RKR lever towards the little gray roller that touch the L shaped brakcet connected to the cross-shaft with two pullrods, one of them for the 1st string. You will see a small set screw just before the roller. I think that set-screw controls your return stop on the lever. You might need to back this screw out a little if you need more lever travel.
The engaged stop seems to be a physical stop w no adjustment screw.

Both pullrods are already at the holes furthest from the cross-shaft so they cannot be moved further away to increase how much the pullrod moves when lever is engaged.

It might be possible to relocate the pullrod to a different hole at the changer but it is difficult to tell without a picture of the endplate showing the nylon tuners location.


BTW, your 2nd string seems to be overtuned just a little, meaning there is no slack between the nylontuner and the lowering finger when RKL is at rest. I can see a set-screw shown on the first picture that controls the stopping point when you engage the RKL lever. There could also be a setscrew for the return stop somewhere in between there but I cant see one in the pictures. Either way, your RKL needs a little more travel from "not engaged" to "engaged" in order to get some slack on that nylon tuner for the 2nd string.
If the set-screw for the engaged stop is the only one there, then this screw need be backed out a little and also back out the nylon tuners lower on strings 2 and 9 as these will now lower further below what they previously did.

The mechanics of this guitar seems to be a breeze to work on. If you work on one thing at a time it should be fairly easy to figure what each part do and make the necessary adjustments by yourself.

B.Erlandsen
Zumsteel S12extE9 7+7

[Danny Smith]

Thanks Bengt. I understand what you're saying. I will try to adjust the set screw, or if that doesn't work, try to move the rod to a new changer slot.

Regarding the 2nd string, what effect does overtuning have on the guitar? In other words, why is the slack necessary?

[Bill Moore]

I raise the 1st string a whole step on my Derby. The rod on your guitar is set up exactly like mine. You don't need to change it, just adjust the lever travel as needed.

[Bengt Erlandsen]

Any adjustment of an overtuned nylon tuner will also affect the open string. Retuning the open string will then throw the note that the pullrod is controlling out of tune and you have to readjust the nylon tuner again and you are in an endless loop of trying to get both the pull and the open note in tune.

I would try backing out the (2nd string) nylon tuner until there a little bit of slack between the nylon tuner and the lowering finger, then retune the open string to D# since it will now be sharp because the lowering finger has returned to its natural resting point.

The pull from D# to C# should still be intact since only thing that has changed is the starting point of when it starts to lower.

The overtuning could have happened trying to match up the 9th string lower to act as a halfstop feel when 2nd string reach the D note.
If so, then the nylontuner on the 9th string has to be adjusted as well. It is essential that both the 9th string and the 2nd string lower their notes at the same rate in order to get this halfstop feel point at the correct place.

B.Erlandsen

[Bob Carlucci]

a lot has to do with how much slack is in that change right now.. Over the years, I have had several guitars that all I needed to do was simply screw the nylon tuner in a little more to go from G to G#.. No stop adjustment needed, and nothing ever out of tune.
Other times I have had to move the lever stop a little bit to get a little more pull.. The entire procedure no matter how you do it should be a 10 minute job, max... bob

[Danny Smith]

I was able to get this resolved.

It took nearly all of the suggestions to get it done, so thanks to everyone who commented.

1. The stop screw moved it some, but not to a whole step
2. Moving the pushrod to the top changer slot got me close, but still no wholestep
3. What finally got me there was adjusting the pushrod itself in the Bellcrank to get a little more pull distance.

I also found that the previous owner must have adjusted the lever stop set screw alot. If I had realized this first, I might not have needed to adjust the pushrods. Live and learn, I guess. It works pretty well now.

[K Maul]

I was able to get this resolved.

It took nearly all of the suggestions to get it done, so thanks to everyone who commented……
Live and learn, I guess. It works pretty well now.

Yes, that’s how it’s done. Welcome to the Rabbit Hole. Try to restrain yourself from tinkering too much, as I have NOT been able to do.