Help - Right Knee Lever action

[David W.D. McCormick]

I’m fine tuning the pedal and lever action on my Carter S10. Standard 3x5 emmons copedent. Got all the pedals exactly as I want and successfully installed a tunable split (extra rod) rod on string 6.

I am having problems getting my RKR and RKL to pull the way I want - particularly the 1st string raise to G# and the 2nd string lower to C#.

I want a shorter throw on both levers. I already adjusted the pull rods as such: in the bell cranks, they’re as far as possible from the undercarriage, and at the changer, they’re as close as possible to the changer axle (they’re not at the most extreme angle possible, but close to it and I didn’t feel comfortable having them at a 40 degree angle). Then I shortened the lever travel. The problem is, once the travel is adjusted to where I want it, I need to screw in the nylon nuts so tightly to get the levers to pull to the right pitch that the open string is not returning to pitch.

Any thoughts? I feel like I’m doing something wrong but can’t figure out what. Do I need slightly longer pull rods? I’m not trying to make the throw extremely short, just short enough that I can engage it quickly.

Dave

[mtulbert]

Hi David,

Sounds like you are overtuning the guitar. You will need to increase the lever travel to get the guitar in tune. It is just the nature of the beast. What I do is tune the nylon nut without the lever engaged until the string starts to go sharp or flat depending on the change. Back off a couple of turns and then adjust the lever travel to get the pull or lower as close to pitch as you can.

You may have the shortest travel you want but this will stop the notes not coming back to pitch.

Regards,

Mark T.

[David W.D. McCormick]

Thanks for the reply Mark - I am familiar with the overturning issue - the problem is that the longest pulls (string 1&2) on the levers, which I think are the limiting factor, overtune when I set the travel the way I want it. I am considering just bending the pull rods to give more slack.

[Ian Worley]

The limitations of leverage are what they are. It's likely you're not going to get the lever action as short as you would like. The laws of physics dictate that whole-step changes on smaller diameter steel strings require long pulls on a psg. Bending the pull rods on the right knees where rods are short and angles are more extreme can sometimes help smooth out their action, but this doesn't change the fundamental leverages at play between the bell crank and the changer, which is still defined by a straight line between the two points of contact.

Something you can check that sometimes affects finger action adversely is the lower return springs. Make sure the lowering scissor is not lifting off the stop when you engage the raise on string 1, and also that the raise scissor is not lifting when you engage the full lower on string 2. Either of these could indicate incorrect tension on the lower return springs. Raise helper springs can cause issues on long pulls too, but Carters don't typically have those.

[Bobby D. Jones]

I second Mr. Worley's suggestions.

[Lee Baucum]

I second Mr. Worley's suggestions.

I third his suggestions!

[Dave Grafe]

There must be.a travel stop adjustment to limit the lever travel, you need to back it off i.e. increase the distance the lever travels before hitting the stop, then you can retune with a proper bit of slack in the works.

[Lee Baucum]

...increase the distance the lever travels before hitting the stop...

The OP wants a "shorter throw" on both knee-levers!

~Lee

[John Hyland]

If you have run out of options to increase the pull you are only left with a more complex solution . I’m not familiar with a Carter so take what I say with a grain of salt, but by adding another crossrod, bellcranks and new longer rods you can get extra leverage by having a short link between the existing bellcrank to the new. The link needs to be higher (away from the axle) on the original bellcranks and lower on the new ones. You might have to reverse one set of bellcranks if the pull is happening on the wrong side. Hope that makes sense.

[Tommy Mc]

If I understand your issue, the pull works fine if you can tolerate the longer travel. In trying to decrease the travel of the lever, you've reached the limits of the possible adjustments (other than getting a longer bell crank). I wonder if you move to a heavier gauge string for strings 1 & 2, wouldn't that decrease the amount of travel needed?

[Dave Grafe]

...increase the distance the lever travels before hitting the stop...

The OP wants a "shorter throw" on both knee-levers!

~Lee

You can't always get there from here

[Lee Baucum]

Dave, ain't that the truth!



~Lee

[David W.D. McCormick]

Thanks all for the helpful responses!

I am thinking the easiest solution is to move to a a heavier string gauge on string 1. It's currently a 0.12 and I could maybe try a 0.13.

[Bobby D. Jones]

In your first post you stated the guitar is a Carter S10.
If the guitar is light weight, The rules of Physics, May cause another problem.
Light guitars and short knee level engagements, Which take more pressure on the knee lever do not work together well. The guitar will want to waltz across the floor when the knee levers are engaged.

[David W.D. McCormick]

In your first post you stated the guitar is a Carter S10.
If the guitar is light weight, The rules of Physics, May cause another problem.
Light guitars and short knee level engagements, Which take more pressure on the knee lever do not work together well. The guitar will want to waltz across the floor when the knee levers are engaged.

Excellent point. I play on lots of small stages and don’t want to walk it right off a ledge.

After considerable thought I am (independently of this particular issue) going to try moving my e lowers to RKL. A side effect may be an easier/shorter pull because it’s only a half tone lower (?). Swapping my RKL over to LKR might give me more leverage on the whole tone raise pull which maybe gives me the feel I want (?).

[Richard Sinkler]

After considerable thought I am (independently of this particular issue) going to try moving my e lowers to RKL. A side effect may be an easier/shorter pull because it’s only a half tone lower (?). Swapping my RKL over to LKR might give me more leverage on the whole tone raise pull which maybe gives me the feel I want (?).

That should help. Keep in mind that you will still have the amount of travel issues on the left knee, but as you said, possibly more leverage with work better.