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Topic: Nut Rollers |
Stephen Williams
From:
from Wales now in Berkeley,Ca, USA
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Posted 9 Feb 2016 8:51 pm |
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After much searching I found these on ebay. I paid $3.56 for 10! and they were mailed from China.
They are 3mm x 10mm x 3mm or 1/8" thick 1/8" ID and 3/8" OD
Little bit of play between Id and OD but nothing too bad.
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 9 Feb 2016 9:18 pm
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| Correct me if I'm wrong, but aren't those grooves a bit deep - making the strings "sink into" the rollers and thereby making it impossible to roll the bar evenly on the strings over the nut? |
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Stephen Williams
From:
from Wales now in Berkeley,Ca, USA
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Posted 9 Feb 2016 9:29 pm
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You could well be right.
But why would I want to "fret" with the bar at the nut? I never have but I'm self taught so maybe I'm missing something |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 9 Feb 2016 10:11 pm
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| Stephen Williams wrote: |
| But why would I want to "fret" with the bar at the nut? I never have but I'm self taught so maybe I'm missing something |
When playing at/around the zero fret - the nut - one technique for putting the bar onto, and pull it off, the strings, is to cross the nut with the bar from/to the keyhead side. Sometimes it's done this way to achieve a "slide-on / slide-off" effect, and sometimes it is just practical. If the nut-rollers are higher than any of the strings, one definitely gets a different "effect" and will have to modify, or avoid, this "crossing the nut" technique.
Oh, and I'm mainly self-thought too ... started playing PSG 35 or so years ago and non-pedal some years before that. Doesn't limit what we can do...  |
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Jim Pitman
From:
Waterbury Ctr. VT 05677 USA
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Posted 10 Feb 2016 5:07 pm
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Actually I think you really want a V shape according to conventional guitar luthiers.
Often, the roller nuts on PSGs have V shaped grooves of varying depths to match the specific string guage such that the top of the strings lye in the same plane to prevent buzzing when you are barring at fret one....phew that was a long sentence.
Even though my Infinity PSG doesn't use bearings in the rollers it has addressed the stiction in another manner. The axle is a mere 1/16" in diameter. The rollers are big as rollers go, 3/8". In this manner the mechanical avantage has been increased and the friction reduced due to the bigger radius and reduced contact surface area of the smaller axle. The net effect is I have zero hysteresis on a keyed guitar. |
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chris ivey
From:
california (deceased)
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Posted 10 Feb 2016 8:49 pm
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| i wanted an infinity. how's the cabinet drop? |
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Ron Pruter
From:
Arizona, USA
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Posted 10 Feb 2016 9:37 pm
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I want to address my stiction so I too, can have zero
hysteresis. Seriously though, I've always felt by making an axle smaller, true, there is less contact area but that smaller area is taking more pressure per
allotted area, canceling out any advantage of less contact.
Comprende??? RP
_________________
Emmons SKH Le Grande, '73 Fender P/J bass, Tick tack bass, Regal high strung, USA Nashville 112. |
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Jerry Overstreet
From:
Louisville Ky
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Posted 10 Feb 2016 9:49 pm
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Stephen, those look good to me and a bargain too boot. Are they made from steel? Far as the groove, they look very similar to the Mullen nut roller grooves and appear to be about the same O.D.
FWIW, I don't roll my bar off the nut either and I'm not self taught. I do bar bounces, hammers or just pick it up.
I'm interested to hear how they work out for you. I think the guitars I've owned do have a smaller axle..about 1/6" v. the 1/8" I.D. of those.
I'm curious to know if that's an issue on your guitar and if you have to fab an axle to fit both the keyhead and your new rollers. Even that shouldn't be all that difficult.
Good luck. |
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Jim Pitman
From:
Waterbury Ctr. VT 05677 USA
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Posted 11 Feb 2016 3:28 am
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Chris, my Infinity has less cabinet drop than my other single 12 guitar, but, it may not be a fair comparison. My other S12 is a double wide cabinet whereas the Infinity is single wide.
Ron, whenever I deabate a physics question I exagerate the conditions. Imagine a roller nut that's 1" in diameter with a 0.9" axle going through it. = quite a more friction due to increased surface contact area, and alot less mechanical advantage at the point of contact where it must overcome the friction. |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 11 Feb 2016 8:53 am
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Strings are pushing down - albeit at an angle - on the nut rollers. Thus, by increasing clearance between roller's ID and axle's OD slightly, the "pressure-point" becomes very narrow.
As example of a very low friction nut roller, here's an idea-sketch from my own PSG project: the "Pacman roller" - steel pacman-styled rollers on knife-edges...
Roller OD: approx 7/8 in. (same as my bars)
Max string "travel" +/- 1/8 in. My design is for a "keyhead changer" that has all the string travel at/near the nut rollers and therefore must rotate quite a bit ... unlike for a regular "bridge changer", that has very little string travel at the keyhead end and therefore very little rotation of the nut rollers.
So far my "Pacman" roller is just a well-tested idea for my own PSG project. It works perfect - no hysteresis, but I have no plans for adding it to my regular PSGs since it is difficult to make to fit on those.
Back to the conventional nut-rollers on a regular "bridge changer" PSG: friction for the nut-rollers has to be kept at a minimum because "pull-force" gets lost along the length of the strings for that very small degree of nut-roller rotation. Any hang on the nut will cause slight detuning of the strings after a raise or lower.
Unless the roller gets "glued" to the axle because the tolerance is too tight and dried-out oil fills the gap, a conventional roller with large OD and small ID will ride almost frictionless on top of its axle.
My conclusion: ball bearings at the nut is overkill on regular "bridge changer" PSGs because of the small degree of rotation for the nut-roller. Large OD, small ID, rollers on an ever so slightly under-sized axle will reduce friction to an insignificant amount. |
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Jerry Overstreet
From:
Louisville Ky
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Posted 11 Feb 2016 8:57 am
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Well, maybe some people consider it overkill and some don't. Depends on the situation. At this price, it's certainly worth a try and I don't see how it could possibly hurt anything.
I'm really interested in Stephen's conclusions. |
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Ian Rae
From:
Redditch, England
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Posted 11 Feb 2016 1:11 pm
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This is my nutless tuner, which is really a miniature pull-release changer. No hysteresis, no flexing, no backlash, no vibrating spare length - nothing happens at this end of the guitar at all!
I don't use the open strings a great deal, but it's nice to able to slide on and off seamlessly.
_________________
Make sleeping dogs tell the truth!
Homebuilt keyless U12 7x5, Excel keyless U12 8x8, Williams keyless U12 7x8, Telonics rack and 15" cabs |
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Stephen Williams
From:
from Wales now in Berkeley,Ca, USA
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Posted 11 Feb 2016 4:34 pm
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I have some solid rollers which I think i can temporarily replace with these so i shall compare.
I actually bought these for a different purpose. I saw how they could be good nut rollers so that's why i posted. when i searched awhile ago they were so expensive.
The different purpose is it's going to be part of the lower finger on my double-ended changer. The lower finger is at the left end and i will be keeping a keyhead because i like the way they look.
The red part is the wheel. This part may be TUSQ which is impregnated with slippery PTFE. I will experiment. The problem with the wheel is holding it in place. I can't find any channel or clevis that is 5/16" wide |
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Stephen Williams
From:
from Wales now in Berkeley,Ca, USA
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Posted 11 Feb 2016 5:01 pm
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| Jerry, yes they are steel. I have been trying to locate parts off-the-shelf for PSG because a machine shop is not an option. |
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Brendan Mitchell
From:
Melbourne Australia
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Posted 12 Feb 2016 3:27 pm
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| Hey Stephen could you point us to an eBay link for those rollers ? |
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Stephen Williams
From:
from Wales now in Berkeley,Ca, USA
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Jerry Overstreet
From:
Louisville Ky
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Posted 12 Feb 2016 6:31 pm
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Well, now that I see the zoomed in view, the groove does look deeper, more like a pulley groove than what I first thought Georg, so I don't know. Might still be workable as nut rollers though. Have to hold one in my hand to tell.
Stephen, please keep us posted on how they work for your application at the fingers if you would. |
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Brendan Mitchell
From:
Melbourne Australia
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Posted 14 Feb 2016 1:48 am
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| Thank you Stephen |
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Chris Templeton
From:
The Green Mountain State
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Posted 14 Feb 2016 4:29 pm
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When I spent time with Ned Steinberger, he often spoke of the knife edge roller nut. He has used that nut design with his tremolo and Transtrem systems.
I've always wanted to see a steel changer that uses the knife edge design.
_________________
Excel 3/4 Pedal With An 8 String Hawaiian Neck, Sierra Tapper (10 string with a raised fretboard to fret with fingers), Single neck Fessenden 3/5
"The Tapper" : https://christophertempleton.bandcamp.com/album/the-tapper
Soundcloud Playlist: https://soundcloud.com/bluespruce8: |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 14 Feb 2016 4:46 pm
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| Chris Templeton wrote: |
| I've always wanted to see a steel changer that uses the knife edge design. |
For now I can only show you a sketch...
...of my knife-edge based keyhead changer design. Maybe I'll get around to build the contraption one day |
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Chris Templeton
From:
The Green Mountain State
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Pat Chong
From:
New Mexico, USA
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Posted 14 Feb 2016 6:34 pm Pac-Man rollers and bearings.
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Hello Georg,
I was looking at the design. First, it looks cool, and I understand the principle. But there is one thing I wanted to know though:
1) How are you going to keep the "pac-man" rollers centered? For example, just replacing and tuning the strings on the guitar would take the bearings to one edge (counter-clockwise) and not allow for smooth movement and hang up the roller. Would you use some sort of "centering" tool to align the rollers, after tuning?
2) Another possible problem would be vibration (someone knocks into the head, or the unit falls over, etc.), messing up the alignment of the pac-man rollers, again, restricting movement.
I thought maybe you have a solution.................
.........Pat |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 14 Feb 2016 7:13 pm
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Pat, basically, those rollers will self-center after a couple of raises and lowers after it is tuned up, because the strings will slip over the rollers until there's no more resistance. The shallow string-angle - about 7 degrees, and the fact that the string-pulls/-releases are over the short distance from the moving tuning mechanisms, ensures that this "self-centering" works as intended.
That simple drawing also do not show the details/parts that will keep rollers and other moving parts in place and aligned - with or without strings on the instrument.
That initial idea-sketch is about five years old now, made only so I could keep my own thought-process on track. I hope no-one find it strange that I keep the pretty detailed 2D and 3D drawings of a functional design I have made in later years, to myself for the time being. |
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Stephen Williams
From:
from Wales now in Berkeley,Ca, USA
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Posted 14 Feb 2016 8:56 pm
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Georg, would you use the pacman-nut at the changer end also? i've always thought that would be simple because the fingers are then simpler.
Only thing i don't know is how that would sound vs integral finger (strings pass over finger as a bridge).
First PSG I built was individual rollers for a bridge and aluminium channel as a pull release finger. Very simple . It worked but sounded a bit naff i think because too much thin aluminium. |
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Pat Chong
From:
New Mexico, USA
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Posted 14 Feb 2016 9:15 pm 10-4.
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George,
Yo comprendo! Simple and practical, too.
.............Pat |
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