Roller nut question

Mac Knowles · From: Almonte,Ontario, Canada

After the great discussion we had recently here on the subject of parallax on the fretboards here’s another question I’d like to throw out at you folks for opinions.
My first steel I built in 1962, a double with 10 strings on E9th and 12 on C6th with 8/4. A simple mechanism with the old pull/release changer. I gigged pretty steady with that guitar for nearly 30 years with not a lot of problems or maintenance. Awhile ago since I don’t use it much anymore I thought I’d give it an overhaul. Among other things I thought I’d make a new set of gauged rollers for the peghead end. As I’m thinkin’ about making 22 little brass rollers on my old lathe, I’m lookin’ at about 30 guitars hanging on the wall in my shop….none with a roller nut. I’m thinking why do I need this contraption there anyway, why not just a nice round brass rod of maybe 1/4” diameter or so with gauged string slots in it, supported all the way across a new solid peghead end. All the pulling is at the other end, can’t see what difference it would make whether the string slides over a fixed nut or one that turns. Might even improve the tone and sustain with a more solid connection to the rest of the neck and body. To heck with tradition, opinions anybody?

Cheers,
Mac

James Martin (U.K.) · From: Watford, Herts, United Kingdom * R.I.P.

Good point, Mac. I'm interested. All traditional ideas should be challenged from time to time as technology moves on and new concepts surface from inventors and innovators such as yourself. Can't help thinking, mind you, that this has been brought up in the past !!

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Robert Harper · From: Alabama, USA

Doesn't the roller at the end of the guitaar roll miniscully as the string is flexed one or the other way? If it doesn't roll where does the stress go (pressure)?

Mac Knowles · From: Almonte,Ontario, Canada

I imagine way back this subject has been brought up. And true, probably the nut rollers do move a tiny bit with the raises and lowers. I'm guessing that the string would just slide that bit, just the way it does when you tune with the machine head. Not having the roller nut there would probably change the characteristics of the portion of the string that's beyond the nut a bit too. Anyway I'm going to try it and see. This guitar has always been a bit hard on strings as it has (had) a 25-1/4" scale length. I'll see if it makes a difference.

Mac

Don Sulesky · From: Citrus County, FL, Orig. from MA & NH

On a keyless head they move less or not at all which to me would reduce the lenght of the pedal & knee throw. Why not go as far as they do on standard guitars and lock the strings at the nut and restrict the stretching to none at all. I think it would eliminate the hysterisis problem completely.
Don

Danny James · From: Summerfield Florida USA

This subject has been discussed before, but I will try to shed some light on your question as to what difference a roller nut makes. I hope others chime in too.

Without roller nuts when you depress a pedal and raise or lower a string the friction at the nut will keep the string from returning all the way to pitch.

The rollers do move a very insignificant amount however it is enough to make a considerable difference as to whether your guitar stays in tune.

I made a gauged roller nut for the lap steel guitar that I built, because it has a tuning changer in it.

I turned gauged brass rollers in my lathe. I simply started with short pieces of each string. I cut a shallow groove (60 deg. included angle) in a roller for that piece of the first string to lay in. I measured with a micrometer the distance from the opposite side of the roller to the other side with that piece of string lying in the groove. ( be sure a little bit of that string is still above the roller) I wrote that reading down. For my second roller I did the same thing with the second string, but used the same micrometer reading as I had on the first string roller. I did this using the same micrometer reading each time for each consecutive roller & string. The grooves automatically get deeper for each string. When it was done the bar side of all strings was on the same plane. This way is simple, and it doesn't require a lot of mathematical calculations. I get no rattles at the first fret. It works for me. Very Happy

David Doggett · Posted 31 Jul 2007 8:28 am

As Don says, on a keyless head, you might be able to get by without rollers. With a keyed head there is enough stretch required behind the nut to cause problems without rollers. I had an early Maverick without rollers. There were V-shaped grooves cut in the end of the keyhead block. The strings made a scratchy sound when pedals or levers were used. I didn't notice any strings not returning fully, but I wasn't very carefull about tuning back then, and didn't have a chromatic meter to check things. When I replaced the key head with one with rollers, the scratchy sounds dissappeared. Also, it seemed like it was easier to tune more precisely. Without rollers, the strings tend to catch at a certain point while tuning. You have to keep turning the tuner with no effect until suddenly the string jumps past its sticking point and is then out of tune in the other direction. Also, the sustain improved drastically. At some point all pedal steel manufacturers started using rollers. They're probably not all wrong.

Justin Brown · From: Chicago, Illinois, USA

What about just locking the strings down at the nut, Floyd Rose-stye? I guess that would make tuning more complicated, but you wouldn't need the rollers.

Brint Hannay · From: Maryland, USA

The GFI keyless has no rollers, just a cylindrical bar nut.

Danny James · From: Summerfield Florida USA

I can see where if you had a keyless tuning head that there may be no need for a roller nut. I would think it would make a difference as to how close the nut was to the tuning mechanism. The closer the better.

On the traditional tuning heads where there is quite a bit of distance between the nut and the keyed head, there is some string stretch involved. Thats where a drag/friction problem arises.

A lot of people prefer the looks of a guitar with a traditional keyed head on it. I guess I'm one of them. Smile

However, I like what Mac Knowles says " to heck with tradition". Very Happy

It's always interesting to see where someone has experimented and came up with something new that really works. Very Happy

Good luck on your project Mac. Let us know how it all comes out. I think on your guitar with the keyed head, you will like the roller nut. Idea

Kevin Hatton · From: Buffalo, N.Y.

Hysterisis.

Robert Harper · From: Alabama, USA

Someting women have they change

Mac Knowles · From: Almonte,Ontario, Canada

Thanks for all the opinions and info. The guitar I was talking about had rollers to begin with. I made them out of some copper electrical splicing hollow rods. Mind you that guitar cost me less than $50.00 to build in 1962. Made all the parts with basically a cheap scrollsaw, a 1/4" drill, a few files.....and lots of time. All the aluminum was free from where I worked, and the maple came from our own woods. The rollers were all pretty well seized up and ratty after so many years of playin’ on it.

Think I’m going to try the ¼” bar nut first though. See what happens. Seems to me the actual contact surface on the ¼” bar where the string hits it is going to be pretty small. Might bind there but might not either especially with a spot of graphite or oil on that spot.

Cheers,
Mac

Robert Harper · From: Alabama, USA

I wonder what a wooden rooler would sound like or hardened palstic. Just thinking outside the box

Bill Ford · From: Graniteville SC Aiken

The non roller keyhead[like the first Sho-Buds]had a tendency not to return to pitch when a pedal was depressed. The first PSG that I had was like this, I kept a small container of 3 in 1 oil handy and when it started to detune, I would put a drop on the strings at the bridge, worked OK till it dried out again.Non keyless PSG guitars work better with rollers.

BF
_________________
Bill Ford S12 CLR, S12 Lamar keyless, Misc amps&toys Sharp Covers
Steeling for Jesus now!!!

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Every single (keyed) pedal steel made in the world today has a roller nut.

I guess they just use them for looks? Rolling Eyes

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Every single (keyed) pedal steel made in the world today uses a roller nut.

I guess...they just use them for looks? Rolling Eyes

Mac Knowles · From: Almonte,Ontario, Canada

Donny....I'll let you know how it works out!

And I don't really particularly care if there's another one like it anywhere else on the planet.

Mac

David Collins · From: Madison, North Carolina, USA

Got an old, old Marlen. No rollers on the nut. It does suffer slightly from hysterisis, but IT DOES SOUND GOOD!

_________________
David Collins
www.chjoyce.com

Billy Carr · From: Seminary, Mississippi, USA (deceased)

Looks to me like the strings, especially the 3rd wouldn't last very long or stay in tune without the roller nuts. Ringing strings might be a problem also w/o roller nuts. Looks like the string would have a wear spot on it where it goes over to bridge to the keyhead. The major problem that I've found on guitars, even a few new ones is when a roller nut is stuck and won't move. I check each one and keep them oiled to prevent problems.

Mac Knowles · From: Almonte,Ontario, Canada

Interesting picture of the keyhead on the old Marlen.
Not exactly what I had in mind. I can see that the strings are travelling over a rather long flat area before going to the tuners. I would suspect that friction would come into effect there giving problems. What I had in mind was a 1/4" rod with minimum slots in the top. The actual area that the string would touch on the round rod would be very small. In fact without any slot at all the area where the string touched the rod would be miniscule, but would depend on the angle that the string took after going over it on the tuner end. Strings 5 & 6 would be the least and 1 & 10 would be the greatest angle. Just seemed to me that eliminating the roller and axle would make one less part for the string vibration to pass through and possibly increase the tone or sustain or something (?)

Interesting how we can get into these great technical discussions on the pros and cons of some small part of these silly instruments. Like I said earlier I think I'll try it anyway. If it doesn't work or sounds crappy I'll make the new rollers and move on to enjoying the great summer weather. Not a big deal in any case. I pretty much only build guitars with the double changer now. Raises on the right and lowers on the keyhead end. Man did I spend a lot of time and effort drawing pictures and making test parts before I got what I was looking for. But that's what I like to do.........perhaps even more than playing the stupid thing (according to the Queen of the realm anyway).

Thanks guys,

Mac

Alan Brookes · From: Brummy living in Southern California

I would never build any sort of string instrument without roller nuts and bridges. When you tighten a string at the machine head you increase the tension between the machine head and the nut. A fixed nut holds onto the string. Then when you're playing the tension will equalize throwing the instrument out of tune. It will equalize only down to the bridge, which also holds the string. The next equalization takes place between the bridge and the string anchor, throwing it out of tune again. If you have a tremolo arm, every time you use it you create the same equalization problem. With a pedal steel guitar you can multiply that problem over and over again every time you work a pedal or a knee lever. Without roller bridges a pedal steel would never be in tune.

Mickey Lawson · From: Cleveland, Tennessee, USA

What would happen if you had two sets of rollers. Tuning keys would be about one inch further to the left of the nut. And, the second shaft w/rollers would be 1/2 inch to the left of the nut rollers and at 45 deg. angle. Strings would go over the nut rollers, and under the second rollers (more equally distributing the hysteresis). Ah, just a stupid thought.

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

Although the string stretching isn't always as serious on a guitar, when a guitarist using light gauge strings does serious bending, the string(s) can move quite a bit in the nut slot(s) and there can be pretty serious hysteresis problems. So guitar players and designers have also been wrestling with a version of this problem for a long time.

One of many guitar solutions - but not the only one - has been something like bearing roller-nuts (there is a good one made by Wilkinson), and also roller-bridges (they come on some of the newer Gretsches and some other guitars). The roller bearings are on the side in the Wilkinson roller-nut. I put one on a solid-body guitar several years back. It worked very well, with no noticable negative sustain effect. But to my ears, it changed the tone and feel of the guitar enough to decide it wasn't for me.

Another very popular solution in the 80s was the locking nut - most commonly seen in Floyd Rose tremelo and locking-nut system. I can't tell you how many nice old Strats I've seen that had the top of their fingerboard and above hacked up with locking nuts. Evil or Very Mad

These became largely unpopular with most guitarists, but still are widely used among whammy-wielding shredders. I'm sort of surprised that - apparently - nobody has attempted to put a locking-nut system on a PSG - it makes all kinds of sense from this point of view. Of course, there would need to be some kind of system to level the strings - if they were all clamped down to a truly rigid and level take-off point, I expect there might be bar-to-string chattering, especially on C6 or universal.

But still - most guitar players don't like any of this stuff, and still use conventional nuts made of bone or some hard synthetic material. I've tried the roller nuts and bridges - for a certain sound, they're great - but except on certain styles of guitars like a big Gretsch archtop, I find they interfere with sustain or change the tone a bit. I don't like them on most solid-body guitars, and I bend strings a lot on these.

The hysteresis problem with non-roller nuts is purely friction. If one can make a very hard and smooth nut, and perhaps lube it somehow, it might be possible to make it work without rollers. One guitar solution is a nut made of graphite - it works pretty well and plenty of whammy-bar oriented players who don't like Floyds use them. I'm not sure it would sound good on PSG, though. The nuts on my guitars are generally made of the traditional bone material - I have a fine luthier make and set them up very carefully, and I use some type of Teflon-lube in the slots. If it's properly set up and lubed, I rarely have hysteresis issues, even with heavy bending, changing tunings, or when I was using a B-bender.

For pedal steel, perhaps the issue is material and finishing choice. I'm not a metallurgist, so I'm not sure what the best choice would be. Just a very hard metal which can be machined properly and then polished very well. Or perhaps something like the hard chroming process that Bill Stroud uses that makes his bars glide so freely over strings would help. I think it's an interesting problem.

I had a late 50's Gretsch Tennessean model 6119 with Bigsby - these are known for tuning stability problems without a roller bridge when using anything but a light vibrato. But the stock bridge was just a big fixed round bar with highly polished chrome. It had no intonation compensation at all, just a straight bar - unless you had a wound third on there, there were some intonation problems. But that guitar had the best pitch stability of any Gretsch I've ever played. Those strings just glided back and forth on that bridge with no problems at all, no matter what I did to the Bigsby. I always popped a little Teflon-lub in the grooves whenever I changed strings to keep it slick. I dunno - just because nobody's ever achieved a solution doesn't mean there isn't one.

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