Aluminium fingers?

[Stephen Williams]

I am imagining the strings might cut into the fingers after a while. is that a problem though? Will steel fingers sound better?

I only ask because i might just be able to fashion a finger from Al but 'twill be difficult in steel.

[John Billings]

Well,,,, try bronze.

[Ian Rae]

Alumin(i)um is not a very musical substance, and although being softer it seems easier to work, it clogs files and grinding wheels. Steel takes longer but gives a neater result and sounds good. My first step in construction was to fashion this by hand



Once I knew I could do that, the rest was easy, or at least easier! (In the pic you can see the string pin about to be trimmed off.)

[Bobby Burns]

Some aluminum sounds better than others. The standard for steel guitar parts is 6061-T6, which is machinable and weldable, and tempered. it sounds very good (most steels you've heard). Most of the stuff from the home stores and such is too soft to sound good, and doesn't machine cleanly. Search for 6061-T6 online and you'll find lot's of sizes, at similar prices to the crappy stuff in the stores.

[Ross Shafer]

As Bobby's post informs, all aluminum alloys (this goes for steel too) are not created equal. Material hardness is the main property to look at when considering finger wear from string pressure. And that varies amongst the various alloys and the heat treatment level of the materials has an impact on the hardness as well.

6061t6 while hard enough to work pretty well for steel guitar fingers is still softer than mild steel. Other aluminum alloys like 2024 or 7075 (depending on heat treatment level) can be just as hard or harder than mild steel.

The harder aluminum alloys are not gummy like softer alloys and are a joy to machine. Other types of processing like forming and bending are another another story, but that's not part of the current discussion.

As far as what sounds better.....that's an individual preference and really cannot be determined without very tightly controlled testing, where everything other than the finger material is identical in every way (tightening torque on every fastener in the structure included) to isolate the difference in material. In a wood bodied structure, it would be virtually impossible to determine the sonic difference in finger material without using the fingers in the same guitar (pretty easy to do if one has the different fingers to compare).....all pieces of wood are different from one another, even from the same tree.

[Ian Worley]

Have you spent much time on the Steel Guitar Builders forum Stephen? http://steelguitarbuilder.com/forum/index.php. They've been discussing this sort of stuff in great detail for a long time. You might find some really good insight to help you along over there.

Ian Rae's project thread here on SGF is really cool too if you haven't been following it: http://bb.steelguitarforum.com/viewtopi ... 64#2243264. A lot of good advice relating to practical planning and prototyping, not getting ahead of yourself in the process.

Hardness and density are the determinants of how a material conducts vibration. Intuition would say that a hard material like chromoly would be best for solid conductivity of musical vibrations of a string, but aluminum would be the easiest to work with in the average home shop. As Ian points out, aluminum has other issues to consider, so mild steel is probably a very good choice for a home build with limited machining resources (just keep it oiled!).

Good luck!

[Ian Rae]

Ross, thanks for the education about those harder alloys. I am tempted to try one of them, but two things occur to me. One is whether density matters - I find the weight of my all-steel changer reassuring, not punitive; and secondly what lubricant would one use on the axle, which presumably still has to be steel?

[John Billings]

"it clogs files and grinding wheels."

Old machinist trick. Get a block of that blue chalk from the hardware store and rub it across your file. I fills the spaces between the teeth and the filings just fall off. There's a cleaning stone for grinding wheels. You just press it against the wheel, and it cleans and dresses the wheel.
I've thought that Bronze or Bell Bronze might be interesting to try. It is considered a very musical metal.
https://en.wikipedia.org/wiki/Bell_metal

"Bronze also has very low metal-on-metal friction, making it invaluable for the building of cannon where iron cannonballs would otherwise stick in the barrel.[22] It is still widely used today for springs, bearings, bushings, automobile transmission pilot bearings, and similar fittings, and is particularly common in the bearings of small electric motors. Phosphor bronze is particularly suited to precision-grade bearings and springs. It is also used in guitar and piano strings."

https://en.wikipedia.org/wiki/Bronze

Had a discussion with Bent Rommes about this some time back. I think he's tried bronze.

[Donny Hinson]

Ross, thanks for the education about those harder alloys. I am tempted to try one of them, but two things occur to me. One is whether density matters - I find the weight of my all-steel changer reassuring, not punitive; and secondly what lubricant would one use on the axle, which presumably still has to be steel?

Density (mass) and hardness certainly matter, but since changers have already been made from both steel and aluminum, either will definitely work. There will be differences in tone and sustain, but you'll never know exactly how it will sound until it's built and mounted. A lot of a steels "character" comes from the body material, and from the way the changer is mounted.

As far as lubricants, most will probably work acceptably because the actual movement of parts in a pedal steel is so little, and the forces are not excessive. Plain oil works well with both steel and aluminum, which are found working together in almost every automobile engine.

[Ian Rae]

I should have thought of what Donny says about car engines. I may well give Al a go at some point. I might even like it!

[Ross Shafer]

No doubt density plays a role in tone....how much? Heck, I don't know. As has already been said, the tone will be influenced by the entire structure, the player's technique, the pickup, the cables, the amp, humidity, air density and of course ears....dang a bad hay fever day can play hell with my ability to dial things in tone wise.

One little factor like finger material density is just one little bit of a pretty large equation. I made Phosphor Bronze (super expensive and difficult to work with material!!) fingers to replace some 6061 fingers in a steel guitar a couple of years back. The difference in tone was subtle at most and not very noticeable.

As far as lube is concerned for aluminum fingers, Donny is right its not a problem....even if there were a lot more movement, given proper oiling it works just peachy. The steel cams in my all three of my motorcycles run in aluminum heads with no bearing material between the journals in the heads and the cam. Yes I know the revolution speed of the cams allows a true oil film layer for the cam to spin in. Not necessarily the case on a low speed, high point pressure situation like a steel guitar finger, but still not a problem given proper mfg. clearances, assembly and maintenance.

You've actually got a much worse wear issue using mild steel fingers on a steel shaft if its not significantly harder than the fingers. Rubbing, sliding, turning similar metals against one another with a bit of pressure (even with oil between them) can cause galling. If using steel or stainless steel fingers, its important to use a shaft that has a significantly harder surface.

[Stephen Williams]

Great information....thanks. I can build the body and compare an Al finger to a steel one.

[Ian Rae]

Thank you Stephen for opening such a nourishing can of worms - it's got most interesting!

Ross, I'm aware of some of the difficulties with dissimilar metals, but it hadn't occurred to me that the same metal bearing on itself could cause a problem! I have mild steel fingers on a mild steel shaft. I'm about to dismantle them (to alter the string spacing) so I may be able to see if there's been any transfer of material. It could be that the process of drawing the round shaft hardens the surface enough to differentiate it from the fingers, which are of black (rolled) stock and maybe a little softer.

A quick thought outside the box - is the best finger material for a 0.011" G# string also the best for its big fat brother two octaves below? Do they all have to be made of the same stuff? Perhaps not.

[Stephen Williams]

Outside the box it is then.

Can we imagine a society where art and music were actually supported as part of our human legacy? These questions would be answered or attempted to be answered by the University of PedalSteelia. What we have is a lauding of making money where 1959 Les Pauls sell for $400,000 and sit languid in the stockbrokers' den.

if you're not for this, you're for "them" ha ha

[Ian Rae]

Ok, so here's some evidence of the galling that Ross warned about. The fingers are made of hot-rolled mild steel and the axle, although cold drawn, is clearly no harder.



For the new axle I am going to try a piece of CZ121 brass. The quoted hardness values of the steel and brass overlap somewhat, but the brass is probably a bit harder and I'm hoping the dissimilarity will help. In any case I believe that brass is generally a better bearing material. I would invest in phosphor bronze if it were known to be significantly harder, but the only quoted values I can find go from 80-225 HB, which is unhelpful (the steel is around 130).

[Martin Weenick]

I use 6061 aluminum for all my steel parts except the cross shafts and the top part of the fingers. For that I use 7075 aluminum which is about the same hardness as light steel. the raise and lower bars on the fingers I make out of stainless steel. Martin.

[Sonny Jenkins]

McMaster-Carr sells what is called ejector pins that are very hard and polished to precision,,,not much more expensive than other materials. Need to be cut with abrasive disc,,,,VERY good for shafts
http://www.mcmaster.com/#ejector-pins/=z7ytav

[Ian Rae]

Thanks Martin and Sonny for those tips. Those pins I discover are three times harder than mild steel or 7075 Al, which I shall try when I can find some in a suitable size. My usual supplier has it, but in a massive log a foot thick! He offered me a slice, but that would leave me a lot of machining...

[Stephen Williams]

Was thinking of the 7075 Al also. pretty expensive.

Ian how did you get the top of the finger into a semicircle?

I had an idea to clamp a dremel to a tabletop with circular sawblade perp. to table top. Drill hole in tabletop for axle and drill hole in finger and place over axle.Feed the finger (a piece of say 1" x 1/4" aluminium) which has been set on the axle by pushing at bottom of finger, thereby rotating finger into the blade. I would feed it by rotating the finger on it's axle into blade with a big stick between me and the finger.
I suppose would need to have a nut on the end of the axle and set the blade so it makes a perfect semicircle. It doesn't sound great but i got a quote for $800 to make 20 fingers ha ha

[Ian Worley]

Stephen, if you're going to try making these yourself with limited/makeshift machining, a standard router ($50-$75 on Craigslist) mounted upside down on a table would be a better choice than a Dremel as described -- you'd likely break a few blades and put out an eye or two before you finally burned out the motor on your Dremel (and still end up with mediocre results). Get a proper end mill cutter ($15-$20 at Enco, Grizzly, etc.), preferably a two-flute with a 1/2" shank to minimize flex and chuck it up in the router. Routers can handle the lateral force like a mill (unlike a drill press) and most decent routers come with a 1/2" collet.

You would want to use aluminum, working in steel with this type of setup would be pretty sketchy. You would want to cut away as much excess material as possible on a band saw or something first; pre-drill the axle center holes in the finger blanks then take shallow passes (on all 20 fingers each pass for consistency) until you get them where you want. Jig up some sort of movable radius point that you can adjust progressively closer to the bit each pass until you hit the desired radius, perhaps something with an extended lever you can clamp the fingers to via a wingnut to give better control as you rotate them. Make a finished prototype first to track your steps.

This could still prove a very dangerous operation -- be very careful!

Do you have a drawing of what you plan to make? Are they one-piece pull-release style? I have a mill in my shop (just up the road in Sacramento) and assuming they are fairly straightforward I could probably make something for you fairly quickly out of 1/4" 6061 for a lot less than $800.

[Ian Rae]

My trick for shaping the fingers is to make them in pairs:-



Steel over here is metric, so I'll translate. The stock is 1"x 1/4" (you could use 3/4"x 1/4"). I drill a pilot axle hole and fit a 1" washer almost flush with the end of the rectangular blank. To save time I cut the exposed corners off and then shape it on a grinding wheel using the washer as a guide.



The next picture shows parts for my keyless tuner but the principle's the same. I rock the parts on two rods - the lower hand goes back and forth on the file while the top one turns the work simultaneously through 180° - should have done a video.



Then I put the work in the vice end upwards and finish off with emery cloth and sandpaper.



I was worried that this process might not be accurate enough and would give a poor sound, but no, it works!

[Sonny Jenkins]

These were made of 6061 for my homemade "Kline" (future),,not polished or spaced yet,,,shaft has masking tape to retain temporarily. I was going to make them from s/s or 7075, but Paul Redmond told me he made his last OnTrac from 6061,,,hey,,that's good enough for me. I will be happy to make these,,,or any other parts that are within my capabilities at a very reasonable cost. Let me know what you have in mind.

Also a pic of the logo I made for my Kline restoration.

[chris ivey]

what material is used on late 60s-early 70s push-pull changer fingers?
i would think that would be a good reference.

[Stephen Williams]

I do love the forum......fantastic response.

Thanks a bunch Ian for the advice. i do in fact have a decent router and if i go ahead i will use it. I have the urge to do everything myself but may relinquish the thought and send the design or prototype to one of you guys. It does seem fraught with dangers so i will be careful and stop if it feels too sketchy.

When i worked as a carpenter i refused to use a table saw because every carpenter who had lost fingers had done it on a table saw.

My first go-round I used a Collar shaft 5/8" dia. and used the set-screw hole to fix it to a solid aluminium piece 3/8" x 3/4". Worked pretty well.

[Chris Lucker]

There is a lot of nonsense stated above.
Aluminum, whether cast or 6061 T6 does sound good in steels. It worked with Bigsbys, sho bud permanents and countless other steels.
And the axles I know of are drill rod or hardened steel. Yes, they gall. But they can be replaced after a couple of decades of use.
The best sounding Emmons guitars had the cast fingers, in my opinion
And, I have seen more wear in fingers due to the guitar being in the case and weight on the strings pressing into the fingers than from play. Look at an old Emmons case, for example, with a padded lid yet players put the guitar in strings down. The bottom of the case is not padded.
Does anyone know the first guitar company that made cases for guitars to be stored strings down? Was it Fender, with its 1960s steels? Emmons had the cutouts in the undplates for a reason.
It never made much sense for pedal steels to be encased strings up, but so many companies did it that way for so long. Early sho buds wouldn't fit upside down. Bigsbys certainly could not. I have never had a really early Marlen. I forget how my 1964 Blanton fits in its case (number one).
But back to the original issue. Aluminum is musical in pedal steel applications. The 6061 T6 sounds great. Go harder and it gets shrill. Maybe the 20 series sounds good but the 70 series is harsh.
I do not like telecaster saddles out of aluminum, though. And don't like steel, either. I make mine from nickel silver.