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Design and build of a Franklin style 12 string.

Posted: 2 Feb 2021 8:14 pm
by Don McKinley
I've always wanted to play pedal steel but too many other interests deffered my action till now. Here is my start. I borrowed a nice Franklin 12 string E9 and since I love the way Paul Franklin plays and I know he plays a Franklin I decided to copy the one that I borrowed for my own use. One question. I see all of the pedal steel guitars have a tremendously large dimension between level of the the strings and the support the table that stands off the tension. Does a large dimension here cause good response or would a smaller distance be better. Since most steels I have seen seem to have a very large string to table dimension, I would suppose that the consensus is that a large dimension is best. With string basses I know that a large break angle over the bridge kills the response. Of course the PSG is nothing like the string bass & so I wouldn't expect the same mechanical principle to apply.

I've made dozens of parts and soon will have many more. I'll try to get the instrument finished up in the next month or two. Here is my original counterfeit bootlegged design. I'm indexing the peghead and the bridge into the table in order to minimize
cabinet drop.

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Don McKinley

Posted: 2 Feb 2021 9:49 pm
by Jim Pitman
I believe the fact that the strings on most PSGs are quite high off from the body is born of practicality given the design of the usual all pull changer. To get good mechanical advantage at the forces required to pull a string under tension without excessive friction requires a minimum scissor length not be exceeded. The fact that a typical finger axle is 1/2" in diameter and needs rigid support dictates pillow blocks that have some beef. Laying a heavy bar on strings dicates some minimum of string height is required off the neck for practical reasons. These aspects contribute to the typical string height we see.
Aesthetics too have a bearing. One could make a real deep body so as to use the same changer design but locate it lower in the cabinet. However, it might look funny or at best, unusual. There's a practical advantage to doing that though. I maintain if you could locate the pivot point of the fingers smack dab in the thickness of the top wood, the pull tension would be equal on both sides negating that last smidgeon of cabinet drop.
....but...this radical change would likely have an affect on the resonance of the guitar which may have a good or bad affect on the sustain/tone. That's the one thing that is very hard to model/simulate.
Furthermore, would it be a Franklin design?
It's an admirable effort you are undertaking but consider whether you want to imitate or innovate. If you really love the Franklin tone it less risky to imitate.

Posted: 3 Feb 2021 7:48 am
by John Swain
FWIW, Winnie Winston's "beast" the strings were high off the body and he decided it was unplayable. Bud Carter designed the Carter guitars very low off the body because he determined it was advantageous. I'd do. Some research on both!

Posted: 3 Feb 2021 8:11 am
by Roger Crawford
Do some research on knee lever placement as well. Having the all against the rear apron may not be comfortable to use.

Posted: 3 Feb 2021 9:07 am
by Greg Cutshaw
Interesting project. Are you going to copy the details of the changer fingers to get the same leverage and raise lowering range capability?

A few Franklin changer parts pictures here:

https://bb.steelguitarforum.com/viewtop ... 1a2c3010d5

and here:

https://bb.steelguitarforum.com/viewtop ... c&start=25

Posted: 3 Feb 2021 1:43 pm
by Don McKinley
Thanks all for the feedback. It has taken me so long to do the design work that I guess I have pretty much frozen the design. I'll definitely check it out, but if I can't get comfortable with the knee lever placement I may rearrange things underneath later. I don't know yet how much is me and how much is the PSG.

Does anyone know if Franklin's necks are stressed onto the body or are they dead flat against the body. I have an idea that it may make a difference, but I don't know good or bad. I was wondering if a stiffer prestressing as opposed to just native strength would produce more or less responsiveness. Kind of like a bowed musical saw that has an "S" precurve.

Greg: yes I have copied virtually everything. I'm not sure that the setup is 100% original but as it is, it seems to work well. I think I will put it together just the way the original was put together.

Posted: 4 Feb 2021 10:03 am
by J D Sauser
John Swain wrote:FWIW, Winnie Winston's "beast" the strings were high off the body and he decided it was unplayable. Bud Carter designed the Carter guitars very low off the body because he determined it was advantageous. I'd do. Some research on both!
the closer the strings are to the body, the less cabinet drop affects the strings (ask Fender Players... Ha!). It's simple geometry. And Bud Carter understood that.

... J-D.

Posted: 4 Feb 2021 2:11 pm
by Thomas Stone
Don -- Don't mean to get the thread off track, but may I ask what 3D CAD system you're using? I'm using an ancient program that is no longer sold or supported, so I'm looking to upgrade/modernize and am curious what people are using.

Posted: 5 Feb 2021 11:41 am
by Paul Strojan
I am impressed by the CAD work. It would be a great service to the pedal steel guitar community to have access to the CAD files to get parts made for their guitars. Best of luck.

Posted: 5 Feb 2021 12:58 pm
by Jack Stoner
A very complicated reverse engineering project. Good luck.

It can be made to look like a Franklin but the Franklin's unique sound probably will not be there. But who knows, the sound may be great.

The necks are cast aluminum. Not a solid piece of aluminum. Mr. Franklin showed me a CNC produced neck and he liked it as it had a "bell sound" if tapped. This was at the end of production and if it was used on a steel probably the last or next to last that he built.

The roller nuts are not gauged, intentionally. This is a carry over from later Sho-Bud builds as it "fixed" a problem that they once had, according to Mr. Franklin.

I agree with the knee lever locations are not right and potentially could interfere with pedaling. Along with not interfering with pedaling, they have to be placed so they can be used in conjunction with certain pedal combinations. And finally placed so the levers can be folded down for transportation.

BTW, I was a 38 year Franklin owner. I would still own it but at age 83 I've mostly retired from active band playing (retired as a musician can be).

Posted: 5 Feb 2021 6:39 pm
by Kelcey ONeil
The string height is most often a byproduct of changer design or aesthetics, and not an intentional dimension; whether this is a good thing or not is another story. Some newer Jackson designs have taken cues from old Fenders and have a recessed key head and a much lower neck, presumably with string height in mind. The lower the string height, the less leverage the strings tension have to pull on and “bow” the body. This of course helps alleviate cabinet drop, and also helps to keep everything flat and well joined to the body.

In regard to the Franklin neck, they were indeed cast aluminum, and as such would be machined an a flat plane. Cast material has more of a tendency to break rather than bend, and the shape of the neck is such that it indeed provides a structural element all its own towards keeping the body flat. “Tension” is largely provided by how the aprons fit in the end plate, most agree that having to slightly squeeze the aprons together to fit in the end plates is ideal to provide “upward” tension on the top of the body.

Also, all the other large aluminum parts( key head, neck, end plates) on a Franklin were cast aluminum as well. Cast parts largely went out of style due to poor foundry quality and rising prices for smaller batches, rather than for structural, tone, or production issues. Cast aluminum( depending on alloy of course), often tends to “ring” better than billet material simply because of its lighter and more porous nature. Billet material is extruded, and as such has a linear grain to its structure that can limit resonance, or perhaps more importantly, limit the frequency or direction of vibration transfer to the body. This is of course somewhat subjective, but there seems to be something to it more than just “the old way was better” lol.

Design and build of a Franklin style 12 string

Posted: 5 Feb 2021 8:23 pm
by Bobby D. Jones
About 1970 I took on building a steel using a Sho-Bud D10 to clone. I learned a lot in making certain parts. When I got 3 pedals I wanted to play it.
Good Luck in this project.

Posted: 7 Feb 2021 11:59 am
by Bo Borland
My 2008 Derby D10 has always had black ooze to the top of the changer rollers. It did it when it was brand new and still does .

Posted: 7 Feb 2021 10:32 pm
by Jim Palenscar
"Black ooze" is basically aluminum residue mixed with lubrication and basically harmless- wipe it off from time to time. I'm not convinced about the additional structural nature of the neck although as in the recesses of my mind I once measured cabinet drop w and w/o the neck on the same guitar and wasn't impressed that there was a difference-your mileage may vary.

Posted: 8 Feb 2021 2:48 pm
by Bobby D. Jones
That black ooze is a combination of aluminum and human sweat. If aluminum is not polished and some coating or anodized it will make black ooze.
I had a friend who wanted a light bar to play his steel. I made it out of aluminum and had it chromed. He went on tour with it to New England states, With Freddy Hart. He said every time he played with it his left hand was black at the end of a show. Looked good on paper but was a mess in reality.

Posted: 15 Feb 2021 4:01 pm
by Don McKinley
I would like to make cast end plates and peghead but the foundry cost will probably force me to machine them. I think the brittleness of the cast material probably adds to the resonance of the PSG. The more ductile metal probably causes a bit of damping. I think that I will make the neck out of wood and if everything turns out good, I'll toss the wood one later and machine a metal one. I have a metal one already sized up ready for machining. I am going to make the string spacing just a tad wider than the .350 on the original to make it .375. with 12 strings the extra .025" adds over a quarter of an inch to the width of the instrument. I had a custom width made for the pickup. Today I have about 1/2 hour left to go on the bell cranks. Hoping to start on the changer today. There are so many great ideas on this site. I Like the two piece bell cranks that were pictured in an earlier post. Definitely more machining but much more serviceable for modifications.

Thomas Stone:
The cad program I'm using is great. Its Rhino3D. You can download a fully functional copy that is limited to 25 saves, (I think they're still doing that.). After 25 saves the program still works for practicing and getting familiar with the program but saves are not allowed anymore. For the machining I'm using an old version of VisualMill. (VisualMill v4). The VisualMill has improved vastly since version 4, but I think that there are much better CAM programs out there. Problem is cost. So few copies of the CAM software are sold that they have to make it expensive, and then the upgrades that you would like to see aren't economical for the producers to add. The documentation on the VM was terrible but the price beat the competition all to heck. I purchased many years ago.

Posted: 15 Feb 2021 4:28 pm
by Ross Shafer
Really great stuff Don. I have a pretty good idea of the time and commitment you have in this, kudos! Can't wait to see the progress and results.

Posted: 15 Feb 2021 4:55 pm
by Don McKinley
Bell Cranks done, on to the changer levers and fingers.
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Posted: 21 Feb 2021 7:55 am
by Daniel Stinnett
How are you coming along with your project Don? As a Franklin owner, I would love to find a source for my guitar. Those cranks look good from what I can see. Please keep us posted on your project.

Posted: 26 Feb 2021 9:35 am
by Don McKinley
Hi Dan,
Here are some more pics of the progress. I'm including some 'how to' pictures for those interested in the details of the machining...

I couldn't get the right size aluminum in a timely way so I had to resize.

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Cut out the Lower Levers
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Decided to drill the rod holes after I had already cut out the levers and so needed secondary operations. Should have done it at the same time.

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This is how I bent the levers. All the same. The metal is like real stiff putty. It's amazing how doughlike it is. It just lays right down with very light tapping despite how stiff it is. It is just mild steel. I hope it is the right stuff. I think it will be fine. The hammer looks big in the picture, but it is just a little tiny jewelers hammer.

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I got stainless rivits. I didn't want to shell out for an expensive rivet setter and so I used the dremel and ground a dowel pin into a makeshift setter. Worked like a charm but I had to take real heavy blows to form them. Almost as hard as an experienced framer would use to drive nails.

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And the rivit...

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And now some rings to supply the right string spacing which in my case, I wanted .375". Thats more than most steels if I'm not mistaken, but the one I tried seemed real close together. It adds up over 12 strings. This will be kindof a wide sucker...

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I had to sharpen the end mill several times so far. I can't believe how well the cutter holds up though. This is by far the most milling of steel that I have done. I have used the machine mostly for wood previously. This is my precision end mill sharpening setup. A steady hand and magnifiers helps a lot...
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Sorry for the length of the post, but I thought some less experienced readers may be interested in some technical shots and description. I'm always interested when others post it.


And now first assembly of the changer with the spacers included. I got the wrong length of shaft and wrong material and so have to reorder the shaft. And.. yep that's me in the picture.
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Posted: 26 Feb 2021 12:43 pm
by Dennis Montgomery
Don McKinley wrote:
Sorry for the length of the post, but I thought some less experienced readers may be interested in some technical shots and description. I'm always interested when others post it.
No apology needed Don, I love all these pics and details...keep 'em coming! Honestly when this thread appeared my first thought was, "goodness, why doesn't he just find a Franklin or another 12 string somewhere and save all the time and effort?" Now it looks like it's starting to really come together and I, for one, am fascinated to see your accomplishments every step of the way ;-)

Posted: 27 Feb 2021 7:27 am
by Bo Borland
Awesome photos ! Thanks for posting

Posted: 27 Feb 2021 11:55 am
by Don McKinley
Roger Stoner and Jack Crawford. Thanks for the comments on the knee levers. I was noticing when I tried out the one I am copying that the left knee combination seemed to be too offset toward the right hand so that I had to adopt a slightly difficult reach with my left foot to get at the levers. Did either of you (or anyone else) think that that is an issue. I spent so little time playing that I couldn't tell if that was just a personal pecularity or if it really is too far to the right. I see that you Roger mentioned not liking the levers too close to the rear apron. It would be straightforward to move them around at this point. Thanks for the comments everyone. I hope to start machining the end plates today.

Posted: 27 Feb 2021 3:34 pm
by Jack Stoner
The floor pedals are a little more centered on a Franklin and do not start (Pedal 1) far to the left on the pedal board. The knee levers, particularly the LKL is set to not interfere with Pedal 1 (A pedal) but set perfectly to work in conjunction with Pedal 1. Or "the pedals and knee levers are in the right place".

Here is a picture of the underside on the D-10 I had (S/N 65).

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Posted: 28 Feb 2021 12:03 pm
by John McClung
Fascinating thread, Don, and I love those CAD drawings with transparency! You ought to have a chat with Ross Shafer, designer of the new Sierra. He went clear back to Square One and rethought just about everything about pedal steel design and reinvented much of it for Sierra steels. He works in CAD, you're like two peas in a pod!