My Harley Benton 335 conversion to 12-string

JohnS37

I have ordered the parts and uploaded some images to a hosting site, so I don't have any excuse not to share this rather un-ambitious modding job with you.  I have a lot of experience of DIY stuff in general, and the adjective I would apply to most of my work is 'sloppy', but, hey, at least I'll give it a go.
OK, so this is the unsuspecting 335-alike, the donor vehicle.


Most of the conversion work will be in the headstock area, so this is what I'm starting with

I worked out that there was a good chance of fitting all the extra tuners onto the existing headstock, without enlarging it, if I re-positioned the 'main string' tuners, and I worked it all out in Photoshop.  The secondary tuners are banjo-style planetary tuners, like this:

and from the back:

The tuners I Photoshopped in are Firebird-style ones, but they proved to be pretty costly, so I have ordered banjo ones from China.  These should actually be smaller, so I'm keeping my fingers crossed.
While I'm waiting I have been thinking about the final finish of the front of the headstock, and I will probably veneer over all the new drilling work.  It will need a new logo, and I really don't like the existing Harley Benton logostyle, which is in the dreaded Brush Script, so I designed my own in MOP, (owing something to the Bugatti logo . . )

If I can manage all that intricate marquetry it should look something like this:

and this:

So, that's the story so far.  If and when my bits turn up I'll post some more.
Please feel free to comment, tell me how it won't work etc.  I haven't done anything irreversible yet!

WezV

I wouldn't cross the string paths

JohnS37

Yes WezV, you have a point, though in 3D they may be ok, depending on the relative heights of the holes in the tuner posts.  Suck it and see . . .

ICBM

Neat layout, but as WezV said I would definitely not cross the strings, even if they don't rub on each other - it will make the order confusing. If you're familiar with Rickenbacker 12-strings you'll know this if you ever come across one that's strung wrong! You may find it better to string the two middle ones on the opposite directions on the posts too, or the keys will turn in the other direction compared to the others on the same side. There should be enough clearance to allow the low D string to pass the octave G post.

JohnS37

I have to admit that I have form in the 'crammed headstock' department.  Five or six years ago I decided I wanted a five-string bass, but skint and cheapskate as usual.  So I found a cheap loaded body (Stagg! Made of MDF - even now I cringe at the thought, though it looked okay) and married it to a buckshee Strat-copy neck.  Yep - Strat.  With some filing and persuasion I managed to cram five full-size Fender-style bass tuners onto it as you'll see.  It meant winding the bottom string the wrong way round the tuner post, and making a perspex nut that had round holes instead of slots, but it worked.


Scale length was unusually short of course, and it was a pig to play, but hey, sometimes it's the journey rather than the destination, Y/N?
Around the first lockdown I decided it wasn't getting used much so I sold it, totally honestly with many caveats, on the bay.  And here we are, again.

ICBM

You didn't study under M.D. Phillips by any chance?



Although you seem to have refined his methods quite nicely .

Did it intonate correctly? It doesn't look like it would in the pic, but it could be an optical illusion.

JohnS37

Yeah ICBM, you can see all those notes clearly, they’re perfectly in tune.
I think the most expensive part of this, er, ‘guitar’ was the set of strings.
(The keen of eye amongst you may have noticed how the bottom string curves in below the nut - just one of the easy-playing fringe benefits of my design, dontcha know?)

JohnS37

ICBM said:

You didn't study under M.D. Phillips by any chance?



Although you seem to have refined his methods quite nicely .

Did it intonate correctly? It doesn't look like it would in the pic, but it could be an optical illusion.

Who is this M D Phillips of whom you Earth people speak?

JohnS37

Ah, him.  I taught him all he knows.

ICBM

JohnS37 said:

Yeah ICBM, you can see all those notes clearly, they’re perfectly in tune.
I think the most expensive part of this, er, ‘guitar’ was the set of strings.
(The keen of eye amongst you may have noticed how the bottom string curves in below the nut - just one of the easy-playing fringe benefits of my design, dontcha know?)

It looks like the bridge is much further from the 12th fret than the 12th from the nut, so I would expect it to play very flat - but I wondered whether, with the scale length so short and the strings so slack, they would pull so sharp when fretting that it was actually right!

At the nut they look like those rubber strings you get on ukelele basses .

earwighoney

JohnS37 said:

Who is this M D Phillips of whom you Earth people speak?

He is the Keyser Soze of guitar.

JohnS37

No, the distances are pretty much equal, and the intonation wasn't too bad considering. 
Just conventional Ernie Ball strings, but yes, I do remember those old Ashborys.  They played surprisingly well, nearly bought one once, from Johnny Roadhouse on Oxford Road in Manchester, back in the day.

JohnS37

earwighoney said:

JohnS37 said:

Who is this M D Phillips of whom you Earth people speak?

He is the Keyser Soze of guitar.

I had forgotten about him.  I had better watch Usual Suspects again some night!

JohnS37

Now that the 'festivities', such as they were, are out of the way I got back to my 12 string conversion.  Next job was preparing an old bridge for the new regime.  I took out the saddles and ground them down until the original string groove was (almost) invisible.
 
Next I stripped the strings off, removed the tuners, and looked at my photoshop version of the converted headstock, to see if any of the holes were in the right place to be kept.  Turned out that four of them were almost perfactly placed, so only needed to plug two of them.
I prepared some short pieces of ramin dowel to plug the middle two holes and glued them in - they were a tight interference fit after paring down the oversize dowel.
During the drying period I marked up the positions of the new holes.
 
When the glue had had a few hours to go off I started drilling the new holes -
 
 
headstock now looks like a piece of Swiss cheese!


Next jobs are to remove the old nut and make a zero-fret and slotted 'nut' to replace the old nut.  I have decided to go the zero fret route as I feel I can make it more accurately than a traditional nut-only job.

And this is where I need your help - looking at the guitar from the front, upright, do I put the main strings to the left and the secondaries to the right, or vice versa?
I know that some Rics have the mains on the right and the secondaries on the left, but most traditional acoustics have the main strings on the left and the secondaries on the right.
What do you think?  Pros and cons?

ICBM

I would go with the traditional acoustic stringing, as all other electric 12s I've ever come across other than Rickenbackers have too. Rickenbackers have a very unique sound which suits the reverse stringing, but others don't so much. Many years ago I built a solid electric 12 (double-cut Les Paul shape) and initially strung it Rick-style - it sounded so wrong I made a new nut for it to put it the normal way round, which was much better.

JohnS37

ICBM said:

I would go with the traditional acoustic stringing, as all other electric 12s I've ever come across other than Rickenbackers have too. Rickenbackers have a very unique sound which suits the reverse stringing, but others don't so much. Many years ago I built a solid electric 12 (double-cut Les Paul shape) and initially strung it Rick-style - it sounded so wrong I made a new nut for it to put it the normal way round, which was much better.

Okay ICBM, many thanks.  Sounds like the right plan.
I can’t get any further now without deciding that, as I need to groove the bridge saddles and cut the nut thingy that will go behind my zero fret.  I’ll go conventional.
Incidentally, I decided to make the zero fret out of a piece of mild steel, since I don’t have any fret wire, and in any case it needs to sit in the slot that originally held the old nut.
I have cut and polished it, and I’ll put the pics up when I have chosen the material for the spacer.

JohnS37

I decided that the plain 'piano black' on the headstock would be a little unadventurous, so I devised this:

It's a photoshopped image of a piece of Zebrano, bookmatched in p'shop, laser printed on plain A4 and spray-mounted onto a piece of cereal box.  Saves a whole lot of faffing to do the logo, and should look okay from a distance . . ?!
That's the 'zero fret' sitting there too.

JohnS37

Hmm.  Maybe I shouldn’t have revealed the secret of my zebrano veneer . . . 

JohnS37

Here's the headstock with my 'veneer' mounted, with a first coat of spray lacquer and markings for the tuner holes

JohnS37

And here we are, in swiss cheese mode again

JohnS37

Next job is to cut the string slots in the 'spacer'.  Can't really call it a nut, because I'm using a zero fret, but this bit locates the strings laterally.  Like a nut, it calls for very accurate cutting, width-wise, so I devised a paper guide on computer, working at a large magnification, then printed it out on paper and sellotaped it to the perspex blank.
In the photo I have cut a few slots, and the bottom D particularly looks wrong in the photo, but is actually OK in the flesh, don't know why.