4 to 8 string conversion?

WarriorJoe7 · #1 04-20-2008, 10:37 PM

OK so I read all the conversion threads and none address this issue directly.

I have a bass that is a perfect candidate for conversion. It is a Hartke XL-4 with a seemingly very strong and stable aluminum neck. It also had a wider than normal nut (1 11/16.) I also happen to have an extra body. I want the new tuners to be at the body end like the 2 examples here.

http://cgi.ebay.com/Vintage-Gibson-E...QQcmdZViewItem

http://cgi.ebay.com/Kramer-Aluminum-...QQcmdZViewItem

I just don't know what they are doing at the headstock end. Anyone know? I thought about drilling holes in the headstock at an angle (wouldn't even need ferrules since the headstock is aluminum.)

So as far as I know here is what would need to be done.

1) route the new body to accomodate 4 guitar tuners behind the bridge
2) Get an 8 string bridge
3) Get rail type pickups
4) Get 2 new brass nuts (one for octave below string fundamental, and the other for vice versa.)
5) Figure out how to anchor the ball ends at the headstock. What would I do if this were a wood headstock other than the same thing with ferrules installed? What are the other ways to do this? (I already know the standard 8 tuners on the headstock method but I am not going there.)

comments please!

WarriorJoe7 · #2 04-20-2008, 11:40 PM

I vow to have another Japanese tune 8 string but for now this will do...

Angus · #3 04-21-2008, 01:44 AM

Why would you use two nuts? That doesn't make sense.

I'd really, really highly recommend you not do this, especially given the way you want to do it. There are far better (ie, less invasive) ways to do this. Even so, it'll be really expensive even when you do all the work yourself because of the fact that you'll have to buy all the hardware and refinish the instrument (given that you're going to route into the body), etc etc.

I did it with a bass, but I didn't have to swap pickups or do any refinishing of the body and when I bought the bass it needed a new bridge and hardware anyway (and I already had the tuners). Mine cost me a total of $25 to do, which was just the cost of the bridge. I wouldn't have done it if I didn't already have all the pieces hanging around, and I DEFINITELY would NOT have done it if I had no parts, had to do all the extra work you'll need to with that plan, and was already planning on buying another 8 string anyway.

The aluminum neck will make it much harder for you, too- I'd advise you to stick with a regular wood necked bass if you decide to do this. Any neck can handle the tension, especially if you use light strings.

Basshole · #4 04-21-2008, 02:27 AM

Joe, you only need one newly slotted nut. Put the octave strings above the bass strings.

You can drill the holes in the head on an angle, just as you described.

You can put the tuners on the body by routing, and I think you can use this bridge:

http://www.warmoth.com/hardware/brid...n=schaller_471

It says the strings stop at the bridge, but you can pull the octaves straight through to the tuners, IIRC...I remember seeing this bridge used to do a similar conversion.

Probably no need to touch the pickups.

WarriorJoe7 · #5 04-21-2008, 06:53 AM

Fortunately I have most of the parts lying around. I have an extra body lying around that is not being used and I have pickups and a preamp lying around. I have 4 very good guitar tuners. Since it is an extra body, it is solid black, and the cut will be on the back edge I do not care at all about refinishing the whole body. Heck I might just seal the new cavity and call it a day. So really the only part I need to buy is the bridge.

But yes drilling into the aluminum headstock makes me nervous. I was going to try drilling into another piece of aluminum for practice but didin't think of a machinist. I was trying to see on here if there was another method instead of stringing the ferrules through the headstock (and if I did this yes I would have it at an angle so that there wouldn't be a 90 degree cut on the angle.)

So is there any way I can do this without drilling holes in the headstock. I thought I remember seeing something about a conversion kit and a nut that holds strings. Does that work?

So my biggest expense may be a machinist (surely under $100 though) and then otherwise the bridge ($50 off ebay.) Other than that I have 2 of these basses and I really like them but was going to sell one.

BigRedX · #6 04-21-2008, 01:00 PM

A couple of things to bear in mind.

I too like the idea of being able to string the octave strings either above or below the main strings, but you'll have to do some clever stuff with string angles behind the nut and bridge to achieve this. Looking at my Washburn 8 string it looks fairly easy at the head, where the octave strings break at a more acute angle and could pass under the main strings, but behind the bridge all the strings break at the same angle so it won't be quite so easy. Do you have a bridge in mind that you're intending to use?

Normally the main and octave tuners are different. Bass tuners for the main strings and guitar tuners for the octave strings. I've seen guitar tuners used on basses, but only on 30" scale and then you have to pick your string brands carefully or they don't fit. Also since you're using the Hartke neck it's already set up for bass sized tuners.

Which leads me to my second concern - the construction of the Hartke neck. These are notorious for pulling apart under tension since the aluminium core isn't actually attached to anything other than being sandwiched between the neck and the fingerboard. The strings pulling on the headstock causes the head to pull forward and the fingerboard to separate from the rest of the neck at the nut end. I certainly wouldn't want to add any more tension to the head in the shape of 4 more octave strings pulling on it.

WarriorJoe7 · #7 04-21-2008, 04:25 PM

Hmmm yeah maybe the hartke is not a good candidate... Can you point me to where someone had the seperating fingerboard problems.

I guess they should have used bolts instead of screws on the neck pockey (like modulus) and then have the aluminum part of the neck threaded to accept the bolts. But as it stands they better have extremely strong fretboard glue for these babies to last.

BigRedX · #8 04-22-2008, 01:35 PM

Here you go - not a pretty picture:

I bought one of the aluminium sections of these necks from on ebay. Having seen this photo I'll be looking at making sure that I can make some of the neck bolts attach through the reinforcing rod part as well as the wood of the neck before using it.

WarriorJoe7 · #9 04-28-2008, 02:40 PM

ooohhh that's ugly. So I guess I WILL NOT be using a standard hartke for this.

I also have one of the aluminum sections. Please document if you come up with a solution Bigredx. Maybe I will make an 8 string out of the new neck if we can find a way to anchor the aluminum. Thanks for the researcyh and the pic to deter me. I was dead set on doing it until that. Could have been a $650 mistake.