Four string fretless acoustic/electric (chambered)

[Will_White]

The glue up appears to have gone well. I block sanded it down to at least get a look at it, I'll hit it with the orbital sander later on and get rid of the rest of the glue/sawdust. It looks great and feels plenty strong enough. With the X-bracing underneath this will be fine as a top. I know the picture makes it look messy because of the glue and the stuck in sawdust, but it will be a clean line when I'm done. I'm pretty happy with it!

Now I can get on with the rest of the body work. I have two mahogany slabs, I picked out the best one for this shape and will start on that as soon as I get the chance. I think I can screw the top onto the mahogany while I work on shaping it by putting screws in where the strings will go through and into the neck pocket area.

I always use the grain of the wood as a guide for shaping the body. I start with a general idea of what the body will look like, but the end result is never what I start with. I know right away that the lower horn needs to be further out or thinner and the upper horn needs to be longer than this to prevent neck dive. I know this body will be super light, so it's really important that strap button is at the 12th fret, if possible. I have very little extra material to work with in this case, but I think it will work out.

My next concern is the placement of the transducers for the pickup, the instructions are pretty prescriptive about where exactly you place them - one between the 1st and 2nd string and one between the 3rd and 4th string right under the bridge, so before I glue the top onto the body, I have to have the bridge location figured out. I'm planning on having the strings go through the body using ferrules in the back, then building a bridge out of wood. I plan on setting the intonation by carving individual string saddles. Perhaps a bit ambitious. We shall see.

On the bridge, a floating bridge would be easier and adjustable, just move the ferrules back a little, or use a tail piece, you'll get more acoustic volume that way.

 

[Jisch]

That's a great idea - floating bridge. I just did a search and found T2W's example wow that looks awesome and easy money. That's what I'm going to do. Thanks for the idea. I was planning on having the ferrules pretty close to the back anyway.

 

[Jisch]

I haven't had any time this week to really work on things, but I surely will this weekend. While I'm a fair distance from time to round over the edges, I want to make a decision/plan. My original plan was to make this as round as possible, using a 1/2" roundover bit, but I'm now thinking of using a very slight round over on the front and a more aggressive one on the back. I like the comfort of a round body, but I think the front would look better with a more definitive edge. Thoughts?

 

[Will_White]

I haven't had any time this week to really work on things, but I surely will this weekend. While I'm a fair distance from time to round over the edges, I want to make a decision/plan. My original plan was to make this as round as possible, using a 1/2" roundover bit, but I'm now thinking of using a very slight round over on the front and a more aggressive one on the back. I like the comfort of a round body, but I think the front would look better with a more definitive edge. Thoughts?

IME as long as there is a roundover the size of the round over doesn't matter that much for feel, I think a 1/4" roundover would keep the front edge more defined and then either a 1/4" on the back for symmetry or something larger for more comfort.

 

[Jisch]

I got some work done today.

I trimmed the front. I need to sit down with a pencil and get the final shape. I probably should have just waited to cut it until I had the final shape, but hey, not everything is logical. I ran it through the sanding planer to get rid of the extra glue/sawdust. This is the back (i.e. this will be inside the bass:

I cut out the mahogany for the back - I matched it to the front that isn't done yet (this will be the back of the bass).

The two together - and this is the front:

I trimmed and carved out the bottom of the fingerboard, I wanted to add a little interest:

And finally I glued up the fingerboard and the wings on the headstock. I don't know what the headstock shape is yet - this is actually the first four I've built so symmetry is possible, I'll have to think about it:

Tomorrow I'll get the sides of the neck established and maybe start carving the back. I'll need the final shape before I start removing material from the body.

 

[Jisch]

Glue up went great - no gaps anywhere.

I took it out of the clamps and cleaned up the sides.

Now that I have the final dimensions of the neck, I'll finalize the shape. I have a lot of work to do on the headstock, but I left it big so I don't end up in trouble later.

I probably won't get anymore done for a week or so, but I'll be thinking about it for sure.

 

[Jisch]

I couldn't help myself from stacking up the parts to see what it will look like. Obviously the huge block of wood will be carved down considerably to become the floating bridge. My thought is to route out a channel in the middle of the walnut and put a 1/4" thick piece of ebony on end in the slot to act as string saddles. I'll carve the ebony so that the individual string saddles are in the right spot for intonation. I am not sure if 1/4" will be enough to really set intonation - it would be on some of my basses, but not on others. Since it's floating I can also angle it slightly as needed. The ebony, especially standing on end, should do a good job of transferring the vibration of the strings to the top of the bass. I'm thinking that I can easily change that ebony to a different wood if I don't glue it into the slot, I can put a set screw to hold it in place, the string tension will hold it in anyway.

The thing is I need to know where the bridge is going to sit so that I can glue the transducers from the K&K pickup in the correct spot BEFORE I glue the top onto the body. I am thinking I can string it up before gluing using clamps to hold the top in place. It's a 34" scale and the transducers are about 1/2" in diameter, so I am sure I can get them close enough.

Getting psyched about this project, but bummed it's going to sit for a week. I love the process of building and as I get deep into it I sometimes forget that at the end I'm going to have a new bass. That kind of just hit me tonight.

 

[Will_White]

I couldn't help myself from stacking up the parts to see what it will look like. Obviously the huge block of wood will be carved down considerably to become the floating bridge. My thought is to route out a channel in the middle of the walnut and put a 1/4" thick piece of ebony on end in the slot to act as string saddles. I'll carve the ebony so that the individual string saddles are in the right spot for intonation. I am not sure if 1/4" will be enough to really set intonation - it would be on some of my basses, but not on others. Since it's floating I can also angle it slightly as needed. The ebony, especially standing on end, should do a good job of transferring the vibration of the strings to the top of the bass. I'm thinking that I can easily change that ebony to a different wood if I don't glue it into the slot, I can put a set screw to hold it in place, the string tension will hold it in anyway.

The thing is I need to know where the bridge is going to sit so that I can glue the transducers from the K&K pickup in the correct spot BEFORE I glue the top onto the body. I am thinking I can string it up before gluing using clamps to hold the top in place. It's a 34" scale and the transducers are about 1/2" in diameter, so I am sure I can get them close enough.

Getting psyched about this project, but bummed it's going to sit for a week. I love the process of building and as I get deep into it I sometimes forget that at the end I'm going to have a new bass. That kind of just hit me tonight.

For positioning the transducers, route your neck pocket in the top then measure from the nut to 34 1/8" or from twelfth fret to 17 1/8", if you are going to use them under the top but most under bridge transducers are meant to go between the top and the bridge, I'm not sure with the K&K's though.

I would move the neck up the body a bit if that's where the bridge is going to be, you want the bridge as centered in the lower bout add you can get it for most acoustic volume.

 

[Jisch]

Ok, I'll see if there's room to move the neck up, that's a good idea. I thought about it a little before as I was looking at bracing - with the hole where it is, there is not much room for bracing. I may just forgo any bracing at all. I think with the strings going through the body, the tension on the top wood will be a lot less than if I had them tied off on the bridge like with an acoustic guitar. Also this maple is a lot stronger than spruce usually used on an acoustic instrument. I'll do some tests and make the final decision once I get the body hollowed out.

The K&K transducer goes inside the body, not between the bridge and top - in their literature they tout this as the way to get fuller sound out of it. Of course that also means that installing it on a fully built instrument is a major pain involving this little plastic template and a golf tee - I am glad I don't have to do that!

Thanks a bunch for your input @Will_White!

 

[Jisch]

It looks like I _can_ move the neck 1 1/4" max, but I don't think I need to move it that much, moving it a bit over 1/2" looks about right, if I move it more than that it starts to look funny.

 

[Jisch]

I got to spend a few hours in the shop today.
I started here - I put two screws in to hold the front in place while I figured things out:

I finalized the body shape, first I shaped the front, then transferred that to the back and cut/sanded it to shape:

I used various forstner bits to take out body material. I didn't notice how cool this looked when I was doing it:

Lots of shavings:

Slap the front on and see that centering point is leaving annoying marks you can see:

A few minutes with some aggressive paper on an orbital sander, the hand held rotary tool and a chisel took care of that (I also got to the "blood" part, when my finger slipped under the chisel at an inopportune moment - all I have left is the tears part - hopefully tears of joy when I hear how great it sounds). That island in the back is for the string ferrules:

Looking pretty good now - and it makes a really good hollow sound, I think I'll be fine with the top vibrating enough for the transducers:

I'll hopefully get the neck pocket routed tomorrow. I need to get inserts!

 

[Jisch]

More time in the shop today.

I probably should have taken more pictures of the process (it wasn't as elegant as I had hoped), but I got the neck pocket done. I know I probably should have waited to do this until everything was glued up, but I really want to do a dry fit with everything on it before gluing, just to check things out. I'm uncomfortable with enough that needs to be done that it will make me feel better.
Anyway after several gyrations I got the pocket done:

and my new favorite tool the Surform. I used a belt and orbital sander to do past necks. Wow this was so much easier and comfortable. Love it. Of course this being mahogany and the other necks being rock maple makes a difference as well.

I'll need to do more on it, but good start. I didn't touch either end.

I'll take some more pictures, but the neck joint is about as good as I could have hoped:

I need to figure out how to form the back, it looks weird right now, but I'm not used to doing bolt ons.

 

[reverendrally]

I built something similar to this recently...

Build 10 - Liquidambar 32" | Page 9 | TalkBass.com

 

[Jisch]

Interesting instrument! My biggest concern (still) is the K&K pickup and whether it's going to produce enough sound, I see you are using a pickup on yours.

Like your instrument, there are so many things different about this one from anything I have done before I just don't know what the combination of all these "one offs" is going to be. I'm hoping for a boomy, natural sound, only time will tell - I figure I'm 2-3 weeks away from making noise - though I expect to be able to do a pre-finish test before then.

 

[Jisch]

I have a question for the group - I have three worm holes in the bottom of the front. Do I stabilize them with CA (they are pretty clean right now - not rotten around them or anything) or do I fill them in with a sawdust/glue mixture?

 

[Hopkins]

The way you pieced that top together is pretty slick. I was wondering how you were going to get a useable top out of that board. Nice job.

 

[Jisch]

thanks! I was going for something completely different, the suggestion to do it this way made sense. Unfortunately there are few skills that transfer from bass building to door hanging. Ready to pull my hair out. Hopefully I'll get back at it this afternoon.

 

[Jisch]

A little more time in the shop after a morning of frustration installing an outside door at my house (I got it done, but there was quite a bit of swearing involved).

I installed the inserts today - so the bolt on became a bolt on today:

My process: I double stuck the neck to the pocket, just to ensure it wouldn't move while it was on the drill press table - the tape wasn't enough to really hold the neck, but it was enough to prevent any slipping between drilling individual holes. I thought I had the press set to go into the neck 1/4" or so, turns out it just barely hit the neck (whew). I used a forstner bit to set up the recess, then drilled through the body to the neck using a drill that was the appropriate size for the bolts (maybe a bit big), then drilled out for the inserts. The insert package said to use a 1/4" bit, but after trying that on a test piece it was obvious this was going to be too dangerous (I had some major splitting). I sized up one and coated them with beeswax - I feel comfortable that they are set and will not come loose, and most importantly they didn't damage the wood.

The inserts:

I am not entirely happy with how this looks from the back - it looks like the bolts are too close to the edge, but I can't really figure out how it could be any different, I'm not upset, but I'd have to stare at this more to figure out what I could do differently next time. The bolts lined up perfectly - no binding and I found all four by just turning the bolt from the front:

Then I started working on carving the end of the neck and the back of the bass:

I was hoping to have this done by the end of this week (a vacation week for me), but I can see now that it will be another few before I'm done, while the major stuff is done, I know the remaining small things will take a lot of time - bridge, thumb rest, transducers, tuners, headstock etc, etc. Lots to do!

 

[Jisch]

I only had a little time in the shop today

Side dots:

Ferrules inset for the string through, they line up perfectly, which is due to some planning. I drilled the outside two from the top, then established a straight line between them, then I lined up the inner two from the bottom, that way if the drill wandered on the way down from the top it wouldn't mess up the spacing in back. I had one inner hole get messed up, but a few minutes with a rat tail file and I got it worked out (you won't see that from the outside). The bridge will define the final string spacing and the top will hide the ferrules from view, so if they are off underneath (I don't think they are), it's no big deal:

The inside where the ferrules will come through - next will be the holes through the top - scary stuff - they need to line up with the fretboard.

My island was a little off - I made it big just in case (good thing):

Headstock overlay:

Next I need to radius the fretboard, drill the holes for the strings to come through the front and finalize the shape so I can do the round off. I was preparing the router to round off the back and realized that the front and back aren't quite lined up yet. I think I'll do that after I get it glued up.

 

[Jisch]

Radiused the fretboard, it came out great, more sweat, lots of sweat. Flat end to end.