Short scale semi-hollow body build

[Jisch]

Before I get to cutting, I printed two copies of this F hole shape then carefully measured where the top and bottom would be including the angle they are at. I traced them onto the body, then replicated what I traced using a french curve. The tracing was kind of rough and going over it with a french curve made it much better/smoother.

My original plan was to drill the bulbs then cut the swoopy bits, but the bulbs are not round, so I just drilled in the middle of the swoopy bits with a forstner, then cut the whole thing out with the scroll saw. I cut inside the line then used a rat tail and other files to bring it out to the line. After I was done with that I eyeballed side to side, where I saw discrepancies, I checked with a caliper and adjusted the smaller side to be the same as the larger side. I still have a bit more of that to do, but it's pretty close. The lower bulb goes over the edge of the carve so I had to kind of adjust the angle of the cut through the top so it's at 90 degrees to the top where it goes through.

 

[Jisch]

I figured I'd see how big I could make the control cavity side, then I could figure out if a preamp would fit. I also routed under the pickup, it doesn't have to be perfect, in fact it makes things easier if it's cut big.

There's plenty of room for a preamp, so I guess I'm going that way. There's enough room that I can put the pots on top of the battery, so I'll cram everything in that corner. If I could get a preamp with three pots, I'd be happy.

Heading over my dad's now to cut the control cavity cover. It'll be a small cover, but it would be that way regardless of preamp or not.

 

[5tring]

I figured I'd see how big I could make the control cavity side, then I could figure out if a preamp would fit. I also routed under the pickup, it doesn't have to be perfect, in fact it makes things easier if it's cut big. View attachment 3250761
There's plenty of room for a preamp, so I guess I'm going that way. There's enough room that I can put the pots on top of the battery, so I'll cram everything in that corner. If I could get a preamp with three pots, I'd be happy. View attachment 3250762
Heading over my dad's now to cut the control cavity cover. It'll be a small cover, but it would be that way regardless of preamp or not.

I know you said you don't like stacked pots, but for what it's worth in my bass I have an OBP3 with stacked v/v, stacked bass/treb, and then the mid with push/pull but I wired it so the push pull switches passive/active instead of mid select. Sounds BA and gave me the three-control look I wanted, plus easy switch to passive without a visible switch.

I agree with you about stacked controls looking a bit naff but that was the compromise I went for.

 

[Jisch]

I got the control cover cavity cut out. It's a weird shape, but it should work well. Probably the best one I've cut, I've been using my scroll saw a lot practice makes perfect and all that, I guess. That and my dad's scroll saw is dramatically better than mine (mine is a $40 rescue job).

I need to figure out how to hold the preamp and battery in place after I glue everything together. It would probably be good to figure that out before I get things glued up, otherwise I'll be looking at a ship in a bottle situation, which is all too familiar in my builds. Outside of figuring that out, I'm ready to glue this together, it always feels good to get to this point.

I've got to figure out how to secure the cover as well, but that's easy, and I can figure out later (i have some ideas).

 

[Jisch]

I know you said you don't like stacked pots, but for what it's worth in my bass I have an OBP3 with stacked v/v, stacked bass/treb, and then the mid with push/pull but I wired it so the push pull switches passive/active instead of mid select. Sounds BA and gave me the three-control look I wanted, plus easy switch to passive without a visible switch.

I agree with you about stacked controls looking a bit naff but that was the compromise I went for.

Interesting, how tall are the pots? I use audere preamps mostly and their stacked pots are super tall, EMG stacked pots are much shorter, but I'm not sure I can use one of their preamps with these pickups. I'm confused about their write ups.

 

[ctmullins]

EMG stacked pots are much shorter, but I'm not sure I can use one of their preamps with these pickups. I'm confused about their write ups.

You can. EMG has kits for active pickups and kits for passive pickups. Or, if you know the specs, you can wire up whatever pots you really want. Sometimes I route the pickups straight into the preamp, with a 25k volume pot afterwards. Other times I wire the pickups to a 500k volume pot, then to the preamp. Lots of choices.

The "HZ" kits are the ones designed for passive pickups. The only difference here is that you'll need to solder the Lace pickup wires to either an EMG cable with header, or directly to the EMG blend pot.

Invalid Link Removed

 

[Jisch]

Ok, thanks, I saw some disclaimer in there that said it was EMG pickups only (or that's the way I interpreted the language). I'll have to take another look at them.

edit: the height of the stuff inside the body might be a problem, I'll have to see if there's room. With the Audere I can stack the battery, preamp and pot all in the same column, then I'm back to the four pots.

 

[Jisch]

My suggestions:

• Try the passive blend knob first. The Alumitones don't behave exactly like normal magnetic pickups, and while I'm not an expert, they may pleasantly surprise you.
• If the passive blend doesn't work out, try a 3-way switch maybe?
• Skip the single-double switch. Those pickups are already pretty narrow-aperture.
• A crazy thought: two knobs, master volume and master tone. Each is a push/pull switching on/off one of the pickups.

Sorry, I didn't see this post before, maybe I should try a passive blend knob, and thanks for the note on the single/double switch - it would take up a lot of real estate.

 

[5tring]

Had another thought: what about going back to a passive bass with good old V/V/T knobs, but the two volume knobs are push pull switches for individual pickup single/double coil switching

 

[Jisch]

Had another thought: what about going back to a passive bass with good old V/V/T knobs, but the two volume knobs are push pull switches for individual pickup single/double coil switching

Trying to make this complicated for me? Ha.

I am still undecided on what to do right now, but I know I can fit a preamp in if I want to, so I think I'll go ahead and glue it up today so I can start working on the body shape. This one will be put aside in a few days for the build-off, so I'll have plenty of time to think about it.

Right now (and this is probably no indication of what will actually happen) I'm thinking of doing an Audere preamp. That fourth knob kinda bugs me, but I can make smaller knobs. An EMG preamp might work as well, but I would probably have to stash the battery up by the neck pickup.

 

[Jisch]

I got the insides cleaned up and put a coat of shellac on it, just to seal it up, then glue up commenced. I put two sheetrock screws in the neck pocket area and put some through the pickup covers then put it in the bag. The vacuum bag is key for this kind of glue up where there's no flat surfaces to clamp and the possibility of cracking the top if you put too much force in one place. The bass side did warp a bit after I carved it, but there was only a 1/8" gap or less and the bag seemed to squeeze that right into place. We'll know in a couple hours how well it went.

It looks like I got to the desired number of coats on the Tru Oil side and the sun is out today. So I wiped on (which is the worst way to apply this stuff) the UV cure finish, I'll let it settle and hit it with some UV in a bit, I'm sure this will not be a flat coat by any stretch, but at least it will show me the difference in color between the amber Tru Oil and the clear UV stuff. That Tru Oil side looks pretty good, the tinting is pretty minor. It looks pretty orangey in this pic, it's actually more red and less orange in person.

 

[Jisch]

I put the UV stuff out in the bright sun. BTW the bright sun today kicked this stuff hard compared to a longer time on a partially cloudy day from a few weeks ago, I had read that it would kick on a cloudy day, but probably not a northern hemisphere winter partially cloudy day.

After five minutes today it's hard as a rock. While the Tru Oil is slightly darker, it's only marginally so. I have to consider whether I want to experiment with this other stuff (or the two part stuff) on an instrument. My concern would be coating the whole thing without getting drips and/or doing only one side at a time and ending up with a seam as I don't think either of them would dissolve the first/adjacent coat.

This is pretty color accurate, it's maybe a slight bit darker than this. The left is a single coat of the UV stuff and the right is 7 or 8 coats of Tru Oil. The UV stuff left a much thicker coat. I did sand and buff the UV side as there was a lot of "stuff" in the coat, it's not as shiny as it could be if I worked a bit harder on it.

 

[Jisch]

I love it when a plan comes together. I left the ash back a bit large and didn't fully round over the front, my plan was to blend the two together once it was glued up. I wasn't 100% sure what that would look like, but now I do! It looks awesome.

I used the oscillating drum sander to leave a consistent 1/16" margin all the way around, then made a line that represented half the thickness of the body (looks like it's going to come in right at 1.75" thick) then rounded over using a shinto and scraper from the front to that middle line. Wow, it looks just how I imagined it. I'll get the rest of the body rounded over tonight.

It looks huge, but it's still pretty light. The F holes make it look so 3 dimensional, as I said before I didn't expect that aspect of the whole thing. I know I'm hiding it well, but I'm pretty psyched at how this one is coming out.

My plan is to stain the maple, but leave the ash natural.

 

[ctmullins]

Niiiiiiice.

 

[Jisch]

I ordered the EMG HZ preamp (if anyone cares) I have a BTC on my eight string and I can live with that stacked pot.

 

[5tring]

This is looking great

 

[Jisch]

This took longer than I expected, but I got most of the front shaped and the neck pocket routed.

I need to do a lot more on the horns, but it's coming along!

 

[Jisch]

I got an hour in the shop this morning, I mainly worked on the horns. I think I have the general shape done, but there's a lot of nipping, tucking and smoothing to be done. I went a bit angular with the lower horn to give it a little character, of course it will get some smoothing out, but I'm going to leave that harder edge on the swoop, I think.

I also need to figure out what to do on the back. My original thought was to do a minor roundover, but the more I shape the front the more I think it should be round. Perhaps I'll do the 1/8" roundover bit first to see what it looks like, I can always go rounder.

 

[Slidlow]

I vote to go ahead and round the back too.

 

[Jisch]

I vote to go ahead and round the back too.

ok, your vote has been counted. I still think I'm going to do a small radius roundover first. I can always go bigger.