A 5-String Multiscale ‘Headless’ DIY Bass

[Chuck Tweedy]

Nice wrap!
That is a great idea - I need to steal it.

[Jason Rodgers]

I need to put foam wrap on the headstocks of all my guitars when I'm playing them!

[Dave Higham]

I made a new router table. It’s just as basic as the other one but it’s bigger and easier to set up. So after having cut off the surplus on the band-saw, I routed the neck flush with the fingerboard.

The neck routed flush to the fingerboard and the extension (up to the neck pickup) reduced in width.

Extension reduced in thickness and the corners of the neck/fingerboard radiused. This was mostly done on the milling machine but the corners were radiused by hand using a tiny plane and sanding sticks.

Reduced the neck to final thickness where it fits into the neck pocket using the router sled I mentioned earlier.

Cut off the surplus and this end is nearly done.

[Dave Higham]

Now back to the body and a lot of router templates. I started by making a template to rout a recess for the bridge. I stuck a piece of the plan to a piece of MDF, stuck the bridge in place using double sided tape and surrounded it by strips of wood screwed down to the MDF. The MDF is big enough to serve as the pickup routing template also.

Then I took the bridge out and routed inside the strips to make the template.

I decided to make the tops of the bridge and pickups more or less parallel to the string paths, so this meant raising the template at one end. I found out how much from my CAD drawing and stuck some small blocks of the right thickness to the back of the template.

Here’s the template in place ready to route the bridge recess. I used a 16mm (5/8”) cutter and finished the corners with the 3/8” cutter from Stewmac. You can see the dowels locating the template on the body. They are a tight fit so there was no need for double sided tape to hold the template down.

[Dave Higham]

I followed the same procedure for the pickup recesses except that I hogged some of the wood out with a Forstner bit before routing. So here are the bridge and pickup routes done. The pickup routes are rather deep and I had to pull the router cutter out of the collet more than I would have liked, but I managed it. I really need a longer 5/8” and 3/8” cutter.

The tuner block is set in at a fairly steep angle so the template had to be made with some wedges under it.

This meant it couldn’t be located using the dowel pins so it had to be carefully positioned and clamped in place. I decided it would be better to do the round-over in this area before routing for the tuner block although I didn’t take any photos. It’s a ½” radius round the front of the treble side and part of the bass side. The rest will be done later.
By the way, over here round-over cutters are all funny sizes, like 6.35mm radius, 9.5mm, 12.7mm, 19mm, etc., and I’ve never heard anyone wonder why.

This is the result.

[Dave Higham]

Next was the neck pocket. (Before starting on it I marked out and drilled the rest of the holes for the neck screws.) The same procedure was used to make the template. Here the template blank is dowelled to the body and the neck is being aligned with the body. Then strips were screwed to the template butting up to the neck and the neck profile routed into the template as before.

The geometry of the bridge and body was such that if the fingerboard were parallel to the top of the body, the underside of the fingerboard would be 4mm (5/32”) above the body so I decided to set the neck at an angle and bring it down flush with the body.

I didn’t calculate a neck angle. It seems to me that there’s no point in calculating a neck angle and finding it comes to, for instance, 1.673° which would be impossible to measure accurately. This is where CAD is so useful. In my drawing I moved the neck to be flush with the body and then rotated it until a line touching the tops of the frets also touched the top of the bridge saddles in their lowest position. From this line and a line parallel to the top of the body I can draw in spacers of different thicknesses between the two lines and the CAD programme tells me how far apart to position them.

I don’t think I explained that very well, but in this photo you can see the resulting blocks glued under the template.

So after all that, this is what the body looked like.

[Chuck Tweedy]

I moved the neck to be flush with the body and then rotated it until a line touching the tops of the frets also touched the top of the bridge saddles in their lowest position

Actually, that is very clear. Just like everything you do even your language is precise and clean.
Great stuff - keep it coming.

PS - Hmmmm, 6.35mm ... that does sound familiar...

[Dave Higham]

your language is precise and clean.

Well, I do try. (Don't get me going on bad English, or even bad American , or bad punctuation, or spelling! ['No, heal is what happens after you stuck the chisel in your thumb and it started to get better. That bit of your guitar's neck is a heel dammit!'] There, I feel better now.)

Right... onward and upward...

The template for the control cavity was made by sticking a drawing to a piece of MDF and cutting the shape out by hand. Hogged out with Forstner bit; finished of with router.

The control cavity cover was made from an off-cut of the alder back.

To make a routing template for it I wrapped the curved side of it in painter’s tape; both sides and the edge. Three sides of it are straight so strips of wood were butted up to them and screwed down. A fourth strip was profiled to the same approximate curve and then spread with a layer of polyester mastic used for car-body repairs (Bondo?). This was then pushed up against the curved surface, screwed down and left to harden. When it became rubbery and started to harden I trimmed off the surplus that squeezed out.

When the mastic was hard I took off the straight strip and pulled out the control cover, and screwed the straight strip back in place.

Then I routed the template on the router table.

[Dave Higham]

Fixed the template to the body (still using the dowels) and routed the recess for the cover.

The cover will be held in place by small magnets so I stuck the cover to a piece of MDF using double sided tape and routed round it to make another template. I marked out the positions of the magnet holes and drilled them through the template and into the cover.

Then I took the template off the cover, turned it over, fitted it into the recess in the body and drilled the holes through the template and into the recess. (You’ll notice that I’d also gone round part of the back of the body with the ½” round-over cutter.)

I fitted the magnets in the cavity cover and the recess. They were quite a tight fit so I pushed them just below the surface and then wicked a drop of thin CA around each one.

I covered the inside face of the cover with copper shielding foil and stuck some temporary strips of copper foil onto the ledge where the cover sits.

[Dave Higham]

So now when the cavity cover is in place, it sits slightly proud of the back.

So I sent it through the sander a few times until it was flush. It turned out to be quite a good fit.

[Chuck Tweedy]

Okay, now how do you get the cover OFF??
Bigger magnet maybe?

[Keith VanDen Heuvel]

Excellent work on this. Along with everybody else I am following this build closely. One question regarding your cavity cover: Are you planning one having a recess in the body so that one can use their thumb or finger to lift the cover off once in place? With such a tight fit, it seems like it would be difficult to get off as it is.

[Dave Higham]

Okay, now how do you get the cover OFF??

Hooray! I left it there to see if any one would ask. (Might have known Mr Tweedy would.)

This is how.

[Chuck Tweedy]

Don't call me Mr. Tweedy, it makes me sound like an evil chicken farmer!!

[Jason Rodgers]

Nah, more like a history teacher.

Dave, I'm consistently impressed with your precision. And it's not even CNC! It makes me think, I have those tools, and if I was actually that careful and planned it out, I could do that, too! This is probably a good line of thought for me, as I may have mentioned a few unfinished projects.

[David King]

Cavity covers are always challenging. At some point you have to make them fit the best you can and that's a time consuming and fraught business that few customers seem to appreciate.

[Steve Senseney]

Nice!

[Dave Higham]

Thanks Steve.

Instead of an arm-rest bevel on the front of the body, I put a cylindrical surface on the whole of the bass half (this is why I had to vary the depth of the cavities I routed before gluing the two halves of the body together). I made this jig for the second bass I made which had a cylindrical surface on the whole of the front, but I think if I did that on this one, the treble side of the body wouldn’t be deep enough for the electronics.

Here’s an end view showing the curve on the front of the body.

I then turned it over and did the same thing on the back.

Here’s a side view showing the shape the curved surfaces make.

And one of the other side. I actually put the body back in the jig and swivelled it slightly to bring the outermost part of the upper horn in line with the widest point of the lower bout. I then routed just the upper horn so that at its narrowest point it was the same thickness as the lower bout. I didn’t take any photos of that.

[Dave Higham]

I bevelled the back in the waist, tapering the bevel right up to the end of the upper horn. The bevel doesn’t show up very well in the photo. The bevel was cut using spoke-shaves and sanding sticks and was made so the edge of the body is the same thickness from the widest part of the lower bout to the end of the upper horn.

The edge was the rounded using spoke-shaves, sanding sticks and cloth backed abrasive in the shoe-shine style to give this. The white thing in the neck pocket is a sacrificial block of wood which makes it easier to shape the area around the neck pocket without accidentally sanding or rasping the corners off.

After a lot more sanding the back now looked like this.

[Chuck Tweedy]

Yea, it was all techie geek square with hard edges till this. Now you're showing your softer side Dave.