SBO 2022 - Cheaper by the Dozen - 12 String Bass

[ctmullins]

“Working around the defects” describes most of my professional career…

That fretboard is amazing!

 

[Gary_M]

“Working around the defects” describes most of my professional career…

That fretboard is amazing!

I thought those were actually undocumented features??

Yeah, I'm pretty excited about that board. That came from a piece of coco that I bought years ago, that was more or less scrap. It's been sitting on the shelf and I just wasn't sure what to do with it. But it looks like it's going to make a pretty cool looking fretboard after all.

 

[TerribleTim68]

When you say....

...and got it radiused to 12" at the router table....

Are you using a router bit to radius the face?

 

[Gary_M]

When you say....

Are you using a router bit to radius the face?

Yep, exactly. I used a radiused sanding beam to shape the fretboards on the first 2 guitars that I built. I was immediately fed up with that nonsense. I bought a variety of fretboard radius router bits and haven't looked back. The process takes about 10 minutes per board including attaching the board to the fixture. I've documented that procedure in several of my build threads, but just sorta skipped over it this time.

 

[TerribleTim68]

Yep, exactly. I used a radiused sanding beam to shape the fretboards on the first 2 guitars that I built. I was immediately fed up with that nonsense. I bought a variety of fretboard radius router bits and haven't looked back. The process takes about 10 minutes per board including attaching the board to the fixture. I've documented that procedure in several of my build threads, but just sorta skipped over it this time.

Yeah, I've read several threads and/or articles about it, probably your build threads as well. I think the only thing that freaks me out is just the sheer height of those bits and then of course the router needing to be powerful enough to actually use it. I'm not sure my benchtop table with the Porter-Cable router in it is gonna spin that puppy when the chips start flying. NowImSayin?

 

[Gary_M]

Yeah, I've read several threads and/or articles about it, probably your build threads as well. I think the only thing that freaks me out is just the sheer height of those bits and then of course the router needing to be powerful enough to actually use it. I'm not sure my benchtop table with the Porter-Cable router in it is gonna spin that puppy when the chips start flying. NowImSayin?

Well, the bits that I use are fairly narrow... no wider than a standard 1/2 or 5/8" bit. I only take very small amounts of material per pass to avoid chip out, because I like to radius after I have already cut the fret slots.

So, a standard router in a table will do just fine. The trick is to use a very square fixture to attach the board... and keep the board absolutely centered on the fixture along the long axis.

I adjust the cutter to just kiss the centerline.

Then I bury most of the cutter in the fence... I'm just taking about a fat 1/32" per pass here. For example, I make a pass on the treble side of the board, flip my fixture, then make a pass on the bass side. I move the fence back to expose an additional fat 1/32", then make the passes again... rinse and repeat until you hit the centerline.

This is the next to the last pass... (the penultimate pass, you might say? )

And this is after the final pass... ready to hit with a sanding beam, or radius beam to remove machine marks. It comes off the router table in pretty clean condition.

 

[Gary_M]

Here's the board attached to the "fixture"... it's just a glued and screwed plywood sammich. the edges are nice and square to the faces and I have centerlines scribed for easy alignment.

 

[TerribleTim68]

That's awesome. I'm kinda jelly.

 

[BishopJP]

Here's the board attached to the "fixture"... it's just a glued and screwed plywood sammich. the edges are nice and square to the faces and I have centerlines scribed for easy alignment.

Can't argue with those results! I love the two-tone fretboard!

Is there a noticeable difference in hardness in the sap wood portion of the board?

 

[Gary_M]

That's awesome. I'm kinda jelly.

Get ya some! They aren't that expensive.

Here's an Amazon link to the Yonico brand.

 

[Gary_M]

Can't argue with those results! I love the two-tone fretboard!

Is there a noticeable difference in hardness in the sap wood portion of the board?

Thanks. I'm sure there is some difference, but I haven't really tested in this case. They both feel pretty hard, but I'll check it later today.

 

[TerribleTim68]

Get ya some! They aren't that expensive.

Here's an Amazon link to the Yonico brand.

Yeah, I'll need to convince the wife that I build enough to make it worth it.

 

[Gary_M]

Yeah, I'll need to convince the wife that I build enough to make it worth it.

Just point out that if she really cared, she would care enough to see that you didn't get a repetitive stress injury from radiusing fretboards with a sanding beam.

 

[Gary_M]

Tonight I worked on getting the truss rods installed. I think with 2 rods and a strong, multi-lam neck, it shouldn't need any CF rods.

I decided that keeping the truss rods at a constant distance from the outside edge of the neck would make the process much easier. So, I got my router table set up and I verified the settings with a piece of scrap.

I transferred the stop and start points for the truss rods to the back side of the neck blank so they were very easy to see. I used the adjustable sacrificial boards on my router table fence to designate where the extent of the router bit blades were. This makes it pretty easy to start and stop at the correct spots. This method requires keeping the beam firmly against the fence at all times, especially when making the plunge cut to start.

I routed the slots in 2 passes. They turned out pretty well, I just overshot a bit on one of them.

After that, I squared up the ends of the slots with chisels and relieved extra space for the adjustment nuts. I'm very happy with the fit.

More soon.

 

[Gary_M]

A little more progress to report.

I cut the headstock angle from the blank and cleaned up the top face. Of course this will still need some wings attached. I'm still finalizing the headstock shape... having that many tuners limits the options a bit.

This is the step that is always a little scary for me. Calculating the amount to route away to allow for the drop top, the neck angle, as well as a little extra "wing" angle. The wing angle accounts for the point (closest to the nut) at which the longest body wing meets the neck (usually on the bass side of the neck). This allows for a small angle that falls away toward the end of the fretboard. If you forget this, your drop top can end up covering part of the edge of the fretboard and you will need to do some creative carving to correct this. Ask me how I know.

I should make a good drawing of this at some point, but let's just say this is all pretty fiddly for me and I often find that I've miscalculated only to correct myself at the last moment.

Normally, I can calculate the additional amount of "drop" needed at the scale line to accommodate the bridge height. (By the way, by "drop" I mean how much lower from the original "top" of the neck beam) But in this case, I'm not going to allow the full amount. The bridge is a full 19mm tall. I'd have a ridiculous amount of neck angle and the strings would be a mile off the body. So, this one will be a compromise. I'll account for a normal neck angle and then recess the bridge into the top of the body to arrive at what I hope is a happy medium.

If anyone was able to follow that narrative, you deserve an award. OK, on with more pictures; which, in the end, are fairly boring.

I perform this routing operation on my inverted pin router. So, I attach blocks to the rear of the neck beam. I set these so that I am not cutting into the final point at the end of the neck. I'll clean that up later by hand. You can see some guidelines that I've drawn on the side of the neck. These represent the end of the fretboard plane, the neck angle and the drop top thickness.

I start with the drop top thickness. This is a straight route that removes the bulk of the waste and is around 5.5mm deep.

Now, to accommodate the neck angle, I remove material from the "foot" that I left at the end of the beam.

Here is the same shot, but now I'm pushing the neck beam down to the table on that shorter foot...

Close up of the shorter foot... I have to hold this down firmly as I make my final pass. I leave the router depth set exactly the same for the next step.

And there it is. You can now see that the material removed matches that angled line on the side of the neck.

Side view

Top view

Now I can remove the foot completely, but I'll leave the excess at the end to help hold the top when I glue it.

I think I've mentioned this before, but many, many thanks to @rockhewer for helping me wrap my head around this process and introducing me to this method. You rock, Kev.

More soon.

 

[Gary_M]

Tonight I glued up the wing sammiches. These are composed of alder, black dyed poplar, mahogany and katolox on the rear. I used UF glue for this operation and used the vacuum bag for clamping duties. I use tape to keep the bundles together until the vacuum can take over. The treble side wing will get the katalox plate later, after I've cut the control cavity cover from that laminate.

More soon.

 

[TerribleTim68]

I'm jelly of the vac bag. I only have one big enough to do a couple steaks.

 

[RichterScale]

Are the bags disposable? Or can/do you clean them out and reuse?

 

[GMC]

Tonight I glued up the wing sammiches. These are composed of alder, black dyed poplar, mahogany and katolox on the rear. I used UF glue for this operation and used the vacuum bag for clamping duties. I use tape to keep the bundles together until the vacuum can take over. The treble side wing will get the katalox plate later, after I've cut the control cavity cover from that laminate.

More soon.

This is such a better way to apply veneers to large flat surfaces. If I do more volume of bass construction in the future...I'll need to invest in something similar. Thank you for sharing. I also really like your approach to fingerboard radius cutting...I think I need to investigate this approach further once my current build is complete.

 

[boxerrider]

Are the bags disposable? Or can/do you clean them out and reuse?

The bags are reusable, as long as you don't poke holes in them.
This link is as good of an entry into the rabbit hole as any.
Vacuum Bagging Basics for Veneer Work