Electric Double Bass Build

[ihasmario]

Tonight I finished sanding the neck flush to the fretboard. It's sweet. There's a few things that the neck still needs to have done for it, if I feel the need. For example, the heel of the neck isn't actually flat (which means that without a body attached to it, the neck can't stand up like it should, but some cellos and double bases actually have an angled heel for flare I guess).

The fingerboard looks straight. Everything looks good. I used a cuetip and some acetone and some sandpaper to work away at the excess glue I didn't manage to scrape off in time. There's a very small gap (less than a fingernail) down the bottom of the fretboard on one side where there wasn't enough clamps (by virtue of it being impossible to fit any clamp I own on that section, and the weight not bieng quite heavy or even enough). I filled the gap with timbermate before and sanded it back, but I think some of it didn't take or maybe I sanded it out in chunks a bit. I'm not sure, but you have to look really close to notice, and I think I will be able to fix that flush later without affecting anything.

The neck has been restained. I've come to like the unfinished peg box. I'm contemplating making the ebony darker - but I dunno, being the kind of off black/brown that it is, it gives the instrument an even more rustic look. There's a stray glue spot or two that managed to find their way on to the fretboard (no idea how) that I've gone at with a bit of acetone and a cuetip and some fine sandpaper, but at the end of the day I dont want to take anything too course to the fingerboard right now. If I can get the glue smooth - or off - then I'll be sitting pretty as far as that goes.

I have to drill the peg box and create the boosters. Both which require some handy work I might not actually have, but I will give them a go first.

After that I can actually start setting up and finishing the surface of the instrument.... Which means I also need to choose what oil (or maybe poly) to use. I'm leaning towards one of the oils you can buy large quantities of fairly easily (like danish oil).


Pics of the flush neck tomorrow

[ihasmario]

For now, here's a 2d Picture of the design I am more or less following and what I expect to produce. Obviously I won't be able to produce some sweet futuristic round edges on the green boosters, however I will be trying to design something that flows upwards (kind of like what you'd expect to see on a piece of furniture, hopefully).

The green bit on the top is hopefully going to work like half a mortise and tenon join (as in, it will have a little shelf inside for the neck to sit and be glued to. I'm contemplating designing a way to bolt the neck from the back of said joint (into the heel of the neck) so maybe I can put the banjo into two pieces for easier transporting, or maybe only bolt the green part to the bass. Would be convenient!

Looks futuristic here. Will look rustic in real life, I guess.

If I can be bothered doing a 3d drawing, I will go ahead and edit this post and add it.

[ihasmario]

Here are some updates on the booster. Currently in pine - not sure if I have the funds to spare on this project to do it in anything other than pine if I need to get another tool to make it work.

I need to get more wood to test it. It's going to be 5 planks glued wide, with outer ones sticking up over the top (shown), but sloping up to follow the contour of the neck - probably need to buy a wood rasp to do that. Coping saw is too difficult on such a small object.

Difficult to get pics to look at the scale. Right now the drum has one ring on it, just to check for width. The wood is sloping out - just so I could balance it to take a pic as part of it isn't glued yet.

I'm tempted to add some more wood to tip the weight of the bass closer to the center, but it raises concerns about weight on the drum (I may need to add some internal supports given the weight of the neck and booster)... I think as it is with just the 5 planks the booster may look a bit narrow.

I need to work out how to do some shaping on the planks to make sure it's not just random planks of wood, but actually a nice little booster.

In the pic height I couldn't hold both sets of three planks that are glued together (because I didn't cut them to the same size - more on that later)

Thanks guys.

[FrankenWashie]

Too cool! Are you going to build that 'booster' to the full depth of the neck heel and carve the shape to match?

[ihasmario]

Too cool! Are you going to build that 'booster' to the full depth of the neck heel and carve the shape to match?

Depth yes - I simply couldn't hold it all there while taking the photo - I was just using it as an opportunity to check how tall it would be, and also check the scale length is still set correctly after I had to saw some more off the blocks.

With regards to shape, I'm hoping to shape it so it matches well. I'm not sure how well I will do with that though, because everything short of cutting is basically hand sanding (I can't find my wood rasp so I have to go buy one probably).

As it stands in the first pics on the floor, there's only two more of the outside planks to add to make it cover the majority of the neck heel (basically up to the ring on the drum). My woodworking skills are absolute novice, however, so I don't expect anything great.

[ihasmario]

I need some woodworking help.

I'm trying to cut this section seen out of a piece of wood (sorry it's blurry). So I have a part of the block that is thinner than the rest.

I can't for the life of me work out a way to do this well. It's about 2-3mm thick and right now I'm using a coping saw.

I've tried sanding (too slow), block plane (can't for the life of me get it to chip things down).
....

[vh2580]

If you dont have a better saw You could clamp some wood alongside the line you want to cut on each side and use as a bit of a guide for your saw to run along, not perfect but may help and will speed up your cutting.

[ihasmario]

I've managed to do two of the mayyybe four required planks that have the off-cut, however I've run into a separate but equally pressing problem...

The neck heel is tapered on two axes: the heel is fatter as it gets closer to the neck, and the base of the heel is fatter than half way up.

I've decided for the moment to try and sand my way down to match the contour of the neck, using the spare offcuts as a wedge where necessary, however I am curious as to how I would trace out these areas onto the plank that needs to follow the surface...

Would it be correct to hold the top edge of the tapered surface against the base and cut in the angle as a starting point, followed by the long edge of the plank?

[ihasmario]

Another question - because I don't have the right tools to get such a large surface perfectly straight, or perfectly sloped - what's the best way to fill the gaps that will exist between the sections and the heel of the neck (and later the drum shell)?

Extra glue?
Timbermate?

[ihasmario]

Well, the build is obviously on hold until I get some time to go and see someone who can help me build the booster.

The neck heel is sloped in a way that I don't have the skill to match.