First project: Folk Bass DIY upright

[NKBassman]

I have been wanting to take on a musical instrument project for a long time. I've been lurking in the Luthier's Corner forum and posting a few ideas here and there over the years that ultimately went nowhere. Historically I've always been more of a thinker than a doer, but I'm trying to change that and so this is kinda like self-assigned therapy homework, and I've finally convinced myself to move ahead on my first project .

A few years ago I was wanting some sort of bass instrument for the express purpose of bringing to the local Folk Festival campground for late night campfire jams and such. The name of the game at the time was to spend as little money and as little effort as possible to get something that would make enough sound to keep up with an acoustic guitar around a campfire. However, I don't much care for acoustic bass guitars... I find them overly bright and generally lacking in low end, and hardly loud enough for playing along with guitars and singers. Then I stumbled across some threads here by member @Kickass who had made a few of these folk basses using old kick drums! Brilliant and exactly the aesthetic vibe I wanted. I studied his photos and after a brief chat I fudged one together in a hurry before that year's festival.

The "body" is an old kick drum that I picked up from a flea market and reskinned with a beater-head skin. I cut a hole through the top and installed a vertical beam of multi-lam maple and mahogany through the drum, which is fixed to gusset plates at 12:00 and 6:00 inside the drum. The neck attaches to the beam at the top, and I installed two random hardware store springs that "looked about right" between the beam and the inside of the beater head to help support the downforce of the bridge. I sized everything so that it would work with a junk 34" scale electric bass neck that I had laying around and standard electric bass strings. The "tail piece" is a door hinge, two lengths of threaded rod I scavenged from a job site, and some aluminum angle to hold the ball-end of the strings . It even has a removable end-pin for playing upright or seated lol! The bridge is just a piece of 1x4 pine shaped by hand, with a small piece of wooden shim to fine-tune the action.

Overall, the project was a success! It is perfectly playable, it is loud (enough), and it actually sounds like a bass instrument. And of course, most importantly, it draws a lot of attention towards yours truly whenever it makes an appearance . It's hilariously janky and a great conversation starter.

However, it's not without a few quirks and there are improvements to be made.

1. The electric bass neck is actually very uncomfortable to play in an upright position. It's not thick enough from front to back to properly support the hand in that position, which results in a lot of cramping after a while.
2. The neck angle is too shallow, i.e. I feel like it would be more comfortable to play with the neck tilted back more and having a taller bridge. Plus that would put more down-force on the bridge, hopefully resulting in more movement of the drum head and more resultant volume.
3. It's very heavy to lug around a gigantic festival campground, drunk, in the middle of the night.
4. The tone is a bit ringy with more treble than necessary. I probably over-tightened the drum skin.

So I'd like to tackle these issues before this year's annual festival in July... my project goals are as follows:

1. Build a new neck! I've already purchased a dual-action truss rod and some carbon fibre reinforcing bars to make sure I actually move forward on the project. I've never done anything remotely this complicated before, so this will be the biggest challenge by far. Worst case I can just go back to the old neck if it all goes south. For a personal connection, I'm going to try building the neck blank using some old-growth Douglas Fir 2x4s that were removed from my 100+ y/o house during a covid renovation. I plan to use a pre-radiused fretless fingerboard from LMI.
2. Address the neck mounting angle to get more slope on the neck and more height at the bridge.
3. Strategic lightening wherever possible.
4. Have a drummer friend come over to help me tune or dampen the skin properly.

 

[NKBassman]

 

[NKBassman]

Phase 1: Disassembly

Taking it apart was significantly easier than putting it all together. Who'd have thought.
The drum itself came with enough hardware for mounting front and back heads. In the name of lightening, I removed all of the rear skin hardware. Good riddance.
I removed the existing neck and set it aside. More on this to come.
I removed the neck beam so I could work on thinning it down and lightening it. One of the screws mounting the tail piece through the drum shell and into the bottom of the neck beam sheared off when I tried getting out, but that's a problem for another day.

 

[T_Bone_TL]

I have wondered (but it's a heck of an "experiment" if it does not work) if cutting the drum in half (straight through the middle, or slightly at an angle but half & half) would work or ruin the sound. As much because you can then get 2 out of one old drum as for making it smaller and lighter.

 

[NKBassman]

Interior structure of the drum

The neck beam slides in through a hole in the top of the drum shell, between the plywood gussets top and bottom and is fixed in place with four lag bolts. The gussets are glued in with PL Premium polyurethane construction adhesive. I made the top gussets full depth of the drum so I can sit on it to play it . I'm not that heavy, but some extra bracing at the back end might be beneficial . Sadly, the LED light strings around the perimeter of the drum skin died almost immediately after installation . I'll definitely be replacing these for major late night lolz.

The existing neck

For “educational purposes”, I sanded the finish off the front of the headstock and most of the back of the neck. I made a concoction of steel wool dissolved in vinegar (iron acetate solution) to give the back of the neck a grimey played-in appearance, which is the brown mottling that you can see. The solution reacts with the natural tannins in the wood and causes them to darken. Science! I went a little overboard on sanding back the original finish, so it doesn’t really look like natural wear, but it’s all just a learning opportunity so that I know what (not) to do with the future neck.

I’m currently building up an oil finish on the back of the neck. After stripping the sticky poly finish off and applying the vinegar solution, I sanded to 220 and then began wet sanding with Watco Tung Oil, allowing each coat to cure for a day before applying the next one with finer grit sandpaper. The third coat went on yesterday using 000 scotchbrite to rub in the oil, and it’s so smooth! I think I’m going to burnish it back to satin and leave it there for the time being. Headstock will get a similar treatment eventually, but I’m still debating whether to apply a decal or something first.

The black specs on the face of the headstock are a result of using steel wool in the sanding process, which left little bits behind that corroded and stained the wood. I don’t care, but I’ll stick to sandpaper and scotchbrite pads instead for any future finishing.

 

[NKBassman]

I have wondered (but it's a heck of an "experiment" if it does not work) if cutting the drum in half (straight through the middle, or slightly at an angle but half & half) would work or ruin the sound. As much because you can then get 2 out of one old drum as for making it smaller and lighter.

@Kickass has built a number of these and might be able to say what effect a shallower drum would have, but his guidance to me said to use the deepest drum you can find.

 

[NKBassman]

The Neck Beam

5-ply construction of maple and mahogany glued up with plain old wood glue IIRC. I used S4S boards from Lowes and thinned the middle ply maple board down using a friends planer to get the final width dimension that I wanted (essentially matching the heel of the neck). This beam is extremely heavy! I’m in the process of hogging out some material, but overall the weight loss is going to be negligible in the grand scheme. More just experimenting with new tools than anything else. I am also going to take some of the depth off of the block at the top as it’s way bulkier than it needs to be. This will probably get a few coats of tung oil as well.

The mounting block at the top is necessary to get the neck mounting surface out in front of the rim of the drum. The face was cut at an angle and is actually reasonably flat and square to the sides... can't remember what I used to cut it but it almost certainly wasn't anything fancy. Very impressive, younger self. I'm going to take at least two inches off the back of this area to lighten it up, and might plug and re-drill the holes for the neck bolts... they're pretty sloppy and there's a little too much horizontal play in the neck. Since the neck bolt holes are drilled perpendicular to the neck heel, I'd need to redrill them anyway if I change the angle of the mounting face to get more slope on the neck.



New carving tools. Yes the guard is back on the grinder since I took this photo.

 

[NKBassman]

Now is also probably a good time to point out that I don't have a woodshop lol. I'm not a carpenter by any stretch of the word (Civil Engineer by trade), but I have been doing various finishing works around my house for years now. I have a fine collection of basic homeowner-grade tools, but nothing for planing, carving, or shaping a neck with any degree of precision. I do have access to a planer, jointer, and table saw at a friends house, but I want to be smart about how I approach the neck design and construction to minimize leaning on other people. Plus, at the end of the day I want it to look homemade because it IS homemade, so at least I've got that going for me in that I have no intention of trying to make it look like a professionally built musical instrument.

I'm in the process of designing the new neck in autocad, as time allows. This will help me plan the build before ever making a cut. Another friend of mine has a proper upright bass, and he's going to send me a few neck measurements to help define the profile, which I plan to carve using the facet method. I got the cheapest truss rod I could find so that I won't care as much if I screw it up, and some .25x.25" carbon fibre bars to help stabilize the neck since this thing is intended to be hauled around outdoors, abused, and put away wet when the sun comes up.

 

[Bruce Johnson]

View attachment 5048921

Oh boy, this brings back memories......An instrument almost exactly like this gave me my start into the world of Lutherie...and Bluegrass music.....back in 1990. At that time I owned a couple of basses and had been tinkering with them a bit. I had two Ampeg Scroll Basses, two Rickenbackers, and two Carvins. I'd been playing rock in some garage bands. I had a nice home workshop and was an experienced machinist/fabricator/engineer.

I was working at Disney. There were a couple of guys who got together at lunchtime in one of the woodworking shops, playing bluegrass music. Banjo, mandolin, guitars, wailing away in the sawdust. But no bass player. I wandered in and sat around, listening and talking to them. I told them I was a bass player. Steve, the banjo player, pointed in the corner and said "Can you play that?"

Almost exactly like yours, except it was green. A bass drum with a neck attached. Steve was the foreman of the woodshop and he had built it for fun. I climbed on it and started thumping away. The band was called Sawdust, and eventually evolved into The All Digital String Band. We played bluegrass together for 30+ years. Eventually doing some real gigs and a few studio recordings. But mostly just playing together once a week on someone's back porch. Real, genuine fun music. Sadly, the two main members of the band passed away last year.

I thumped away on that bass drum banjo for a few weeks. It was playable, but wasn't very comfortable. It got me thinking.....Could I make a Real Bass Banjo?......

In 1992, Banjozilla emerged:

Bass Banjo

And that got me started in my whole career as a Luthier. As a side business during the '90's, and full time since then.

But I sure remember Steve's bass drum banjo.

 

[NKBassman]

Thanks for chiming in @Bruce Johnson! The Banjozilla cart would sure be a game changer here! lol

This is the neck project that I messaged you about last week. I've decided to try building my first neck for this project and really appreciate the picture journal of the neck builds on your Scroll Bass website. I look forward to pestering you with questions over the next few months.

 

[NKBassman]

Is there any reason why I couldn't use a large radius roundover bit to get the general shape of the back of the neck, instead of facet carving? I guess it wouldn't allow you to vary or taper the profile along the length of the neck, but maybe that doesn't matter to me for my first attempt. Might be more of an order of operations issue between cutting the width and thickness tapers, cutting the roundover, and attaching the pre-radiused fingerboard.

showing roughly the concept dimensions at the heel:

 

[Bruce Johnson]

Is there any reason why I couldn't use a large radius roundover bit to get the general shape of the back of the neck, instead of facet carving? I guess it wouldn't allow you to vary or taper the profile along the length of the neck, but maybe that doesn't matter to me for my first attempt. Might be more of an order of operations issue between cutting the width and thickness tapers, cutting the roundover, and attaching the pre-radiused fingerboard.

showing roughly the concept dimensions at the heel:

View attachment 5049178

Yes, you can shape the back of a neck using a radius router bit....Fender's been doing it for about 70 years. In a production line, it's fast and cheap. Which is why Leo did it. But, it really limits and compromises what you can do with the neck's shape.

Almost all instrument necks taper in width and in thickness. On nicely shaped necks, the radius varies going down the length of the neck, and it also varies going around the neck. A router bit can only cut at one radius. You can play around with angling the path of the router in two axes, but the bit still cuts a single radius. The shape ends up as a weird flattened oval thing that isn't really very comfortable. Like, ahem, Fender necks. (Sorry!) That's why we Boutique Builders hand shape our necks, to get those varying radiuses. And they do feel better.

And I should point out that The Varying Radiuses could be a band name.

If you are making a one-off neck, trying to shape most of it with a radiused router bit is tricky and will take more time than you think. I know, I've done it.

You should just hand shape it by the facet method. That will be faster and will give you a better result. And you should learn to shape necks, as preparation for future instrument projects. This neck sounds like a great candidate to learn on. It's going to be thick and chunky and not real critical.

 

[NKBassman]

You should just hand shape it by the facet method. That will be faster and will give you a better result. And you should learn to shape necks, as preparation for future instrument projects. This neck sounds like a great candidate to learn on. It's going to be thick and chunky and not real critical.

Thanks for the advice. I’ll try it by hand first.

And I should point out that The Varying Radiuses could be a band name.

Shouldn’t that be The Varying Radii?

 

[Bruce Johnson]

Thanks for the advice. I’ll try it by hand first.


Shouldn’t that be The Varying Radii?

I guess you'd have to ask their pronouns?

 

[NKBassman]

We had a few young guests arrive at Mrs Bassman’s Foster Cattery & Guest Home For Wayward Kitties today. Turns out Simon and Garfunkel here are not terribly fond of power tools, so I was left using hand tools tonight.



I gave the back of the old electric bass neck a rub down with a brown paper bag and I really love the feel of it! I might even be tempted to do this on one of my Fender basses some day. Other than finishing the face of the headstock I think that’ll be it for this neck for the time being. Ideally it won’t even be going back on if the new neck comes out playable.

I had half an hour to accomplish something, but without making too much noise or toxic fumes I was pretty limited. So I did some relief cuts on the neck beam with the ol’ $10 Stanley plastic mitre box saw. Worked pretty well, actually.


After a bit of “gentle” “manual persuasion”, it’s ready to get hogged out with the grinder.

 

[Tim Skaggs]

I notice there is only one head on the body (drum). I can’t tell you specifically how to do this, but there would be a way to tune the vessel of the drum with another head and a port in that head. It would be similar to porting a speaker cabinet to a specific resonant frequency, but the driver would be the solid head being driven by the strings. It might take some trial and error to get the port diameter and port depth (length) to the optimum for volume, but it might be possible to get significantly more volume out of the “body”. By tuning the drum as an enclosure, you might also reduce some of the high end you mention. String type could also increase volume and reduce “brightness”.

 

[definenredefine]

This is a very cool idea/project. Definitely following.

 

[Kickass]

I have wondered (but it's a heck of an "experiment" if it does not work) if cutting the drum in half (straight through the middle, or slightly at an angle but half & half) would work or ruin the sound. As much because you can then get 2 out of one old drum as for making it smaller and lighter.

From my experience and understanding of physics I believe the depth of the drum is what gives power to the bottom end, deeper the better. I have looked at adding a horn or folded baffle to the rear of the drum to help with bottom end. The easiest way is to join 2 drums together and I have tried this with good effect but it makes for an unwieldy bass.

 

[Kickass]

I have been wanting to take on a musical instrument project for a long time. I've posted ideas in this forum here and there over the years that ultimately went nowhere. Historically I've always been more of a thinker than a doer, but I'm trying to change that and so this is kinda like self-assigned therapy homework, and I've finally convinced myself to move ahead on my first project .

A few years ago I was wanting some sort of bass instrument for the express purpose of bringing to the local Folk Festival campground for late night campfire jams and such. The name of the game at the time was to spend as little money and as little effort as possible to get something that would make enough sound to keep up with an acoustic guitar around a campfire. However, I don't much care for acoustic bass guitars... I find them overly bright and generally lacking in low end, and hardly loud enough for playing along with guitars and singers. Then I stumbled across some threads here by member @Kickass who had made a few of these folk basses using old kick drums! Brilliant and exactly the aesthetic vibe I wanted. I studied his photos and after a brief chat I fudged one together.

The "body" is an old kick drum that I picked up from a flea market and reskinned with a beater-head skin. I cut a hole through the top and installed a vertical beam of multi-lam maple and mahogany through the drum, which is fixed to gusset plates at 12:00 and 6:00 inside the drum. The neck attaches to the beam at the top, and I installed two hardware store springs between the beam and the inside of the beater head to help support the downforce of the bridge. I sized everything so that it would work with a junk 34" scale electric bass neck that I had laying around and standard electric bass strings. The "tail piece" is a door hinge, two lengths of threaded rod I scavenged from a job site, and some aluminum angle to hold the ball-end of the strings . It even has a removable end-pin for playing upright or seated lol! The bridge is just a piece of 1x4 pine shaped by hand, with a small piece of wooden shim to fine-tune the action.

Overall, the project was a success! It is perfectly playable, it is loud (enough), and it actually sounds like a bass instrument. And of course, most importantly, it draws a lot of attention towards yours truly whenever it makes an appearance . It's hilariously janky and a great conversation starter.

However, it's not without a few quirks and there are improvements to be made.

1. The electric bass neck is actually very uncomfortable to play in an upright position. It's not thick enough from front to back to properly support the hand in that position, which results in a lot of cramping after a while.
2. The neck angle is too shallow, i.e. I feel like it would be more comfortable to play with a taller bridge. Plus that would put more down-force on the bridge, hopefully resulting in more movement of the drum head and more resultant volume.
3. It's very heavy to lug around a gigantic festival campground, drunk, in the middle of the night.
4. The tone is a bit ringy with more treble than necessary. I probably over-tightened the drum skin.

So I'd like to tackle these issues before this year's annual festival in July... my project goals are as follows:

1. Build a new neck! I've already purchased a dual-action truss rod and some carbon fibre reinforcing bars to make sure I actually move forward on the project. I've never done anything remotely this complicated before, so this will be the biggest challenge by far. Worst case I can just go back to the old neck if it all goes south. For a personal connection, I'm going to try building the neck blank using some old-growth Douglas Fir 2x4s that were removed from my 100+ y/o house during a covid renovation. I plan to use a pre-radiused fretless fingerboard from LMI.
2. Re-do the neck mounting angle to get more height at the bridge.
3. Strategic lightening wherever possible.
4. Have a drummer friend come over to help me tune the skin properly.

Thank you for referencing me!
Here are some of my observations and solutions.
My neck brace was cut with a 7degree angle for the neck join. Also I allowed for some movement in setting the angle by using the top fixing inside the drum as a pivot and adjusting the bottom fixing to get the preferred angle.
I use a set of wheels/trolley/sack barrow if travelling far from the vehicle.
I like to use a drum skin with a double layer around the edge. It helps mute ringing notes. Gaffa tape would do the same. Not sure what these are called.
I'm not sure a properly tuned head will make much difference but may make some notes ring more. I have detuned a number of tensioners to remove resonances. Hot days make the skin soft so tuning changes and rattles can appear. I have got my band to move out of the sun when we busk.

Good luck!

 

[Kickass]

I use a kevlar drum pad on the drum skin, under the bridge. The bridge is between 7cm and 8cm tall.
I use nylon cored, low tension strings.

The old site I made to help others may not be working at the moment but there are some images here: Home Bass
There is a Facebook page for the bass.