Black Walnut lightweight...

[Andyjr1515]

It's been a while since I did a major build and now I have two! One is under wraps at the moment (mainly because it may not work ) but the other is a challenge in a different way.

I want to break the back of the under-wraps project, so it might be a little while before I make much progress on this other one but it is to try to build a lightweight body (Cort Curbow sort of light!) from a chunk of solid american black walnut.

Yes....quite

The plan is to strip a Cort's bits and just replace the body. The outline will be similar to the Cort but the carve will be something like this:




The depth of carve will be quite deep, something like two of my earlier 6 strings...one I did a few years ago in solid mahogany:






...but probably with the top of the lower bout more like the one I did in Yew:



Two reasons - firstly because I think those kind of shapes bring out grain patterns of nice woods out a treat...secondly because it takes a lot of wood (weight) out of the proceedings.

But, the Cort Curbow is made out of light plastic-type material and walnut is b*****y heavy! So I know that won't be enough.

With a two-piece (back and top) like the yew / mahogany six string above, chambering is an option. However, with a solid it's a bit more tricky. So my thought is two control chambers at the back...and both quite generous in dimensions - with chamber covers using the same walnut as the body itself. It will end up like half of a centre-blocked semi-acoustic.

Additionally, I will minimise the depth of the body to that just deep enough for the controls. It will probably end up about the same thickness as an SG. The density of the walnut SHOULD (fingers crossed) still retain the mass needed in a good bass.

To achieve the matching control panel covers, I got Kirk (great bloke) at [url="http://www.exotichardwoodsukltd.com"]www.exotichardwoodsukltd.com[/url] to bandsaw a 4mm plate off one of the blocks of the two-part body wood I bought for the project.

Balance in theory should be a big issue. Interestingly, the Cort balances beautifully...it shouldn't. The neck is set in as far as it can without the bridge hanging in fresh air, and the headstock is TINY. So, the theory (yeah...right) is that if the walnut body can be made the same weight as the Cort and have the same geometry, it will balance too!

Well, without a few challenges, where's the fun??

I'll post a shot of the timber and doner bass soon, and then there may be a long period of silence...

Andy

Edited February 12, 2015 by Andyjr1515

[scojack]

Some cracking work there Andy, that Yew is stunning especially with all the carving, looking forward to seeing this progress.
Wonder what the 'other' project is hmmmm ........
Ian

[Andyjr1515]

[quote name='scojack' timestamp='1423820205' post='2689301']
Some cracking work there Andy, that Yew is stunning especially with all the carving, looking forward to seeing this progress.
Wonder what the 'other' project is hmmmm ........
Ian
[/quote]
Thanks, Ian

So, got my hands on the donor guitar, got the walnut and the 'other' project is temporarily paused while I wait for some info and bits relating to it. So if it stays dry this week, I may be able to make a proper start on this one.

Here's the Cort:


Actually, I reckon it's a bit heavier than the owner's identical Tanglewood, which might give me a fighting chance to get the weight down enough.

First jobs are to:[list]
[*]Strip the Cort down
[*]Work out the thinnest body I can get away with compatible with the controls depth
[*]plane down my 2 walnut halves to that thickness - this will give me an idea of the figuring too...
[*]square up the join line and join the two halves
[/list]
Thanks for looking, all!

Andy

Edited February 16, 2015 by Andyjr1515

[Andyjr1515]

It was dry today so I was able to plane down the walnut halves to the initial thickness of 1.5" I'll see how the carve and weight goes - it may come down to more like 1.25" but I don't want to get it too slim for the electrics to fit...

Walnut is a nice wood to work with and these pieces have some interesting detailing in them:




Got the edges all squared up (I'm getting better setting up and using a hand plane!) and they are now in the sash clamps waiting for the glue to cure.

Andy

Edited February 17, 2015 by Andyjr1515

[alittlebitrobot]

Great. I clicked the instant I saw your avatar beside the forum link
This is really interesting.

As if prompted by the side of a cereal box, I have a couple of questions/comments.
1. Where did you get that walnut?
2. What do you plan to do with the bits of the Cort that you're not using?
3. That yew is [b]gorgeous. [/b]Being as toxic as it is, did you have any trouble working with it? Or did you take any extra precautions?

I can't wait to see more.

Edited February 17, 2015 by alittlebitrobot

[Andyjr1515]

Hi alittlebitrobot!

Thanks

The walnut came from Kirk at www.exotichardwoodsukltd.co.uk - great bloke, great website and great woods.

The old Cort body will probably go back to its owner...after all, he might not like what I do Everything else will be used for the build

And yes - you have to be very careful with yew. The wood is highly poisonous so you have to wear a mask ref dust, and be very careful where the chippings go! It's not particularly reactive ref allergies, etc, but deadly poisonous if ingested to any great degree. So chewing the guitar in frustration at the end of a bad gig will make a bad day even worse

Edited February 17, 2015 by Andyjr1515

[Andyjr1515]

I cut a template out of a large sheet of paper to try out the four options to work out which will give the most interesting figuring once its carved.

I think it's this one:



If it's dry over the next couple of days, I'll cut it out oversize ready for popping a template on to route it to final outline

[PlungerModerno]

It's true beauty will only come out with the carve, and later with the finish . . . But as it is it appears to have a lot of potential.
I'm subbin'.

[Andyjr1515]

[quote name='PlungerModerno' timestamp='1424286782' post='2694813']
It's true beauty will only come out with the carve, and later with the finish . . . But as it is it appears to have a lot of potential.
I'm subbin'.
[/quote]
Yea - I hope so

Thanks!
Andy

[rk7]

Subscribed!

RK

[HowieBass]

Andy, have you looked at photos of the genuine article, in other words Greg Curbow basses? Lots of beautiful wood combinations with those hand-built instruments. Most of these Curbows stayed in the USA; you'll find a lot of threads on them over on TalkBass.

[Andyjr1515]

[quote name='HowieBass' timestamp='1424291946' post='2694897']
Andy, have you looked at photos of the genuine article, in other words Greg Curbow basses? Lots of beautiful wood combinations with those hand-built instruments. Most of these Curbows stayed in the USA; you'll find a lot of threads on them over on TalkBass.
[/quote]

Hi, HowieBass

Yes - they are lovely. I think it's a great, great design - even the owner's budget white one made out of [s]plastic [/s]Luthite looks good and feels great on the strap, but some of the 'real' ones look fabulous

Andy

[Andyjr1515]

By the way, as an aside, when I got the walnut for this one, I also got some figured bubinga and a neck-length of ovangkol to make another bass similar in construction and size to the Warwick Thumb 4 Tribute I did for our band's bassist (below), but reshaped so as not to contravene Warwick's design registration.



The tribute I did for my pal is my favourite bass to play, looks great and I've been asked from time to time to build more. I've always turned them down - I'm keen to stay squeaky clean when it comes to registered designs (and, just in case you were wondering, I can't find any on the Cort) and so won't make a Thumb Tribute to sell, but it would be nice to be able to build something with the same 'gravitas' albeit a different shape.

I'll do a thread when I start it later this year...the first one will be MINE ALL MINE, but I could be persuaded to make some more if it's successful

Edited February 18, 2015 by Andyjr1515

[Andyjr1515]

It was dry this afternoon so I took an hour out to get the bandsaw out to cut the MDF routing template and over-size cut the walnut:





I have to sand smooth the template edges and rasp out the last bit of the lower cutaway that the bandsaw couldn't reach.

Then we can make some real progress:[list]
[*]stick the template onto the walnut with double-sided and then use a bearing router bit to get the walnut outline accurately cut
[*]route the neck pocket, control chamber & pickup chamber while I've still got flat, stable surfaces
[*]then start carving!
[/list]
On this kind of carve, I usually add a 'go-faster stripe' feature on the top horn:





It's ever so easy to do - just using a router to 'contour' the carve in steps, you just go a little deeper than normal, then when you carve, simply progressively carve away the step to nothing.

I think on the walnut, it will add a nice visual feature...as long as I don't go too deep!

As always, thanks for looking

Andy

[HowieBass]

This will be another I'll be happy to follow.

By the way, Ed Roman pretty much copied Greg Curbow's body design with the 'Caesar' bass...

http://www.edroman.com/guitars/abstract/caesar.html

... and it's the same shape with the Tanglewood 'Canyon' so I think you'll be okay using the same outline.

[Andyjr1515]

[quote name='HowieBass' timestamp='1424467089' post='2696772']
This will be another I'll be happy to follow.

By the way, Ed Roman pretty much copied Greg Curbow's body design with the 'Caesar' bass...

[url="http://www.edroman.com/guitars/abstract/caesar.html"]http://www.edroman.c...act/caesar.html[/url]

... and it's the same shape with the Tanglewood 'Canyon' so I think you'll be okay using the same outline.
[/quote]

Yeah I think you're right for this particular shape. In any case, this one is a one-off for a mate, not a commercial venture. However, if I started making and selling a few based on the Thumb construction and woods, I'd like to be completely clear of any ambiguity - hence the different shape (which I will post in another thread when I get round to doing the prototype ) . That Caesar is stunning, isn't it!

[Andyjr1515]

Took advantage of the rain stopping this afternoon to get the routing template tidied up and the body outline finish-routed.

I attached the MDF template with two sided tape (the extra strong stuff...more anon) and used my hand router with a top bearing trimmer bit to rout out the top inch, then flip it over and used a bottom bearing trimmer bit to do the final 3/4":




Getting the template off again was a challenge! I had to prise it off with a decorators' wallpaper stripping knife. The scratches will be either carved or sanded away:




Next jobs are routing the neck and pick-up pockets on the top and the control chamber on the bottom while I've got a nice stable and flat surface to work from. Then the carving starts

Andy

Edited February 26, 2015 by Andyjr1515

[alittlebitrobot]

It's coming along lovely.
I'm glad to see somebody else is taking advantage of the weather. I made the first bit of progress on my latest project for the first time in months the other day.
Thanks for the link to exotichardwoods. I'm sure that'll come in handy some day

I need to buy a router to go any further with mine but I'm glad to see it's possible to do it with one of the smaller ones. The thing is, I see a box for a bigger, plunge router in your most recent photos but I assume the hand router does just as good a job?

[Andyjr1515]

[quote name='alittlebitrobot' timestamp='1425026285' post='2702980']
I need to buy a router to go any further with mine but I'm glad to see it's possible to do it with one of the smaller ones. The thing is, I see a box for a bigger, plunge router in your most recent photos but I assume the hand router does just as good a job?
[/quote]

Hi, alittlebitrobot.

For all my other builds I've used the big JCB plunge router you can see the box of (the box is out because that's where I had kept my router bits).

I'd been looking for a smaller router for some of the smaller jobs for a while and saw a thread by a very good builder who was extolling the virtues of the Bosch GFK600, reckoning that even for some full builds its now the only router he uses. I got one, mainly for pickup slots, control chambers, neck pockets, etc, but thought I'd see how it fared with the body shape. For the smaller stuff it's great. For the outside body shape it worked fine, although I think I would recommend the optional plunge-attachment if I did it again - I think if it kicked, it could easily come out of your grip and it doesn't have a 'dead-man's button' so you could potentially drop the thing on your foot still on and spinning!

The plunge attachment is certainly on my 'to buy' list - not actually for the plunge (because the standard mechanism works just great) but to be able to have a good two-handed grip... I think with that, it will probably become my favourite router - much lighter and significantly less scary than the big one...and much less back-ache!

[alittlebitrobot]

Great. Thanks for the info.
I'm kicking myself after walking past a hardware shop that was having a sale. There was a decent plunge router going for 40 bones (£30), but I had stuff to do first. I went back twenty minutes later and it was gone.
Sick.

I hope you're making more progress with this. I love seeing it develop.

[Andyjr1515]

Routed out the neck and pickup pockets this morning, using an MDF template again:



To do the actual job on the walnut, I fitted the plunge router base to the Bosch - forgot to take a picture! - which gave much better (safer) grip when cutting the walnut.

I'm pleased with the accuracy - a nice tight but positive fit:







Next job (hopefully this week) is to route out the control chamber and then I can start the carving...

Thanks for looking
Andy

[Andyjr1515]

Decent bit of progress this morning - got the control chamber and battery routing finished so I'm now able to start the carving (my favourite part of any build )

I marked out the inner chamber for an MDF template and ball-bearing edging bit, and then then used a stepped ball bearing bit to cut the control chamber cover recess. These are the two router bits (the router body fits into a plunge-base that is out of shot). I used an MDF template also for the battery compartment:




Here's the template and inner rout complete. Note the 'blip' adding thickness for one of the screw positions:






This is the finished rout - I narrowed the inner chamber in a number of places to leave extra material where the screw fixings are - I will tidy the recess for those areas later with a small chisel:



So - carving starts soon!!!!

Andy

Edited March 4, 2015 by Andyjr1515

[Ghost_Bass]

Isn't that battery compartment too close to any bridge screws or pickup routing? I woud have putted it towards the top horn so i could keep the most wood possible on the central block to help with ressonance but i'm not a luthier and i know nothing about this science

Looking good

[Andyjr1515]

[quote name='Ghost_Bass' timestamp='1425556518' post='2708510']
Isn't that battery compartment too close to any bridge screws or pickup routing? I woud have putted it towards the top horn so i could keep the most wood possible on the central block to help with ressonance but i'm not a luthier and i know nothing about this science

Looking good
[/quote]

Hi Ghost Bass - and thanks

The outside shape and route positions are exactly per original (although the final carve will be completely different) but I can see why you think it looks a bit odd.

If you look at the pic of the original above, you see that the bridge is RIGHT at the back! I can't be sure, but I think it is to prevent neck dive - when I first saw this (and the Tangelwood equivalent which is even lighter) I thought is was a short scale, but it is a full 34". With a light body, one of the ways is to bring the neck right back and have a very small headstock...both of which are features of the original design. The long horn also places the strap button well forward, again helping it to balance. The compromise is that the sit of the bass on the strap will be different to a 'conventional' bass

Mind you, I might have that completely wrong

Andy

[alittlebitrobot]

Yeah, they're mad-looking things but I love the design and, having played a fretless 5, I really like the sound.
However, my bass-playing never extends beyond the walls of my house so strap balance is irrelevant to me. What matters is how comfortable they are on my lap, and that's where these fail, in my opinion. I found my left hand was kind of holding the neck up while playing.

Edited March 5, 2015 by alittlebitrobot