Trying some experiments

A place where you can let us see your finished instruments in all their glory.

Moderators: kiwigeo, Jeremy D

Post Reply
User avatar
Mark McLean
Blackwood
Posts: 1084
Joined: Thu Apr 10, 2008 2:03 pm
Location: Sydney

Trying some experiments

Post by Mark McLean » Thu Feb 11, 2021 10:32 pm

An alternative title for this thread would be “polishing a turd”.

Some of you might remember this episode from back in 2009. There was a chap named Vic who was into guitar building, but not known to us on ANZLF. He died and his wife was selling off the contents of his shed on EBay. We had a good chat about it here:
http://www.anzlf.com/viewtopic.php?f=1& ... dow#p17595

One of his things that I got was a cardboard box containing a half-built 12-string, and spare parts that looked like it was some sort of a kit. I paid about $50 for it – but it wasn’t a great buy. At first I couldn’t work out what type of wood it was, but pretty soon I realized it wasn’t wood at all. The back, sides and top were all HPL (high pressure laminate, i.e. Laminex, just like kitchen benchtops) with a faux-wood appearance. I put the kit together but it didn’t sound too good, and it wasn’t long before the top bellied up and then the bridge pulled off. It has hung on my workshop wall as a “decoration” for many years.

Recently I thought I would have a bit of fun rebuilding it, and using it as a test chassis for a few ideas I have been wanting to try. I put it together quick and dirty, with little regard for cosmetic appearance, and included every new idea that I could think of, just to try them out. The build included:
1. Internal flying-buttress bracing with CF rods
2. New redwood top with falcate bracing
3. Scoop cutaway
4. Fan-fret multiscale (about 26.4” bass, 24.7” treble)
5. Bent top arm bevel – like Mike Doolin used to do
6. Some funny looking features like a slanted oval soundhole, half-slotted headstock
7. And I thought why not make it a 7-string.
The HPL back and sides were really ugly so I just painted them black with some hard-wearing laminate paint designed for kitchen cupboards. The rosette, scoop and bindings are tiger myrtle and are not too perfect. I braced the top pretty lightly, deliberately not capping the falcate braces with CF, but instead I laminated CF into the braces. I wanted to make a box that was rigid because of the buttress rods – but a top that was pretty responsive. Here are some pictures.
P2070699.JPG
P2070699.JPG (154.97 KiB) Viewed 9966 times
The falcate bracing is offset to account for the sloping bridge. I followed the pictures that Martin posted of his multiscale falcate. That worked out OK, but then I ran into trouble with the bridge. I made a pinned bridge with 7 pins and had to juggle the spacing in relation to the main falcate braces. I tried to put 3 pins between the main braces and 2 on either side. But I miscalculated the distance and ended up with the string spacing a bit too wide and the outside strings running too close to the edge of the fingerboard. Then I couldn't bring the pin holes any closer together because that would have them hitting a brace. So I ended up making a new pinless bridge, which is a bit rough looking but works. After I initially strung it up with 7 strings (a low B 7th string) I then decided I didn't like that. The string spacing was a bit too tight (neck width at the nut is 1 13/16") and I found I don't really know how to play a 7-string anyway. Made a new 6-string nut and that is how it is set up now, but it could easily go back to 7 strings if I wanted.

First impressions - It isn't pretty but it sounds pretty good. I quite like the arm bevel, I am less certain about the scoop. The multiscale is good with heavier strings (13-58 on it at present) and the bass sounds great tuned down to D or even C tunings. I will post some technical details about frequency responses, deflection testing and bridge rotation later. I wonder if Vic would have liked it?
Attachments
structural bracing.JPG
structural bracing.JPG (128.1 KiB) Viewed 9966 times
P2070721.JPG
P2070721.JPG (113.44 KiB) Viewed 9966 times
P2070715.JPG
P2070715.JPG (119.77 KiB) Viewed 9966 times
P2070703.JPG
P2070703.JPG (147.25 KiB) Viewed 9966 times
P2070701.JPG
P2070701.JPG (180.83 KiB) Viewed 9966 times
P2070709.JPG

User avatar
Mark McLean
Blackwood
Posts: 1084
Joined: Thu Apr 10, 2008 2:03 pm
Location: Sydney

Re: Trying some experiments

Post by Mark McLean » Thu Feb 11, 2021 10:42 pm

This is what it used to look like.
Attachments
hpl 12 string2-1.jpg
hpl 12 string1-1.jpg

Dave M
Blackwood
Posts: 595
Joined: Tue Jul 15, 2014 6:44 am
Location: Somerset UK

Re: Trying some experiments

Post by Dave M » Fri Feb 12, 2021 4:00 am

Well that was a fun project. And getting a decent sounding, playable instrument out of the remains is very impressive.

Cheers Dave
------------------
Dave

User avatar
lamanoditrento
Blackwood
Posts: 585
Joined: Thu May 05, 2016 9:50 am

Re: Trying some experiments

Post by lamanoditrento » Fri Feb 12, 2021 9:58 am

Wow there is a lot going on there Mark. Great that you go good sounding instrument. How do you like the multiscale? I've yet to attempt that. Any pics of your skew falcates? I too am unconvinced on the scoop but do them anyway :P
Trent

Jack
Gidgee
Posts: 8
Joined: Tue Apr 14, 2020 2:09 pm

Re: Trying some experiments

Post by Jack » Fri Feb 12, 2021 4:48 pm

Love it!

It plays and sounds ok and looks pretty cool too. That's a winner!

Jack

User avatar
Mark McLean
Blackwood
Posts: 1084
Joined: Thu Apr 10, 2008 2:03 pm
Location: Sydney

Re: Trying some experiments

Post by Mark McLean » Sat Feb 13, 2021 10:04 pm

Thanks for the comments.
Trent, I have searched in vain for a photo that I thought I took of the bracing - but I can't find it. But if you look at Martin's epic thread here you will see what he did for his multiscale build (picture about halfway down), and I essentially copied that idea.
http://www.anzlf.com/viewtopic.php?f=25 ... ale#p84636
My bridge is angled about 24 degrees off perpendicular to the midline. I therefore took the layout of the main falcate braces that I would normally have used and rotated their axis by that amount. Of course, the bridge plate is also slanted.
An interesting thing that I did not initially anticipate is how much this changes the stiffness of the top. We know that the bridge is a very stiff brace on the soundboard - but it is usually entirely a cross-brace. When you glue it at an angle like this it also stiffens the top in its long axis. While I am building I measure top deflection while it is a free plate, and then after the box is closed, and again after the bridge goes on. I usually find that gluing the bridge on makes very little difference to the top deflection because most of the bending occurs in the long axis. However, in this guitar the addition of the bridge reduced the top deflection by 30%. Also, as you might expect, this angled bridge has less bridge rotation under string tension than you normally expect to see. About half as much as I measure in a comparable dreadnought (I have measurements from a D18 and also a Taylor GS for comparison). So, the change in geometry probably results in some significant changes to how the soundboard behaves. I have not set up to do Chladni patterns - but it would be an interesting thing to compare a fan-fret to a standard guitar.

Here is the frequency response pattern to tap testing in the completed guitar - compared to a D18. Lower main air is probably from the bigger sound hole. Lower top frequency might be the stiff sides from the flying buttress bracing. I don't have much expertise in these and would be interested in comments by the wiser ones.
tops frequency.jpg

User avatar
Mark McLean
Blackwood
Posts: 1084
Joined: Thu Apr 10, 2008 2:03 pm
Location: Sydney

Re: Trying some experiments

Post by Mark McLean » Sun Feb 14, 2021 12:29 am

Trent, you also asked how I liked the multiscale? I really enjoyed building it (this is only my second one), and when playing the finished guitar I really appreciate its advantages. Playing it is absolutely natural feeling and you hardly even notice the difference. It is very ergonomic for your left hand position. It really shines if you use low pitched alternate tunings because the longer scale length on the bass strings prevents them from getting too slack and flubby when tuned down.
As I described, it is a bit tricky with falcate bracing if you want a pinned bridge because of the challenge in positioning the pins between the primary braces. It would be easier to do with X-bracing.

Here are a couple of pictures of the method that I developed for slotting the board, manually. I have two sawing guide strips made of right-angle aluminium. I cut slots (bandsaw) in them for the fret intervals of the two different scale lengths that I want - one for the bass side, one for the treble side. I thickness and taper the fretboard blank, mark the centre line, and place the strips on either side secured with double sided tape. Arrange them so that the slots for the eighth or ninth fret line up opposite each other (i.e. in this example the 9th fret slot will be at right angles to the centre line) and then clamp it to the bench. A fretting saw can then run between the equivalent slots on each side and cut the slots in a pattern that fans out either side of the perpendicular slot.
IMG-0456.JPG
IMG-0455.JPG

User avatar
lamanoditrento
Blackwood
Posts: 585
Joined: Thu May 05, 2016 9:50 am

Re: Trying some experiments

Post by lamanoditrento » Mon Feb 15, 2021 10:05 am

The multiscale fretcutting jig is clever!
Trent

User avatar
kiwigeo
Admin
Posts: 10582
Joined: Sat Sep 29, 2007 5:57 pm
Location: Adelaide, Sth Australia

Re: Trying some experiments

Post by kiwigeo » Tue Feb 16, 2021 6:07 pm

Multiscale is a pain in the arse!!!! My multiscale Gore style monster took 2 years out of my life!! :?
Martin

User avatar
Mark McLean
Blackwood
Posts: 1084
Joined: Thu Apr 10, 2008 2:03 pm
Location: Sydney

Re: Trying some experiments

Post by Mark McLean » Tue Feb 16, 2021 9:59 pm

So Martin, what caused you the headaches in doing a multiscale?
Although I would not do it again with a falcate bracing system, I think an X-brace or some sort of fan brace (i.e. any system that doesn't have the braces crossing the bridge plate) would make the body build and the bridge placement no harder than a standard acoustic build. The other hassle is the headstock scarf joint. Because the nut is on an angle across the neck rather than perpendicular you have more complex geometry at the scarf joint. But it is manageable. I found all other aspects to be pretty much standard - unless I am forgetting something.
Martin I know you are a lot more precise and OCD about your builds than I am. I suspect Trent is more like you in that regard, so you better warn him of any other issues, otherwise I will encourage him to just go for it.....

User avatar
lamanoditrento
Blackwood
Posts: 585
Joined: Thu May 05, 2016 9:50 am

Re: Trying some experiments

Post by lamanoditrento » Thu Feb 18, 2021 9:53 am

I'm all about the pinless bridge these days Mark :lol:
Trent

MBP
Blackwood
Posts: 180
Joined: Sat Aug 20, 2011 3:48 pm

Re: Trying some experiments

Post by MBP » Fri Mar 05, 2021 8:16 am

Nice rebuild. I met Vic a fair few times as he was mates with my dad. I’ll make sure I show him.

User avatar
Mark McLean
Blackwood
Posts: 1084
Joined: Thu Apr 10, 2008 2:03 pm
Location: Sydney

Re: Trying some experiments

Post by Mark McLean » Fri Mar 05, 2021 8:34 pm

Thanks Ro. I am sitting here playing that guitar now and giving a thought to Vic - even though I never knew him. It is nice to think there is some connection.

Post Reply

Who is online

Users browsing this forum: No registered users and 41 guests