New Koa and Spruce

Construction and repair of Classical Guitar and related instruments
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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Wed Jul 16, 2014 6:24 pm

James Lister wrote:Beautifully clean work as ever, Peter.

One question - do you use the Deft to get a cleaner edge when routing the binding rebates?

Errr.. one more question - do you use Deft for anything else?

James
Thank you James.
Yes, for that reason exactly. I used to do a few passes with shellac, but I find the Deft is so much thicker it really helps when routing across end grain. That protection helps when roping on bindings and cleaning up the glue also. Scrapes off easily when leveling bindings. Just stinks to high heaven. I don't use it anywhere else.

riffmeister
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Re: New Koa and Spruce

Post by riffmeister » Wed Jul 16, 2014 10:04 pm

Peter Oberg wrote:
riffmeister wrote:Looking good!

What is Koa like on the back and sides, sound-wise?
I imagine somewhere between maple and Indian rosewood, but that's overly general. Same family as Australian Blackwood, and Australian makers use that wood a lot. So much depends on the top and how it's braced, body depth, bridge design, etc. There's no question in my mind that koa will make an outstanding sounding instrument. Clearly not as hard as Indian rosewood, plus the sides are lined with cypress, so I expect the sound to be a bit less bright than rosewood, but very round and sweet, especially with the spruce.
Thanks for your thoughts, Peter.

Which of the three neck/headstocks will you use with this guitar?

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petermc61
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Re: New Koa and Spruce

Post by petermc61 » Thu Jul 17, 2014 1:06 am

riffmeister wrote:
Peter Oberg wrote:
riffmeister wrote:Looking good!

What is Koa like on the back and sides, sound-wise?
I imagine somewhere between maple and Indian rosewood, but that's overly general. Same family as Australian Blackwood, and Australian makers use that wood a lot. So much depends on the top and how it's braced, body depth, bridge design, etc. There's no question in my mind that koa will make an outstanding sounding instrument. Clearly not as hard as Indian rosewood, plus the sides are lined with cypress, so I expect the sound to be a bit less bright than rosewood, but very round and sweet, especially with the spruce.
Which of the three neck/headstocks will you use with this guitar?
I am sure you can choose whichever one you'd like Riffy!! :-)

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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Thu Jul 17, 2014 1:36 am

riffmeister wrote: Thanks for your thoughts, Peter.

Which of the three neck/headstocks will you use with this guitar?
The one in the second group of photos on the first page, with the Brazilian rosewood head piece that is relief carved and stippled.
p

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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Fri Jul 18, 2014 10:15 pm

There are four components to the fixture for shaping the neck/heel end to match the curvature of the body. (1) This plywood has a bearing set in an aluminum bar let into it.
Image

(2) The sanding drum has a pin that seats in the bearing, and the other end chucks in the drill press.
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(3) The second piece of plywood has the 'curb' that the sled will ride against.
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(4) This is the sled. HInges at one end, slotted aluminum and turn screws at the other end allow the angle to be adjusted.
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The neck in the sled ready to be sanded.
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Neck/heel and body have been mortised for the Baltic birch tenon.
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Checking the fit.
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Laying out the heel end shape.
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Pre-carving the heel end of the neck.
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More carving. I could not live without my Japanese paring chisel.
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Final check of the fit.
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The clamping setup.
Image

Bottom bar clamp has a negative heel shape block screwed to it.
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The ply piece with cork on it is screwed to the bottom bar clamp.
Image

iim7V7IM7
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Re: New Koa and Spruce

Post by iim7V7IM7 » Sat Jul 19, 2014 12:16 am

Peter,

Thanks for sharing the fixturing and joinery.

:-)
2015 - John Buscarino, 650 mm, Carpathian Spruce/Honduran Rosewood
2014 - Peter Oberg, 640 mm, Western Red Cedar/Black Cherry

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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Tue Jul 22, 2014 8:57 pm

Not as entertaining as the double top thread, or the Ruck for sale thread, but here's the latest.

The neck ready for the fingerboard. Two pins locate the board, one at the first fret and another at the 13th, just to the right of the spline.
Image

Marking the board where it meets the sound hole edge. Going to do a 20th fret.
Image

Template and finished end of the board. I'll fill the bass side of the 20th fret later.
Image

Showing the neck and upper bout in plane. Neck angle is forward.
Image

A little hard to see here, but the fingerboard is a straight line right to the sound hole.
Image

Last check on the fingerboard alignment relative to the center line.
Image

The clamping set up. I love wooden screw clamps.
Image

Clamping above the 12th fret. The middle larger C clamp has an angled caul that fits to the foot.
Image

iim7V7IM7
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Re: New Koa and Spruce

Post by iim7V7IM7 » Wed Jul 23, 2014 3:25 am

Infinitely more entertaining (and higher in fiber to boot!)

Kudos
Peter Oberg wrote:Not as entertaining as the double top thread, or the Ruck for sale thread, but here's the latest.

The neck ready for the fingerboard. Two pins locate the board, one at the first fret and another at the 13th, just to the right of the spline.
Image

Marking the board where it meets the sound hole edge. Going to do a 20th fret.
Image

Template and finished end of the board. I'll fill the bass side of the 20th fret later.
Image

Showing the neck and upper bout in plane. Neck angle is forward.
Image

A little hard to see here, but the fingerboard is a straight line right to the sound hole.
Image

Last check on the fingerboard alignment relative to the center line.
Image

The clamping set up. I love wooden screw clamps.
Image

Clamping above the 12th fret. The middle larger C clamp has an angled caul that fits to the foot.
Image
2015 - John Buscarino, 650 mm, Carpathian Spruce/Honduran Rosewood
2014 - Peter Oberg, 640 mm, Western Red Cedar/Black Cherry

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Paul Janssen
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Re: New Koa and Spruce

Post by Paul Janssen » Wed Jul 23, 2014 4:02 am

Hi Peter,

It's looking really nice. It's also amazing how similar the KOA looks to Australian Blackwood.

Regards,
Paul

riffmeister
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Re: New Koa and Spruce

Post by riffmeister » Wed Jul 23, 2014 2:12 pm

The guitar looks even more beautiful as the assembly continues!

Charles Simons

Re: New Koa and Spruce

Post by Charles Simons » Wed Jul 23, 2014 3:43 pm

Hate to come across as the clueless newbie that I am, but is a forward neck angle the norm? I've been building steel string and electrics and 1.5 degrees back is what I'm usually looking for

Fantastic workmanship!

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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Wed Jul 23, 2014 4:16 pm

Paul Janssen wrote:Hi Peter,

It's looking really nice. It's also amazing how similar the KOA looks to Australian Blackwood.

Regards,
Paul
Thanks. Koa and Australian Blackwood look alike because they are both species of the Acacia family. Very similar properties.

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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Wed Jul 23, 2014 4:17 pm

riffmeister wrote:The guitar looks even more beautiful as the assembly continues!
Thank you kind sir!

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Peter Oberg
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Re: New Koa and Spruce

Post by Peter Oberg » Wed Jul 23, 2014 4:38 pm

Charles Simons wrote:Hate to come across as the clueless newbie that I am, but is a forward neck angle the norm? I've been building steel string and electrics and 1.5 degrees back is what I'm usually looking for

Fantastic workmanship!
Thank you for the kind comment. The neck angle is dependent on the geometry of the system, i.e. how much dome is in the soundboard, what is the desired string height off of the top (bridge design), and what is the target action height and fingerboard thickness. I need a little forward neck angle to achieve this. Flat top steel string guitars will be different, and other classical makers will no doubt use a different neck angle than what I use.

Classicalmark

Re: New Koa and Spruce

Post by Classicalmark » Fri Jul 25, 2014 1:25 am

That is a very beautiful guitar. I particularly like the rosette and head stock. The headstock ornamentation reminds me of Simplicio guitars that I have seen (never played though). Thanks for sharing.

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