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partial cutaway
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Author:  Andy Zimmerman [ Fri Nov 29, 2013 1:15 pm ]
Post subject:  partial cutaway

Hi All
I have been asked to include a partial cutaway on my next commission and I have never made one. Any help would be appreciated.
I have included a pict of an example.
Thanks
Andy
Image

Author:  Alan Carruth [ Fri Nov 29, 2013 1:34 pm ]
Post subject:  Re: partial cutaway

There's a tutorial in a recent 'American Lutherie' on how to do that. He starts with a block and carves it to shape. I prefer to bend a piece of wood a little thinner than the usual side thickness, and put in liners on the top and side to support it. My sequence is to bend the piece, make the cut to fit pretty closely, put in the liners, and chalk fit from there to get it just right. Burton LeGeyt, the maker Ipicked uyp the idea from, makes the cut and bends the piece to fit. To each his own.

The main issue with this is getting the purfling in around it. So far I have not been able to think of any way to do it other than hand cutting it in, which calls for some serious tool chops. I suppose you could jig up for it if you had really tight control over the side and cutaway shape, but that's beyond me.

I like to make a 'recurve bevel'. I bend the piece for the cutaway into an S-curve, so that the outer end round off and ties in with the binding. It looks a little more 'finished' to me. There should be some pics of one of those guitars in the article about Ken Bonfield in the January 'Acoustic Guitar'. I haven't seen it yet, but he's using one in the tutorial on their web site.

Author:  Andy Zimmerman [ Fri Nov 29, 2013 3:45 pm ]
Post subject:  Re: partial cutaway

Thanks Alan
I am looking through my American Lutherie collection and I cannot find it. Do you know which issue it is

Author:  Burton LeGeyt [ Fri Nov 29, 2013 8:00 pm ]
Post subject:  Re: partial cutaway

Andy,

I've done quite a few of these at this point-

The neck block has the support for the cut integral:

Attachment:
clm-tamco-neckblk-close.jpg


Then the guitar is built as normal around that. When cutting purfling channels you cut the channel for the puffs in the top and connect them before opening up the cutaway. The purling in that area has a small strip glued to the inside of the same wood as what the cutaway overlay will be. That way when you sand just up to the purling you have a little cheating room.

Attachment:
CLM-TAMCO-body-with-channel.jpg


Attachment:
CLM-TAMCO-bevel-purfling-cl.jpg


When that is all in you open up the cutaway area and sand VERY carefully all in the exact same plane, slowly sneaking up on the top purfling. This was nerve racking at first and now is not bad at all. When that is done and smooth you bend the overlay to fit and trim it to just slightly oversize. Then I tape and rope it in place.

Attachment:
CLM-TAMCO-cutaway-prep.jpg


I think there is this process also shown in my documented build in the tutorials section. I didn't make the support integral then. I feel that is a big improvement and would recommend doing it that way.

Hope that helps-

Author:  GregG [ Fri Nov 29, 2013 8:17 pm ]
Post subject:  Re: partial cutaway

Hi Andy,

Looks like you have what you need here....it is pretty easy really, happy to help if you feel you need it.

Greg

Author:  Shaw [ Fri Nov 29, 2013 8:17 pm ]
Post subject:  Re: partial cutaway

Nice pointers Burton. ...Mike

Author:  Andy Zimmerman [ Fri Nov 29, 2013 11:18 pm ]
Post subject:  Re: partial cutaway

thanks for all the info and photos!!!!

Author:  Joel M [ Sat Nov 30, 2013 2:30 am ]
Post subject:  Re: partial cutaway

Hey Andy

I have done a bunch of these now as well.
Attachment:
IMG_1186.jpg

Attachment:
IMG_1019.jpg


I have done them many ways and am constantly changing the process.

Basically is starts with supports on the rims and top.
Attachment:
IMG_1338.jpg

Then a template for routing the top purfling lines.
Attachment:
IMG_1390.jpg


This creates a guide for the scoop to begin. I do mine with a combo of power and hand tools, and always slowly sneak up on the line. It gets a bit tricky as you have to maintain the same angle all the way across while not overshooting the top purling.
Attachment:
IMG_1394.jpg


Alan is right about the purfling carrying through on the sides being tough. It takes a lot of patience for me and some finicky handwork. I haven't seen them done like this before,
Attachment:
IMG_1461.jpg


Burtons work is awesome!!!

Joel.

Author:  nyazzip [ Sat Nov 30, 2013 2:54 am ]
Post subject:  Re: partial cutaway

all very cool stuff; never heard of a "partial cutaway" until tonight. i like the concept. just wondering what the structural risks are if not executed correctly-what form will the results of failure manifest themselves as, in your guys' estimation...? just to throw a guess out there i'd say maybe a body corkscrew twist in the direction of the cutaway, resulting in high action on the low E, and strings touching the fretboard on the high E?

Author:  Clay S. [ Sat Nov 30, 2013 9:54 am ]
Post subject:  Re: partial cutaway

Thank's Y'all!
For sharing how you do partial cutaways. For those of us who have never done one that is a lot of good information. Seeing what problems we might run into, and how people have solved them can help us avoid a lot of mistakes and wasted effort.

Author:  Burton LeGeyt [ Sat Nov 30, 2013 10:44 am ]
Post subject:  Re: partial cutaway

Joel, nice work! Getting the side purling in there is very tricky. No one has insisted lately that I include it and that is fine with me. I've just about removed side purfs from all my builds lately.

You all should find a way to check out Alan's recurve version, it is wonderful. This thread on the AGF shows it completed (and his insane rosette!):
http://www.acousticguitarforum.com/foru ... ht=carruth

Nyazzip, I have had these out in the world for years at this point and they have been doing fine. I wondered at first what the issues would be but have not found it to be any less stable than my non-cutaway guitars. I do feel better locking all the support into the neck block (and my neck blocks are already bigger then most) but even the earlier versions have been fine. I don't worry about it anymore.

I will say that the shape matters in how it feels to reach up in that area. I feel it is important that the cutaway dives straight in at first by the neck (running more or less parallel to the centerline, or at least FB edge) so it doesn't angle away from the heel right away. It is a subtle difference, but one that I think matters in how useful it is.

Author:  Pat Foster [ Sat Nov 30, 2013 11:13 am ]
Post subject:  Re: partial cutaway

Good to see your post, Andy!

I did this one last year, pretty much following Allan Carruth and Burton LeGeyt.

Attachment:
DSC_0037.jpg


It's documented at the Luthier Community.

http://www.luthiercom.org/phpBB3/viewtopic.php?f=92&t=3192&start=50

Registration is required, but it's painless.

What I'll do differently next time is cant the "bottom" of the bevel closer to the neck.

Pat

Author:  Alan Carruth [ Sat Nov 30, 2013 7:57 pm ]
Post subject:  Re: partial cutaway

Thanks for posting the link, Burton. That's the simple rosette, although it came out nicely on that one. I really need to set up a 'Photobucket' account or something so I can post stuff on this forum.

A quick scan of my AL's didn't find the article either: maybe it was in 'Guitarmaker'?

Author:  meddlingfool [ Sat Nov 30, 2013 8:12 pm ]
Post subject:  Re: partial cutaway

Just out of curiosity, what benefit does this have over a standard cutaway?

Author:  Shaw [ Sun Dec 01, 2013 2:07 am ]
Post subject:  Re: partial cutaway

I don't know if there is a benefit but it does look cool compared to the basic cutaways. I know some people prefer non cutaways swearing they have a fuller sound compared to cutaways. I don't really hear any difference myself. So maybe this is a compromise between a non cutaway and a cutaway. Mike

Author:  nyazzip [ Sun Dec 01, 2013 3:10 am ]
Post subject:  Re: partial cutaway

Quote:
Just out of curiosity, what benefit does this have over a standard cutaway?


yep like shaw said, less loss of body volume should equal better sound...it looks like it is probably physically stronger overall than a full cutaway, as well

Author:  Burton LeGeyt [ Sun Dec 01, 2013 8:32 am ]
Post subject:  Re: partial cutaway

Yeah, I think the biggest benefit is the uniqueness-

Personally I like that the back is uninterrupted, aesthetically that does it for me.

It is pleasant the way your hand glides up the bevel when playing lead runs but depending on how you play (and how the bevel is shaped) this could be pretty specific to your personal playing style.

For chords above the body join a regular cutaway is preferable as your hand needs to wrap around more than the bevel allows for (easily).

As to the body volume I agree that technically it seems like it should improve the sound to lose less air but practically I have a hard enough time hearing the difference between a regular guitar and a cutaway guitar to then make a distinction between different cut styles as well. I'm not saying that that sensitivity won't come about after I have built more, but now I don't notice it that much.

Author:  Alan Carruth [ Sun Dec 01, 2013 12:40 pm ]
Post subject:  Re: partial cutaway

Given the limitations of my hearing, I sure don't notice the difference. However, one of my customers, who has 'Golden Ears' and now runs his own studio, claims that cutaway guitars are easier to record, so there must be some difference. I suspect the cutaway makes them less 'peaky', probably due to the asymmetry, but can't swear to it. I am sure that the air volume in the upper bout, and the way it's distributed, makes a difference in the sound, so it seems to me that preserving it should matter: if I were doing a double cutaway, I'd certainly use a bevel.

I think the bevel cutaway is probably more useful to players who use Classical technique, and reach up over the top anyway. In that case it adds a lot to the high fret accessibility. If you normally play standing, or play with your palm down along the side of the neck, it won't help as much.

I just think it's sexy, particularly with the recurve....

Author:  cphanna [ Sun Dec 01, 2013 1:14 pm ]
Post subject:  Re: partial cutaway

The "WOW" factor is undeniable. You guys just amaze me with the level of craftsmanship that so many of you possess.
I am confused about how the cut is actually made. Please explain.
Many thanks and congrats to all.
Patrick

Author:  Joel M [ Sun Dec 01, 2013 1:22 pm ]
Post subject:  Re: partial cutaway

OH man Alans work is so amazing! I got to see one of his recurves in person at healdsburg and it blew me a way. Thanks for taking a bit of time Alan and explaning to me your process aswell!

As for stability I agree that it posses no issues, and is stronger than a regular cutaway in that it is more firmly anchored to the body. In use I find it better than no cutaway but not a useful as a regular one. ;) I also like the way a regular guitar feels in my lap better than a cutaway. So you get a bit of both worlds with the scoop. I havent been able to pick up on any sound repercussions.

I first saw it done by Nick Benjamin a good while back. Although im sure it had been done before him.

Author:  aqualibguitars [ Sun Dec 15, 2013 2:27 pm ]
Post subject:  Re: partial cutaway

Thanks friends
it was so helpful
will use on my next guitar

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