Modifications for Cut-away Build

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PSmill
Posts: 111
Joined: Sun Sep 09, 2018 12:23 pm
Location: British Columbia, Canada

Modifications for Cut-away Build

Post by PSmill »

Hi, Just starting my first cutaway, and will be mostly using the plan/mold etc. from my previous OM build. I spoke with JH briefly about the required modifications and he gave me the goods, but I'll have more questions so I'll throw them out, and would appreciate any photos too.

Neck Block Modification - Here is a pic of a mocked up neck block , I have not yet bent the sides or cut the real block, or made the cut in the mold to receive the cutaway side. Just want to be sure I have this correct and if anyone has a photo to share of their that would be great. It is the regular neck block (2 3/4 wide by 1 1/4 deep), but with the treble side marked to be cut following the line of the fretboard minus the thickness of the side (so the finished side will flush with the fretboard.). To confirm....the line follows the angle of the fretboard shape? ie. it is not parallel to the centre line. And then the kerf in the mold to receive the side is aligned with that.

Side profile - I have added the3/8 hump from 1.5" to 10" to the treble side profile, as per Johns video

Bracing - Just requires the upper transverse to be shortened to fit the body shape. I was reading this brace can be beefed up a bit (I'm using the stewmac plan so I think it's a more traditional dimension). Does anyone suggested adding a bit of height to the brace to stiffer it or otherwise?

Thanks for any suggestions!
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Stray Feathers
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Joined: Sun Sep 08, 2013 11:39 pm
Location: Ladysmith, BC

Re: Modifications for Cut-away Build

Post by Stray Feathers »

I've not done a cutaway, so can't comment helpfully. But, in looking for images of L'arrivée - style bracing, I came across two cutaways. One is by one of his protegés, Grit Laskin, which shows the UT brace set at an angle to go across from one side to the X-brace on the opposite side. It's from an American Lutherie teaser article online. The other (which is either a lefty or a reversed image) shows a brace partway across. I don't know the source of that image. So, ignore the lower bouts, but maybe you can see something helpful in the uppers. Sorry they are low-res - they are web files. Keep us posted on your project! Bruce W.

Edit - just found a third image (at top) which may help you.
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jread
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Re: Modifications for Cut-away Build

Post by jread »

Here are my recent builds. I'm still learning but here's my go. This was my 1st two attempts at a cutaway. I didn't modify the bracing from a non-cutaway but hey, I like that idea and the above post.

I spent many hours going over the same questions you have. I won't attempt to describe it all as these aren't perfect by far. But they play well. You can see my block has radius in it that follows the curve of the body. I found a few reference builds here I tried to emulate.

I spent a lot of time discovering exactly how wide the fretboard would be at the body joint and trimmed it just that wide being super careful w/ the centers. Pay attn to the final target thickness of your sides when making the block too. My 1st one was too wide so I had to unglue the block, trim it and go again. HHG is just great stuff.

Feel free to DM me if this was useful and you'd like more.
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tippie53
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Re: Modifications for Cut-away Build

Post by tippie53 »

your neck block analogy is spot on
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
PSmill
Posts: 111
Joined: Sun Sep 09, 2018 12:23 pm
Location: British Columbia, Canada

Re: Modifications for Cut-away Build

Post by PSmill »

Thank you for the advice and photos! My take aways are....1 - use a deeper neck block, maybe 2" deep (from neck end towards sound hole) rather than the standard 1.25", 2 - angle or curve the cutaway side of the block to receive the side, 3 - cut the block to width so the side is flush with the fretboard, and 4 - maybe adjust the upper brace. Thanks! P
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