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| Help with cutaway and pitfalls http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=1583 |
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| Author: | LanceK [ Tue Apr 05, 2005 1:56 am ] |
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ok - I'm working on my first Cutaway, its not going to be squared off at the neck joint but rather, the body will conform to the heal of the neck - Here is a picture of a Mark Blanchard guitar that shows what Id like to do. 
Mark does amazing work! - What I'm worried about is making the neck block, what do I need to think about in advance? What are the pitfalls? Thanks -- Lance |
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| Author: | Bobc [ Tue Apr 05, 2005 2:45 am ] |
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Seems to me that the neck block has to be shaped to follow the neck heel shape minus the side thickness. It shouldn't be too difficult to bend the side to conform. I like to draw this sort of thing full size. That's were the pitfalls show up. |
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| Author: | Michael Dale Payne [ Tue Apr 05, 2005 2:57 am ] |
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Sure you don't want to do a full width heel on this one  ..but really it would eliminate the the need to bend the cutaway side with the grain. What would scare me is the cutaway side splitting while bending the heel conture.
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| Author: | crazymanmichael [ Tue Apr 05, 2005 3:32 am ] |
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an elegant solution to an often awkward area. have you approached him for advice on making the bend/contour? first impression is that a using a set of suitable contoured nesting blocks which support the cutaway curve as well as impart the contour could ameliorate the risk of a split. before i did it with a high priced set i'd try it with a few cheap sides. what about the laminated ones offered on site if still available. michael mcclain |
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| Author: | Josh H [ Tue Apr 05, 2005 4:32 am ] |
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Lance This is something you also see on the guitars of the de Jonge family. You can see some more pictures of this type of cutaway on the de Jonge Guitar company site www.dejongeguitars.com . This is going back almost 2 years but I remember a few of us who were taking the course discussing this method with Joshia de Jonge. I was also able to examine some guitars in progress that were getting this type of cutaway. From what I can tell you need to start by carving the same profile you will use in the heal into your head block minus the thickness of the sides (like Bob send). Next you bend the sides and glue them up. The tricky part is gluing the sides to the contoured block. I remember Joshia saying that you need (or maybe that should be might need) to fracture the side a bit to get it to glue to the block. This probably depends on how much to contour the heal. You glue any cracks you make up with CA when you are done. She said it is pretty easy (yea, for an expert like her I’m sure) to hide the cracks with dark woods but much harder with lighter woods like maple. Then I guess you need to carve the heal to match the block. I have never done this before but am going to give it a try sometime. This is just how I think it is possible supposed to be done. Hope that is a little helpful. Take a look at the concert classicals page on Joshia's site to see an example of one of her guitars with this feature. joshiadejonge.com Josh |
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| Author: | LanceK [ Tue Apr 05, 2005 4:43 am ] |
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Thanks Josh, thats pretty much how I figured I had to do it. After bending this ziricote side, I did some flex testing and its very flexible, so I think it will conform to the heel quite well, with out to much convincing. |
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| Author: | LanceK [ Tue Apr 05, 2005 4:52 am ] |
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Joshia's cutaway - again - amazing work! 
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| Author: | Brock Poling [ Tue Apr 05, 2005 4:54 am ] |
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I would reinforce the inside of that just below the neck block pretty good. That looks like it is just begging to split out. Especially on a wood that is known to split anyway like ziricote. |
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| Author: | Brock Poling [ Tue Apr 05, 2005 4:56 am ] |
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Another thought.... When I have done these cutaways in the past there has been a notch in the form to accept the side as it hangs off the end of the front block (ala benedetto). If you use that approach your slot in your form is going to have to be a match for your front block and side. That seems to add more complexity to this presuming that is the approach you take to glue up. I know Paul Woolson does this. Maybe he would care to share his approach. (Not to put you on the spot or anything Paul...  ) |
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| Author: | Wade Sylvester [ Tue Apr 05, 2005 4:59 am ] |
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Lance, It’s a lot simpler than it looks. Put it on paper first, full scale, like Bob said. I also made up a mock up block with the contour and clamped it to a table with a profile of the side drawn on paper. I used a hot pipe to make the bend and keep checking it against the block and penciled outline. When it was close enough, I clamped it in place and left it to dry. I didn’t have trouble with cracking. I don’t think it is putting any more stress on the wood than any other bend. But, then again, I wasn’t bending Ziricote either. The only other thing I should mention is to make sure you are bending in the right direction or you will end up with a lefty. (Don’t ask how I know this) 
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| Author: | LanceK [ Tue Apr 05, 2005 5:02 am ] |
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Thanks Wade - looks great BTW |
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| Author: | Wade Sylvester [ Tue Apr 05, 2005 5:06 am ] |
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Lance, Also, I used epoxy to glue the side to the block BTW. It fills in any voids that may occur. Wade |
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| Author: | LanceK [ Tue Apr 05, 2005 5:09 am ] |
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clever :) and makes it nice and solid! |
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| Author: | Michael Dale Payne [ Tue Apr 05, 2005 6:04 am ] |
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[QUOTE=LanceK] Joshia's cutaway - again - amazing work! [/QUOTE]
Man that looks good, But I would say I think it needs binding between the heel and the body. To me the side just kinda end .JMO |
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| Author: | EricKeller [ Tue Apr 05, 2005 9:12 am ] |
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Those guitars are really inspiring. The number of people out there doing quality work is just amazing. |
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| Author: | Rick Davis [ Tue Apr 05, 2005 1:42 pm ] |
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One of my early projects was based on an 1840's Martin, shown in Washburn and Johnston's Martin book, with what amounts to a double, tapered cutaway. Here's one shot of the joint -- 
I bent the twist by hand after the other bends were done in a Fox-style bender. It's no more likely to split than any other part. (That may not apply to Josiah de Jonge's complex shape.) The headblock was shaped on the bandsaw and drum sander to get both the taper and recurves. The mold is complex, allowing for different neck widths while supporting the taper. Sides are attached with epoxy. Clamping was a nightmare, requiring clamping the entire mold to a rigid form that also located the headblock. The neck is set with a mortise-and-tenon. One thing that no one has mentioned is that the sides have to be wider at the head due to the twist. The edge that contacts the back of the guitar will have a slight flare. Have fun! It's good hand-bending practice. |
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| Author: | PaulB [ Tue Apr 05, 2005 2:17 pm ] |
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Thats realy very inspiring work, far beond anything can can do at the moment. I'll still add my opinion though 
Instead of cracking the heelblock side, could you just wet it with some water instead, and try to induce some cupping of the side? Just a thought. |
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| Author: | LanceK [ Tue Apr 05, 2005 10:21 pm ] |
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Wade, I just noticed you used a matching piece of your back for the heel cap, I see the grain lines match - VERY nice and good thinking ahead.... |
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| Author: | John How [ Wed Apr 13, 2005 1:45 am ] |
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Hi Lance, I am in the process of making one of these as well. Just glued the headblock in last night. When I bent the sides I made a form that conformed to this geometry so the compound curve was formed in the side when I bent it. Kind of a pain to make the cawl fit exactly right but it worked. The other thing is making the headblock to fit this compound curve, I went as far as I could on a drum sander and then went a little further with the drum sander holding the headblock freehand off the table. Then it was sandpaper, files and a fingerplane till it fit right. I went too far on the first attempt because I didn't check the fit often enough on the back side so I had to start over. The other great pain is clamping the thing in place. It's done now and will unclamp tonight and see how it came out. |
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| Author: | russ [ Wed Apr 13, 2005 2:14 am ] |
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Lance, Lots of good ideas here on how to do this...if your side is thin enough in the headblock area, I would think it will conform fairly well without too much drama. Just thinking out loud...It should work to form the heel (minus the side depth), cover the curve with a sheet of Saran Wrap© (or other non-stick substance)and then use some "Friendly Plastic" (available from StewMac) to make an outside caul you can use when clamping the side to the block. That should distribute the clamping load enough to lessen the chances of cracking the side. |
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| Author: | LanceK [ Wed Apr 13, 2005 2:23 am ] |
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Thanks Guys! |
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| Author: | Pwoolson [ Wed Apr 13, 2005 3:15 am ] |
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Lance, like Brock said I do compound cutaways. Sorry, I've got NO pics of one completed. Is your heal a straight taper or classical curve like Mark B's? One of the easiest ways I found to rough out the curved heal is on the table saw. If you do this, I'd bolt the neck block in with a shim the width of the side. Then do it all in one step. If it's just tapered, all you need to do it cut it same taper as the neck less the thickness of the side. That's the easy part. Bending the wood isn't too bad, you'll want to leave it deep as the compound part will take about 1/16" from the back (the side won't bend along its width very well). You have to be a little more careful when blocking it all up as the block will want to ride up the, now created, ramp of the equation. Not a big deal, just something to keep you eye out for. Lining the guitar will suck, no two ways about it. You'll be asking the lining to bend in two different directions without breaking. Binding the guitar will SUCK! On the top your chanel will be deep as the bearing is riding deeper in the cutaway than the chanel will be. Just the opposite on the back. I've recently found a fix for this. I route the whole guitar except the compound part of the cutaway. Then I adjust the body so the compound area is perpendicular to the table instead of the blocks. Quick fix and it worked great. you still might have a bit of hand work to meet the chanels up. Do your neck last so you can make it fit the body. Cause you AIN"T changing the body at this Point. That's about it. It's straight forward but challenging. |
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