A new Blackdog Korina DC.

Discussion in 'Guitar Building' started by Blackdog, Apr 18, 2013.

  1. Blackdog

    Blackdog Member

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    A lot has happened during this past few days.

    Binding time: after trying to bend some cocobolo binding to fit the tight curve of the upper horn without much success I opted to simplify the approach and go for a tortoise plastic binding instead. A lot easier to work with and gives me pretty much the same look I was after.
    Today I would normally carve the top before cutting the binding channlel, for for this build the channel had been cut 5 years ago. I needed to sort the binding before attempting the work on the carve to minimize the risk of accidentally ruining the edges.

    First step with plastic binding is to pre-form it with the heat gun to reduce the spring-back effect when gluing. For the glue I simply used binding chips dissolved in acetone to a slightly thick density.
    [​IMG][​IMG]

    Left to dry/evaporate the acetone overnight.
    [​IMG][​IMG]

    With a razor blade, shaved the binding down to the top level, and the same on the sides. I found that this tortoise plastic behaves in a strange way: some small areas remained soft and spongy for much longer. Most of the binding was hard the morning after, but there were a few spots that were still soft two full days after. Eventually everything hardened, but it was an unexpected behaviour.
    [​IMG]
     
  2. Blackdog

    Blackdog Member

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    The very next thing I wanted to do was to route the neck pocket.
    I do it in two steps, first I create a fresh template for the neck, and then I route the pocket. I still have not come around to make a proper neck pocket jig….
    [​IMG][​IMG][​IMG]

    This method still works well for me and generates a very tight pocket.
    Setting up for routing the pocket. The template was set over the top at a 4.3 degrees angle.
    [​IMG]

    Going slowly, with a set of different length router bits I got the pocket routed.
    [​IMG]

    Got a very nice and tight fit.
    [​IMG]

    Now that the neck could be inserted in place I market the exposed part of the heel and adjusted it accordingly visually follow the asymmetrical nature of the neck insertion point properly.
    [​IMG]
     
  3. Blackdog

    Blackdog Member

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    Now the P90 pickup cavities.
    I routed the cavities at the same angle of the neck, like on LPs.
    [​IMG]

    Here I made a mistake. The idea was to make the two step cavities as in vintage LPs, but I mis-read the plan and routed the "big" cavity to the depth of the "T-shaped" cavity. So I decided to leave it like that and do the bridge cavity in a similar way.
    [​IMG][​IMG]

    With the neck inserted in place, I have always found that the actual centerline departs a little from the theoretical center. So before continuing with the bridge pickup cavity it is necessary to find the real centerline.
    [​IMG][​IMG][​IMG]

    Same drill with the template following the neck angle for the bridge cavity. Now centered with the actual centerline. Both cavities are routed to the same depth relative to the theoretical fretboard plane.
    [​IMG]
     
  4. Blackdog

    Blackdog Member

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    Time to pay a little attention to the back.
    This body is a bit on the thin side, so for the back roundover I opted for a 3/16" radius istead of my usual 1/4".
    [​IMG][​IMG]

    And now the belly cut. Marked the limit line on the back of the body using a template.
    [​IMG]

    And started removing wood with the rasps.
    [​IMG][​IMG]

    After some sanding down to 120, the belly cut is done. Here it can also be seen how the asymmetrical heel follows the body at the insertion point.
    [​IMG]
     
  5. Blackdog

    Blackdog Member

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    And finally ! Top carving time !!!!!
    First attack with the orbital sander and 80grit paper to smooth down the steps as much as possible.
    [​IMG]

    Then cabinet scrapers, and the good old 60/80 grit sandpaper on the cork block.
    [​IMG]

    For the waists it is mostly scrapers and sanding, the horns are shaped with a fine rasp first and then scraped/sanded to final shape. Sorry, not many pictures of this. Once started I sort of got carried away...
    The preliminary carving is now done. Over the next few days it will be refined and adjusted along several sessions.
    [​IMG][​IMG][​IMG][​IMG]

    I'm pretty happy with the carve resulting from the templates. It is softer than the older one, but it looks very organic and flows really well.

    This is already becoming a cute little doublecut guitar.
    [​IMG]

    And that's all for the time being. It too five posts and 32 pictures to tell you, so I'd say these have been a few pretty productive days. :)
     
    Last edited: Jun 17, 2013
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  6. SimonB15

    SimonB15 Active Member

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    Am loving this build, by the way :D thanks for sharing!
     
  7. Blackdog

    Blackdog Member

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    Thank you for the kind words ! And welcome !
     
  8. TKOjams

    TKOjams Well-Known Member

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    Love the contours!!!
    Another beauty, Man.
     
  9. Blackdog

    Blackdog Member

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    Not a lot of progress to report…

    I'm still undecided about which bridge to use.

    The guitar was originally thought for this fixed aluminium wraparound by ABM:
    [​IMG]

    It remains the simplest of all possible alternatives, but I am also trying to make this design a bit less PRS-ish. I've already decided to avoid the extreme scoop in the lower cutaway (which I have used in the past), and this fixed wraparound is a clear clone of the PRS bridge…

    The other candidates I have around are:
    [​IMG][​IMG][​IMG]

    The adjustable Tone-Pros wraparound (or the aluminium Pigtail equivalent), the adjustable ABM wraparound or I could go traditional Gibsony and use a separate ABR/STP setup.
    Still thinking… I do believe that a wraparound looks best, but opinions welcome !

    In the meantime I levelled, re-crowned and polished the frets to 320 grit. There's still work to do with the neck, so polishing the frets further would be useless at this stage.
    [​IMG][​IMG]
     
  10. WTM Guitars

    WTM Guitars New Member

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    Awesome as always!
     
  11. SG John

    SG John New Member

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    Great looking build. Aesthetically, I would go for one of the wrap-tail bridges. They seem to look best. And, they resonate quite nicely.

    The ABM does look very sharp.
     
  12. LC100

    LC100 New Member

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    Agreed. On a side note I think a Hannes bridge would look pretty nice on this shape. A little too late to consider it now but maybe on a future guitar.
     
  13. Blackdog

    Blackdog Member

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    Agreed, it will definitely be one of the wraparounds.

    I proceeded with the dishing of the top around the control holes.
    There are several ways to do this, CNC being the most convenient by far !:D

    I developed a new way of doing this and this build was again the test bed.

    I started with just the pilot holes.
    [​IMG]

    Next, using an 18mm diameter forstner centered on the holes, I generated a flat surface at the desired depth.
    [​IMG][​IMG]

    Then I made a template for use on a pin router, with round holes of 20mm (2 mm more than the forstner used on the top, the diameter of the pin).
    [​IMG]

    And no, I don't have a pin router. But I have this:
    [​IMG]

    A drill press for hand-drills. I also have a Metabo router that can be detached from the plunge base, and the mounting collar has the same standard diameter of the hand-drills.
    So it was a matter of making a base with the pin (yes, a proper diameter nail works fine) and center the router with it.
    [​IMG]

    And I have now a pin router perfectly adequate for these non-critical tasks.
    [​IMG][​IMG]

    And it's done.
    [​IMG]
    [​IMG]

    Next I will have to adjust the depth of the cavity for those controls that sit higher on the top.
     
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  14. rockdog

    rockdog New Member

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    Perfect as always :yesway:
     
  15. Blackdog

    Blackdog Member

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    Thanks RD ! I wouldn't say perfect, but certainly trying to make every process consistently repeatable.

    I finished with the control cavity. The two front control pots (volumes) sit at the same level, the third pot (tone) is a bit higher and the switch is at the highest point. This is fully consistent with the templates I used for the top carve.
    [​IMG][​IMG]

    The cavity needs to be selectively deepened. These are the templates I used.
    [​IMG]

    A first pass to deepen the complete cavity with the first template to get the thickness at the two volume pots at 4mm. Then the second template to deepen that part of the cavity to get the thickness at the tone control at 4mm. And finally the third template to create the seating for the toggle switch and the thickness at 4.5mm.
    Finally, drilled the holes for the controls: 3/8" for the pots and 1/2" for the toggle.
    [​IMG]

    Fit testing the controls in place:
    [​IMG]
    [​IMG]

    Now I only need to drill the jack hole on the side.
     
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  16. Adam

    Adam Well-Known Member

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    The cavity looks really great, good job!
     
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  17. Blackdog

    Blackdog Member

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    Some more progress to report on this build.

    I was not completely happy with the fit of the control cover that I made back in 2008, and besides that, I've been using magnets instead of screws to attach the covers lately.
    [​IMG]

    So I made a new cover template with a much better fit and cut a new cover out of the same korina the body was made of (amazing that I still have wood scraps from these old builds). Used the template to make the recesses for the magnets. I'm using round neodymium magnets, 1/4" diameter and 1/16" thick.
    Glued the magnets in place and filled the now unused screw holes. The cavity will be painted with black conductive paint, so the filled holes will be pretty much invisible.
    [​IMG][​IMG][​IMG][​IMG][​IMG]

    After re-checking the centerline with the neck in place once more and measuring 1000 times, I drilled the holes for the bridge studs. I finally decided in favor of the Tone-Pros adjustable wraparound. The korina body will probably benefit, tone-wise, from a slightly heavier bridge. In any case, if I ever want to go Alu, the Pigtail is a drop in replacement of the TonePros. Installed the ground wire and the post bushings were hammered in place.
    [​IMG]
    [​IMG]

    I also drilled the jack cavity. I drilled a 6mm pilot hole that goes into the control cavity and used a spade drill bit to make the jack cavity as deep as necessary, to allocate the jack with good margin, but not reaching the control cavity. It went well, but it's always a bit scary to work with a rather large spade bit in a hand drill. I've been wanting to switch to a better, more controlled, setup for a while. My drill press is not tall enough to have the body held vertical and use a forstner, so I ordered a 7/8" spotfacer with 3/16" guide. This should be far more controllable to work with.

    I also retouched the top carving quite a bit. I've been doing that for a few days now. I took some more "focal-light" pictures to appreciate the carving better, this helps me identify uneven areas that may still need attention.
    [​IMG][​IMG][​IMG][​IMG]

    Everything is now sanded down to 240, that should be enough until after the pore filling.
    I only need to drill the holes for the strap holder screws and then I can proceed to set the neck, polish the frets and fretboard and install the nut.

    Wood work is coming to an end on this one. Hopefully, I should be able to spray the lacquer before going on holiday in August...
     
    Last edited: Jul 2, 2013
  18. Knarbens

    Knarbens Well-Known Member

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    Really sexy!
     
  19. poro78

    poro78 Well-Known Member

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    Oh yeah!
     
  20. Blackdog

    Blackdog Member

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    Guys, thanks for your nice comments !
    It is indeed becoming a cute little guitar…

    Not a lot to add to the thread, but a little progress nonetheless.

    I drilled the holes for the strap pins. The front one includes a shallow flat recess for the pin to seat properly on the sharp radiused tip of the horn.
    [​IMG][​IMG]

    The frets and fretboard have been polished to 12000 grit (Micromesh), so it can be masked now for the finishing steps.
    [​IMG]

    The nut blank was shaped for a tight fit in the slot, I still need to glue it.
    [​IMG]

    So everything is ready for setting the neck, Friday is looking promising. I will use HHG, so I want to have a good couple of undisturbed hours for this.
     

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