1. #1

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    Hi guys, new to this forum. I'm a bass guitar luthier and want to build my first archtop guitar. I've had the Benedetto book and videos for years now and it's time to finally build one.

    I'm going to base my build on the 15" Benedetto Bambino. My questions are related to what I couldn't find in the book or videos lol. I'd like to install two humbuckers with two knobs and switch directly into the body like most semi-acoustics do. I've been trawling the net to figure out how to brace the carved top for supporting the pickups and finally fell on some photos from the Bambino page. Refer to photos below...

    My questions; I can see from the way Benedetto braces his Bambinos that it looks like the 5 transverse braces seem to support a particular area. The 4 closest to neck appear to be placed about 6mm from the side of each pickups. The 5th brace I can't figure out, it seems too close to the tail end to be under the bridge for extra support. Does anyone know where that 5th is placed and why?

    Also are the pickup rings only screwed directly into the top or would the 4 first transverse braces be there for actually having a spot where to screw in the rings?

    Lastly I'd like my jack to be on the side of the body with the three holes for pots near the bottom f-hole. How much wood should I glue at the hole locations to strengthen the top and side? (if at all) i.e. wood thickness, grain direction etc..


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  3. #2

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    Also notice there appears to be a block from the brace under the bridge to the back, in the last photo. This is a semi-hollow guitar, functionally.

    Those braces are massive mainly, I suspect, to prevent feedback at stage volume (or they were carved down significantly before the top went on). In an archtop guitar, bracing is basically the same with vs. without pickups- the braces are positioned slightly differently to make room, but they are no heavier. An arched top supports string tension differently from a flat top. The Benedetto book demonstrated X vs. "parallel" bracing, IIRC, different from the ladder bracing here.

  4. #3

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    Here you go.
    This is the underside of a Gibson carved top for an L-5CES or Byrdland. The placement of the small crossbraces between the parallel braces can be moved, depending onto which model it is being installed. Minor crack repair w/cleats done by Gibson and then it went into inventory as a replacement top.
    Attached Images Attached Images Archtop Pickup Rout Q's-l-5cesbyrd-back658-lo_zpseg21wo5a-jpg 
    Last edited by Hammertone; 05-24-2020 at 09:53 PM.

  5. #4

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    Nice, thanks, what are the white spots on the pot holes? Is that extra wood to make out for thickness and strength?

  6. #5

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    Quote Originally Posted by Phil Mailloux
    Nice, thanks, what are the white spots on the pot holes? Is that extra wood to make out for thickness and strength?
    Carved-top instrument builders often use small pieces of cloth (typically muslin) glued in to prevent any tendency to splitting - one typically see this around the holes for potentiomenters, and above/below or even completely surrounding the f-holes on instruments that do not have bound soundholes.