The Jazz Guitar Chord Dictionary
Reply to Thread Bookmark Thread
Page 2 of 3 FirstFirst 123 LastLast
Posts 26 to 50 of 52
  1. #26
    Quote Originally Posted by rlrhett
    How the strings pull on a pinned bridge vs push on a floating bridge is not really a function of the bracing. It's not usually a controversial topic, and in my experience a relatively accepted function of physics; but what you do with that information is totally up to you. I've shared how I apply and think of it, but I've got no dog in this hunt. There are as many theories about how to build as there are luthiers.

    The point is to go out and experiment and build. You are the luthier, you don't need to do it the same as anyone. As I used to tell my students, the worst sounding guitar is the one that sits uncompleted in pieces in your garage. I can't wait to follow your build thread and see what you come up with!
    I did not realize that we were talking about the difference between the pin bridge and the floating bridge as a function of their bracing.

    "An arch top moves the top differently than a flat top. A flat top bridge twists the top, an arch top bridge pushes the top up and down."

    My confusion might have started here and the idea of the top moving up and down. I felt both methods drives the top up and down, my concept of twisting might be a little different, especially for the lower modes of excitation. I was really not too concerned with this though as it does not have much bearing on carving a top. Was more interested in your thoughts on Benedetto's top thickness and the resultant sound. I was thinking of getting the book but I looked through the index and most of the book is about things I already know from building flat tops. I do not want to follow a book and then get an instrument that is better suited as an electric instrument. I want to learn from others opinions and understand the thought processes they take to reach their designs rather than feeling my way in the dark for a number of builds. That would be fine if I was ten or more years younger or if I wanted to mainly build archtops. But lately I have been taking stock of what I want to do in life and how much time I have to do it. So I am hoping to learn from others in order to understand more on how to build one of these things without going down too many wrong roads.

    As it is, I think with the size of the guitar I want to build and the main purpose of it is for personal enjoyment rather than playing and competing with banjos I might build it differently. Maybe a little less height of the dome than a 16-17" guitar, maybe one size does not fit all. Possibly a 3" body although that brings in issues with having an arm bevel (oh goody, I am going to google archtops with bevels once I finish this post, although I bet I will see most being electrics).

    Not a lot of bevels on archtops it seems, mainly just a hint of a bevel. This one is interesting though.



    LHT Guitars -Fugue

  2.  

    The Jazz Guitar Chord Dictionary
     
  3. #27
    Hi Printer. That LHT "Fugue" is a real masterpiece of archtoppery. It was explained to me that placing the soundhole there really adds to the player's enjoyment

  4. #28
    Wouldn't the required thickness of the top plate, especially at the apex (where the bridge will set,) depend on the guage of the strings you will be using? Lots more tension if using heavy flat-wounds, compared to Hybrid Slinky .009 - .046. Regardless of choice of bracing type, the strength of that bracing would also need to be considered, wouldn't it?

  5. #29
    Quote Originally Posted by ArchieHollow
    Wouldn't the required thickness of the top plate, especially at the apex (where the bridge will set,) depend on the guage of the strings you will be using? Lots more tension if using heavy flat-wounds, compared to Hybrid Slinky .009 - .046. Regardless of choice of bracing type, the strength of that bracing would also need to be considered, wouldn't it?
    The static downforce on the top of a floating bridge instrument can be easily calculated - its high school trigonometry. RM Mottola has provided a very handy little wizard that does it directly

    Calculating Downforce on the Bridge (liutaiomottola.com)


    here is a hollow bodied arched top electric guitar, strung with 0.012 to 0.054 gauge strings (165 pounds of tension), the break over angle at the bridge is 13 degrees.

    Pre-build questions for a 15" acoustic bundle of joy.-img_4548-3-jpg

    Mottola's wizard puts the down force at 37 pounds. The significant thing here is that the force is perpendicular to the top, there is no rotational component as in a fixed (pinned or tied) bridge. Rlrhett has mentioned how he likes to judge the amount of deflection on the top, I have heard mandolin makers discuss the same thing.

  6. #30
    Quote Originally Posted by Freeman Keller
    The static downforce on the top of a floating bridge instrument can be easily calculated - its high school trigonometry. RM Mottola has provided a very handy little wizard that does it directly

    Calculating Downforce on the Bridge (liutaiomottola.com)


    here is a hollow bodied arched top electric guitar, strung with 0.012 to 0.054 gauge strings (165 pounds of tension), the break over angle at the bridge is 13 degrees.

    Pre-build questions for a 15" acoustic bundle of joy.-img_4548-3-jpg

    Mottola's wizard puts the down force at 37 pounds. The significant thing here is that the force is perpendicular to the top, there is no rotational component as in a fixed (pinned or tied) bridge. Rlrhett has mentioned how he likes to judge the amount of deflection on the top, I have heard mandolin makers discuss the same thing.
    Thanks Freeman and "RL". Sharing your tech understanding with us is both helpful and educational.

  7. #31
    And Printer:
    Remember Ken Parker Archtoppery. His tutorials explain and demonstrate the details of building your instrument. He describes why he chooses to carve his tops as thin as possible without compromising structural stability; and bracing in such a way so it supports the top under downforce at the apex while still allowing the top to flex sufficiently.
    The TOTNES SCHOOL of GUITAR MAKING has online tutorials that are also very helpful. These are just a couple examples out of many.
    I studied specific parts of these over and over before I even acquired my first tonewood.
    Enjoy the "journey."

  8. #32
    "An arch top moves the top differently than a flat top. A flat top bridge twists the top, an arch top bridge pushes the top up and down."
    QUESTION:
    Doesn't it make sense that a fixed bridge on a flattop acoustic would transfer the vibes in a "twist," since longtidudinal tension pulls clockwise (on a right-hand instrument) because the low E has more tension than the high E? Whereas, on an archtop with a floating bridge, longitudinal tension goes to the tailpiece attached to the tail stock; so, at the bridge there is only downward pressure, that would transfer vibes conically?

  9. #33
    Quote Originally Posted by ArchieHollow
    And Printer:
    Remember Ken Parker Archtoppery. His tutorials explain and demonstrate the details of building your instrument. He describes why he chooses to carve his tops as thin as possible without compromising structural stability; and bracing in such a way so it supports the top under downforce at the apex while still allowing the top to flex sufficiently.
    The TOTNES SCHOOL of GUITAR MAKING has online tutorials that are also very helpful. These are just a couple examples out of many.
    I studied specific parts of these over and over before I even acquired my first tonewood.
    Enjoy the "journey."

    I couldn't find the Totnes tutorials.

  10. #34
    Here's a pic of website
    Attached Images Attached Images Pre-build questions for a 15" acoustic bundle of joy.-screenshot_20230321-1445232-png 

  11. #35
    Quote Originally Posted by ArchieHollow
    Here's a pic of website
    Home / Introduction - Totnes School of Guitarmaking, Devon, UK

    I had no problem finding the website, no course material though. Or are you just referring to the photos of student guitars?

  12. #36
    On that website,Totnes students are interviewed, explaining what they are accomplishing (in photos with captions.) The school is presenting highlights.

    On the other hand, Ken Parker Archtoppery is my "go-to." And you don't have to watch every moment of his real-time demos. He even invites his viewers to fast forward. I must say, though, that his real-time demos give you a feel of what's taking place. You can virtually be right there building the guitar with him.
    Keep us posted

  13. #37
    Quote Originally Posted by ArchieHollow
    "An arch top moves the top differently than a flat top. A flat top bridge twists the top, an arch top bridge pushes the top up and down."
    QUESTION:
    Doesn't it make sense that a fixed bridge on a flattop acoustic would transfer the vibes in a "twist," since longtidudinal tension pulls clockwise (on a right-hand instrument) because the low E has more tension than the high E? Whereas, on an archtop with a floating bridge, longitudinal tension goes to the tailpiece attached to the tail stock; so, at the bridge there is only downward pressure, that would transfer vibes conically?
    "Most of the power that drives the top comes from the 'transverse' string force, and it's most effective when the string is moving 'vertically' with respect to the plane of the top.

    The tension of the rises and falls at twice the frequency of the fundamental of the string, and this does cause the bridge to rock forward and back. On the average, this signal is about 1/7 as powerful as the transverse signal that's trying to move the top like a loudspeaker. In addition, tops are built to resist bridge rocking, so that it takes a lot more force to rocking the bridge to get the same amount of sound that you'd get from the 'loudspeaker' motion. Finally, when the bridge is rocking, the upper and lower parts of the soundboard are out of phase with each other, and a lot of the sound that's produced simply cancels out. For all of these reasons the bridge rocking mode is not a major power producer. Altering the height of the strings off the top doesn't make a noticeable difference in the overall power output in measurements I've made. It does alter the timbre of the guitar, primarily by an increase in the second partial of the string sound, and also probably due to an added high frequency component due to a lengthwise compression wave in the string up around the 7th or 8th partial.



    Alan Carruth"
    Loudest possible sound.. - The Acoustic Guitar Forum

    Or better yet although longer.

    https://www.classicalguitardelcamp.com/viewtopic.php?t=134290

  14. #38
    Printer:
    Like you, I want a mellow sounding archtop hollow body guitar that's easy to play and easy on me. An acoustic instrument with a high quality floating pickup, so I can also play it through an amp. I'm in process of building it.
    If you think it would help, I will post pics with captions outlining the progress.

  15. #39
    Quote Originally Posted by ArchieHollow
    Printer:
    Like you, I want a mellow sounding archtop hollow body guitar that's easy to play and easy on me. An acoustic instrument with a high quality floating pickup, so I can also play it through an amp. I'm in process of building it.
    If you think it would help, I will post pics with captions outlining the progress.
    Pictures? You said pictures? We love pictures.

    Heck, if anyone wants to add to the collective knowledge here I am all for it. I am a big sharer of information, good or bad. I have posted enough of my mistakes online to show that not everything goes according to plan. My second guitar.



    Then there was a neck reset I did on a cheap Silvertone guitar.

    Marking the neck position to help in lining it up again.


    Cleaning the old glue out and making a shim for the fretboard. The execution of the dovetail joint relied on filling the joint with glue rather than having a wood on wood contact.


    The neck has a little too much relief to it.


    Have to remove the frets and level the board since the truss rod isn't adjustable.


    Removing the frets by pushing them out. No chip out of the fretboard this way. The fretboard was a bit of veneer over a plywood layer.


    Fretboard is dyed.



    Dyed the fretboard, installed frets. Added shims to the dovetail, no idea where the picture went though. Reset it and buttoned it up.


    My only previous archtop content. Mostly learning about flattops before this. And tube guitar amps, have a little of an electronic background. Just been finishing a few speaker cabinets that have been on my mind. Being of retirement age weight have been a thought and I have been going down the path of building light equipment, Not done yet, mounted the baffle today. Maybe finish it tomorrow, I need to get some screws. Two alnico Yamaha organ speaker, 29.6 lbs. I will sand it all down and make it look a little better but doubt it will leave the house all that much. Other amps for that. A few cabinets I want to finish building up beside it. So lot of projects to get done.

  16. #40
    Progress highlights
    Attached Images Attached Images Pre-build questions for a 15" acoustic bundle of joy.-img_20230313_180012914-jpg Pre-build questions for a 15" acoustic bundle of joy.-img_20230318_154822602-jpg Pre-build questions for a 15" acoustic bundle of joy.-img_20230322_164216597-jpg Pre-build questions for a 15" acoustic bundle of joy.-img_20230322_164636193-jpg 

  17. #41
    Bracing deepest at apex to support top under bridge tension
    Top plate thickness:
    0.075" @ recurve (outer)
    0.100" @ recurve (inner)
    0.125" @ waiste
    0.155" @ apex

    To be strung with:
    .009 - .042
    Attached Images Attached Images Pre-build questions for a 15" acoustic bundle of joy.-image-jpg 

  18. #42
    Cool. What size is it and what kind of wood? I am guessing Cherry but really am unsure. I guess I will have to make a mold, I have been building without the last while.

  19. #43
    Outline of Gibson Les Paul:
    16-1/2" Body length
    13-1/2" Lower Bout
    7-1/2" Waist
    9-1/2"Upper Bout
    2" Sides
    5/8" rise @ apex top and back plates
    3-1/4" overall depth @ apex
    Aromatic Red Cedar top and back plates
    Yellow Canary sides
    Attached Images Attached Images Pre-build questions for a 15" acoustic bundle of joy.-screenshot_20230324-0730402-png 

  20. #44
    Quote Originally Posted by ArchieHollow
    Outline of Gibson Les Paul:
    16-1/2" Body length
    13-1/2" Lower Bout
    7-1/2" Waist
    9-1/2"Upper Bout
    2" Sides
    5/8" rise @ apex top and back plates
    3-1/4" overall depth @ apex
    Aromatic Red Cedar top and back plates
    Yellow Canary sides
    I never thought of cedar as few people use softwood for backs (I have on some flat tops). The sides I never would have guessed. I pulled out the LP body I have to see how it feels. I forgot how heavy it is, defiantly need an arm bevel. I think I would go 2 1/2" for the depth. The arm bevel and body cut I need might throw a wrench into things, not sure how I will do that and still have the top and back do its thing. This might be harder than I thought. I could do a wedge body, which would help. I wonder if I could get away without doing the recurve somehow?
    Last edited by Printer; 03-24-2023 at 01:03 PM.

  21. #45
    The small hollow body with cedar top and back will weigh less than my '61 Gibson SG Special.

  22. #46
    Quote Originally Posted by ArchieHollow
    The small hollow body with cedar top and back will weigh less than my '61 Gibson SG Special.
    Use light tuners.

  23. #47
    A poster on another forum suggested an arm rest that stuck onto the side. I did a rough test, It might have some promiss.



    My current practice guitar behind it, I did not have any other paint around when building it.

  24. #48
    Printer:
    I really believe it’s possible to build a 2” - 2-1/2” deep archtop hollow body to include the type of bevels you’re used to on the Strat (the arm bevel on the top side of the lower bout, and the “gut” bevel at the back of the upper waist.) Lots of geometry, reinforcing and perfectly shaped joining panels. There’s likely someone doing this.

  25. #49
    Quote Originally Posted by ArchieHollow
    Printer:
    I really believe it’s possible to build a 2” - 2-1/2” deep archtop hollow body to include the type of bevels you’re used to on the Strat (the arm bevel on the top side of the lower bout, and the “gut” bevel at the back of the upper waist.) Lots of geometry, reinforcing and perfectly shaped joining panels. There’s likely someone doing this.
    One of two guitars I should be working on but the shop was full of dust so I spent some time on other messy projects before I cleaned things up.













    I bend the top to get the arm bevel. The back was a lot more difficult, a more complex curve. I used the same thickness for the back bevel as the back. The wood has been torrified so it was not all that easy to bend, the wood is Sitka from what I can tell. The panels fit was pretty good but I managed to miss-align it a little as I was gluing it in. I used CA and once I started I was pretty much committed to it. On reflection I probably would use rope and wedges and a slower glue if I ever did it again. I started a Dred for a family member also so I won't be jumping into the archtop for a little while.



    I also have a couple of tube amps I am building. A lot of different projects on the go, normal for me. I tend to get ideas and start them then jump back and forth to the project that interests me on that day. I was slogging through it with the speaker cabinets as I will have to tear my shop down as I need to have some major work on the house and probably will not have a place to work on my musical related projects for a while. Maybe why I want to get the archtop started, otherwise it might be a few years before I get back to it and I am no spring chicken. One thing I have been mulling over about the archtop is to do a carved top and a laminated back. I already have the laminations thinned down, was going to do a complete laminated guitar to see how one could be if you use good materials and build it as light as you would a solid wood guitar. I am thinking a non-carved top might give me a little more bass if I built it like a flattop. I made it through all the Archtoppery series, looks like I will need to build a few tools also. Never a dull moment.

  26. #50
    Look at you Printer--You are already doing it. Have you tried using sheet metal (aluminum, copper or steel) to make bendable templates for the cuts (gussets) that can be traced and cut with precision to be dry-fitted, and then glued in place? And, as you said, using a slower setting glue, clamping (or tying in place.)