Results 1 to 9 of 9

Thread: Harmony Batwing Truss Rod Question

  1. #1
    Registered User
    Join Date
    Sep 2013
    Location
    Los Angeles, CA
    Posts
    197

    Default Harmony Batwing Truss Rod Question

    I have an acoustic Harmony "Batwing" H8025 on the bench. Went to adjust the truss rod and found an unusual amount of threaded rod protruding from the nut. Turned the nut and the rod kept coming out through it—obviously not connected on the other end. Pulled the rod all the way out and there's no breakage or twisting on the heel end of the rod, nor even clear evidence of a broken weld where it might have been attached to an anchor bolt or second rod (I know Harmony used a two-piece compression rod on some instruments). The nut washer won't pull out easily so I can't tell if there's a second compression rod behind it. Does anyone know how these were constructed? Thanks!

    Click image for larger version. 

Name:	IMG_2482.jpg 
Views:	159 
Size:	434.2 KB 
ID:	159205
    Click image for larger version. 

Name:	IMG_2483.jpg 
Views:	174 
Size:	540.9 KB 
ID:	159204
    Click image for larger version. 

Name:	IMG_2497.jpg 
Views:	172 
Size:	670.4 KB 
ID:	159201
    Click image for larger version. 

Name:	IMG_2490.jpg 
Views:	155 
Size:	410.1 KB 
ID:	159202
    Click image for larger version. 

Name:	IMG_2495.jpg 
Views:	137 
Size:	482.0 KB 
ID:	159203

  2. #2
    Registered User Tavy's Avatar
    Join Date
    Jun 2007
    Location
    Tavistock UK
    Posts
    4,438

    Default Re: Harmony Batwing Truss Rod Question

    Well that's a puzzle for sure! Manufacturing mistake?

  3. The following members say thank you to Tavy for this post:


  4. #3
    Registered User
    Join Date
    Sep 2013
    Location
    Los Angeles, CA
    Posts
    197

    Default Re: Harmony Batwing Truss Rod Question

    Judging from Frank Ford's site (http://www.frets.com/FretsPages/Luth...armonyrod.html) and this Harmony site (http://harmony.demont.net/kamikazie.php?page=005) I suspect this is the compression rod system. Likely there was an insubstantial weld at the heel end that snapped when the nut was turned. Ford was able to free up that washer/collar and remove it with an Exacto knife. I reckon I'll try the same thing, hoping I'll find the second rod in there and can reattach it. Anything not to have to remove the fretboard. Still, if anyone knows more than I it would be great to hear about it. Thanks.

  5. #4
    Registered User Timbofood's Avatar
    Join Date
    Mar 2007
    Location
    Kalamazoo, MI.
    Posts
    7,487

    Default Re: Harmony Batwing Truss Rod Question

    One of these days I will find one for a reasonable price at a yard sale and grab it until I find it for the right price, I'm not worrying. But I'm,ready to dive into the Yank Rachell pool for a swim with one of these!
    Timothy F. Lewis
    "If brains was lard, that boy couldn't grease a very big skillet" J.D. Clampett

  6. #5
    Registered User
    Join Date
    Sep 2013
    Location
    Los Angeles, CA
    Posts
    197

    Default Re: Harmony Batwing Truss Rod Question

    Harmony Batwing mando truss rod question answered.

    In addition to the other sites linked above, this one also encouraged me to guess I was dealing with a double truss rod: http://www.moonlightluthiers.com/har...nhancement.htm

    The washer/collar under the nut looked right, so I figured a second rod was hiding behind it. Removing the nut and cleaning the slot out a little allowed me to grab the collar and pull it out, revealing the other rod. Getting that out was considerably trickier, but managed to do it with some probing, prodding, and pulling. Now I just need to take it over to a pal's studio and re-weld the rods at the heel end.

    Click image for larger version. 

Name:	IMG_2519.jpg 
Views:	149 
Size:	643.0 KB 
ID:	159312

  7. The following members say thank you to Doug Freeman for this post:


  8. #6
    Registered User Tavy's Avatar
    Join Date
    Jun 2007
    Location
    Tavistock UK
    Posts
    4,438

    Default Re: Harmony Batwing Truss Rod Question

    Wow, well done getting both of those out!

  9. #7

    Default Re: Harmony Batwing Truss Rod Question

    Quote Originally Posted by Doug Freeman View Post
    Now I just need to take it over to a pal's studio and re-weld the rods at the heel end.

    Click image for larger version. 

Name:	IMG_2519.jpg 
Views:	149 
Size:	643.0 KB 
ID:	159312
    Once it is re-welded, how are you going to get it back in place without removing the fingerboard? Doesn't appear to be room from the peghead opening....

  10. #8
    Registered User
    Join Date
    Sep 2013
    Location
    Los Angeles, CA
    Posts
    197

    Default Re: Harmony Batwing Truss Rod Question

    Quote Originally Posted by Jeff Mando View Post
    Once it is re-welded, how are you going to get it back in place without removing the fingerboard? Doesn't appear to be room from the peghead opening....
    I didn't get a picture of it, but the truss rod slot behind the collar/washer is tall (i.e., deep) enough for both rods, one on top of the other, to slide right in. The threaded portion of the lower rod protrudes through the collar, while the upper one snugs up against the back of the collar. Turning the nut forces the collar backward, causing the upper rod to arch upward and apply back pressure against the top of the neck. Attaching a couple pics of the rods welded together and assembled with the collar/washer and nut affixed. The nut was tightened a bit at this point to test the weld before putting it all back together. Which it now is, and is working great.

    Click image for larger version. 

Name:	IMG_2566.jpg 
Views:	150 
Size:	673.4 KB 
ID:	159693 Click image for larger version. 

Name:	IMG_2563.jpg 
Views:	121 
Size:	716.5 KB 
ID:	159692

  11. The Following 3 Users Say Thank You to Doug Freeman For This Useful Post:


  12. #9
    Registered User Tavy's Avatar
    Join Date
    Jun 2007
    Location
    Tavistock UK
    Posts
    4,438

    Default Re: Harmony Batwing Truss Rod Question

    Great stuff!

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •