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Old 10-24-2021, 12:12 PM
John Eldredge John Eldredge is offline
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Default Stelling Staghorn Facelift

Hello all. The Stelling Staghorn is back in the shop. She was setup and tuned up for a festival/competition in Branson, MO, where she was a big hit. The customer was very pleased with how well she played and sounded, as were the other competitors who played her. However, during the tune up, a few issues were found that needed to be addressed, so she’s back for a facelift.
Pic 1 is the Staghorn on the eval bench in my backroom shop; it’s quite convenient for quick things, like this. Resonator is off, so all the adjustment fiddly-bits are accessable. Everything was checked for smooth operation.
Pic 2 identifies the main issue; nice scallop on the bridge, no? The scallop at the saddle is replicated at the bridge feet, not good. As well, string tension over time has rocked the bridge slightly forward, creating a hard bearing edge at the front face. This has caused a hard crease in the head material which would complicate a simple bridge replacement. A second, minor, issue is that the truss rod feels like it’s at the end of its adjustment range. Neck set, relief, and all that are fine just now, but I would prefer to have an extra quarter turn in reserve, as it were.
So: Replace the head and bridge. De-burr, clean and lube truss rod, and nut, threads. Tune her up to pitch and evaluate the setup. Adjust coordinator rods, as necessary. While she’s apart, I’ll flitz the metal parts, so she’ll look like new, when finished.
When working on expensive instruments, like this one, I document the job with notes and pictures, for my files and for the customer. I’ll put some of those up.
John
Attached Images
File Type: jpg Stelling Staghorn.jpg (36.1 KB, 77 views)
File Type: jpg Staghorn Bridge.jpg (19.5 KB, 76 views)
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Old 10-28-2021, 03:03 PM
John Eldredge John Eldredge is offline
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First thing is to take off the strings, arm rest, tailpiece, and head assembly; so pic 1 is all the parts laid out. It's a good idea to have a small box to put all the screws, plates, and pieces of parts into. I'll reassemble the arm rest and retainer plate and use some tape, just to make sure parts don't get confused.
Next I put the coordinator rods in neutral position, letting the rim get as much into round as it wishes. Right about now is a good time to make sure the head retaining ring is flat. If it isn't, flatten it (on the edge that engages the rim). A piece of glass works great; I use the machined table for our oscillating spindle sander, but any really flat surface is fine.
Clean everything you can and then put on the new head, cover with the retaining ring, and engage all 24 lugs. I make them finger tight using the typical octagonal star pattern, doing it twice around. Then, I like to flip her over onto the top of the retaining ring, keeping the ring top flat on the table. The neck is angled, so a sliding spacer block under the fretboard is all that's needed. I let her rest, like this, overnight. I think the weight of the pot on the head/ring interface helps things "settle" into place, and get things a bit more "nominal", before tensioning time. That's pic 2; everything relaxed, deep breath, Hatha Shavasana. Leaving the sleeping beauty to her meditations, and to avoid disturbing her Wa at this juncture, I'll take up the final steps in the next post.
Attached Images
File Type: jpg DSC_0001.JPG (130.6 KB, 67 views)
File Type: jpg DSC_0002.JPG (155.1 KB, 67 views)
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Old 10-28-2021, 03:23 PM
SpruceTop SpruceTop is offline
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Thanks, John, for this very informative thread, and I'll be watching!

Current Banjos:
Vega No. 2 Tubaphone
OME North Star Walnut
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On Order:
Ozark Custom 12-inch Figured Cherry
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Old 10-29-2021, 06:34 AM
John Eldredge John Eldredge is offline
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Next morning is time to tension the head. After relaxation, all the lugs needed a full 1/2 to 3/4 turn to get back to finger snug. Starting from there, I tighten, in the paired, octagonal, star pattern, until I feel a solid uniformity. At this point, I will flip her over and do a tension check, with the drum-dial, at every lug location, looking for around 88. For the Stelling, since rumor has it they are "different", I tap tuned the head to get a drum-dial tension/frequency check point.
Pic 1, a mike sits over the head and feeds into a spectrum analysis program. Tap the head with a golf ball core on a bamboo skewer in front of each of the 24 lugs. The screen shows the frequency response from 10 to 1500 Hz. Zoom in to the range of interest and read the freq peak. Ya'll might be able to see the tall peak in the select window in the picture. (My system is set up for an average of 10 taps per buffer fill. I use this for other measurements that need the accuracy and I'm too lazy to adjust the settings. 2 or 3 per buffer fill is fine.)
Pic. 2. Then the tailpiece and strings go on and the new bridge is installed. Tune to pitch and adjust the bridge position to for proper intonation on the 1st and 4th strings. I played her a bit to let her get used to the new parts and let all the pieces settle down. I tensioned the head to a drum-dial reading of 91 at each of the lugs. Tap tuning put the head frequency right smack between G# and A. I don’t like to put the main response node at a note frequency. The interaction causes interference between the note and head resonance, and can cause the note to sound “clangy” or “dead”, depending on phase. A quarter tone above G#, or about 427 Hz, is a good target. Turns out that 427 Hz reads 90.9 on my drum-dial, so I have a calibration point for a Stelling head on a Stelling banjo.
The final steps were straight-forward; The coordinator rods were neutral so there was lots of room to move. Only a very minor tweak was needed to get the action right at the 12th and 22nd frets. The truss rod was fine (already adjusted a couple weeks ago) and the frets had been dressed and crowned. I adjusted the neck to a string height just a skoosh lower than nominal spec because the customer competes in a lot of banjo competitions and playability is a necessity.
Cleaned her up, flitzed the metal, fixed a piece of the case lining that was coming loose, and brought her back to her mother. Had a nice impromptu jam session; banjo, two guitars, and a piano.
Attached Images
File Type: jpg DSC_0004.JPG (139.0 KB, 56 views)
File Type: jpg DSC_0006.JPG (116.6 KB, 57 views)
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  #5  
Old 10-29-2021, 06:36 AM
John Eldredge John Eldredge is offline
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Quote:
Originally Posted by SpruceTop View Post
Thanks, John, for this very informative thread, and I'll be watching!
You are very welcome Sprucetop. Glad you found it interesting.
John
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Old 12-12-2021, 01:21 AM
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Zissou Intern Zissou Intern is offline
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This was an informative and enjoyable read. Thanks.
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