Hey everyone,
This is somewhat of a continuation of my last post but taking a new direction. I scored a cheap banjo in an estate sale and will be rebuilding the rim as I discovered that the tone ring was poorly fit and the rim is damaged and undersized to be able to properly fit the tone ring.
see more here:
banjohangout.org/topic/410326/#5157530
I have decided I will try to make one if I can. I am a bit new to Mastertone geometry as this is my first banjo in this configuration, but my first step was to decide whether I want to recreate banjo geometry to the best of my ability to measure the existing rim or if I can use standard Mastertone geometry.
I have my current parts drawn. see attached pictures. that is the drawing to the best of my ability measured with a set of calipers. Sorry that I my drawings are in inches on the rim and mm on the tone ring... (it upsets me too)
The ID and OD are not pictured but I measured them for the...
Rim:
ID = 9.515"
OD= (9.515 + (0.75*2)) = 11.015"
Tone Ring:
ID = 9.413"
OD = 11.17"
I have some plans that have a drawing for two piece flange (which my banjo has) but it has an arch top instead of a flathead tone ring.
My questions would be:
1. Do I want to...
a. just recreate my banjo rim from the drawing that I came up with from my own measurements to the best of my ability. where I fix the height above the bead to the inner tone ring bearing will seat properly and add a square shelf for the OD tone ring bearing to seat
or
b. Use standard mastertone geometry from a set of plans that I have. <-- confused on how to profile the bead geometry but the dimensions look similar enough to my rim that they would likely work. If i am correct the only dimensions I need to change from the set of plans I have would be the everything above the bead where the tone ring seats to switch from arch top to flathead
A big thing I would need to confirm would be hole spacing and bead location to ensure the neck will fit.
An I idea I had was to 3D print a 30 degree section of my different options to see about fitment.
At some point tomorrow I will try to get a CAD drawing made based on my set of blueprints.
Edited by - JDE4570 on 09/20/2026 20:05:16
Here Is a drawing based on a set of plans I have.
I modified the area above the bead to to fit the dimensions of my flathead tone ring instead of the listed dimensions of an archtop
quote:
Originally posted by JDE4570Here Is a drawing based on a set of plans I have.
I modified the area above the bead to to fit the dimensions of my flathead tone ring instead of the listed dimensions of an archtop
If you turn the rim to those specs, you should be fine. Just remember to turn it so the tone ring slips on and off easily. Too tight and it will choke the sound.
As Culloden mentioned, the misaligned hole at upper isn’t uncommon, and I wouldn’t worry about it. If it bothers you doweling, trimming the dowel and redrilling is very easy quick free work.
As for the inner lip of flat head tone ring suspended mid-air, it also can be fixed free in couple of ways. You can trim off some wood on exterior wood lip, to allow exterior or outer tone ring skirt to sit lower, therefore bringing inner lip to bear on rim.
Or, you can glue 36 grit sandpaper on sheet of plywood and sand the exterior skirt of your tone ring down until inner skirt bears on rim. Or, you can have tiny amount lathed off exterior skirt until inner skirt bears on rim. Any of those options will work fine, with most dangerous being to remove tiny portion of rim upper wooden bead. But, I don’t think it’d really be an issue. A little stain and good to go.
I had a tone ring that wouldn’t fully seat on inner skirt to upper inside rim edge, and I sanded a flathead down on outer lower skirt with sanding blocks and rough grit.
Again, the outer skirt of tone ring need NOT be flush to wooden bead, the outer skirt is a location device basically. The inner skirt needs to bear on top inner rim fitted well enough you can hold rim/ring assembly in one hand and NOT be able to pull a dollar bill out. And you need to do this all around. And yes, the ring needs to be removable from the rim without too much effort but not tons of slop. If there’s tons of slop, side to side, you can use thin sandpaper or wood veneer to build rim up.
JDE4370. Do you know size feet wire to use in Morgan Monroe m n b 2 I need replacing some frets in my
quote:
Originally posted by kyslimJDE4370. Do you know size feet wire to use in Morgan Monroe m n b 2 I need replacing some frets in my
I do not unfortunately. I am new to this banjo as of a few days ago.
I spoke to Eric Sullivan today. I think I am going to go with a Sullivan rim and tone ring and modify my neck to fit standard geometry. (if it doesnt fit) He sounds like he will take good care to fit things together.
My Logic behind that is to be able to reuse the rim if I later want to buy a neck and start building something high end. that will also require me to swap coordinator rods and neck studs now too, but will be worth it to have a reusable pot assembly for a future build if I upgrade to a high end neck and/or swap other hardware later.
he was also willing to turn it to my original tone ring if needed but my thoughts are also that if i have such a nice rim I may as well make sure I have a nice tone ring to match.
JDE4370. I have Morgan Monroe MNB2 banjo as my primary banjo. My banjo was made on 9-11-2003. The original owner had a luthier take out the original tone ring. He replaced it with a Tennessee 20 tone ring. To get the tone ring to fit right, he made a shim so the Tennessee 20 ring would fit. He had clear First Quality head installed to show off the tone ring.
This banjo has a great sound and can be loud. It also has a Kateyz bridge installed.
I've had a Deering owner recently play my banjo. He wanted all the info on the Tennessee 20 tone ring. He wants to but one in his Deering.
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